Patent Application
20240018838
Embodiments of the present invention relate, generally, to explosive downhole tools having improved wellbore conveyance properties. In particular, the explosive downhole tools have a configuration that allows the tools to be more easily run in and out of a wellbore. The configuration may be useful when the wellbore geometry includes restrictions from, e.g., seats, tool joints, and other inner diameter restrictions, which form ledges on which sharp corners of the tool profile would otherwise catch or get stuck. Embodiments of the present invention also relate, generally, to explosive downhole tools having improved debris reducing properties. In particular, the explosive downhole tools may have a configuration and/or be formed of a material that minimizes or eliminates debris from the tool in the wellbore after the explosive downhole tool is actuated. The explosive downhole tools may be cutting tools for cutting or severing a tubular, or may be expansion tools for selectively expanding a wall of a tubular. Expansion tools, such as shaped charge tools, may be used for selectively expanding a wall of a tubular to compress micro annulus pores and reduce micro annulus leaks, collapse open channels in a cemented annulus adjacent the tubular, minimize other inconstancies or defects in the cemented annulus, and to form a restriction. The tubular may include, but is not limited to, pipe, tube, casing and/or casing liner. Embodiments of the present invention further relate, generally, to explosive units for explosive column downhole tools. The explosive units may be divided into sections having a predetermined mass that makes the sections safer to handle and comply with government transportation safety regulations.
It can be important in the oilfield industry for wellbore tools, such as explosive cutters and explosive expansion tools, to be easily run in and sometimes out of a well, as doing so can save time and money during wellbore operations. Wellbores may have an inner geometry that includes restrictions from such elements as seats, tool joints, and/or other inner diameter restrictions. The restrictions may form ledges or internal diameters in the wellbore on which sharp corners of a conventional explosive downhole tool may catch or get stuck. Once stuck, attempts to free or retrieve the explosive downhole tool may damage the tool and render it inoperable. In addition, attempts to free or retrieve the explosive downhole tool may cause the tool to be separated from the conveyance device, (such as a wireline, coiled tubing, etc.), which then creates a large debris issue or unspent explosives in the wellbore and expensive fishing operations which may not always be successful. A need thus exists for an explosive downhole tool having a configuration that allows the tool to be more easily conveyed into and out of a wellbore.
It can be desirable in the oilfield industry to minimize the amount of debris, such as pieces of an actuated explosive device or downhole tool, left in a well. This is because the debris can not only restrict other tools from being subsequently run in the wellbore, but also flow and the circulation of fluids in the wellbore during the production of oil and gas. Debris can be a problem even when the well is to be plugged and abandoned, as it can be necessary to run another tool into the wellbore after the plug and abandonment and the debris could block or otherwise restrict the next tool from being run. The importance of reducing or even eliminating debris is amplified in producing wells where debris could not only restrict other tools being run but can also cause the production of oil and gas to be delayed or stopped. Therefore, a need exists for an explosive downhole tool having a configuration and/or being formed of a material that minimizes or eliminates debris from the tool in the wellbore after the explosive downhole tool is actuated.
Explosive column downhole tools can include a series of explosive units as the explosive material for cutting, severing or selectively expanding a wall of a tubular in a wellbore. A predetermined number of explosive units may be loaded onto explosive column downhole tools. The number, size and/or explosive volume (weight) of explosive units required to perform the cutting or expansion operation may depend on the physical properties of the tubular and the downhole conditions in the wellbore. The units may thus be transported separately from the assembled explosive column downhole tool and loaded onto the explosive column downhole tool at the wellsite. Government regulations may limit the size of explosive units that can be transported in a vehicle or stored. Accordingly, a need exists for providing relatively larger explosive units that can be transported in compliance with government regulations.
The embodiments of the present invention meet the above needs.
An object of the present disclosure is to provide an explosive downhole tool having a configuration that allows the explosive downhole tool to be more easily conveyed into and out of a wellbore. The configuration helps the explosive downhole tool avoid catching or getting stuck on restrictions in a wellbore in form of ledges protruding from, e.g., seats, tool joints, and other inner diameter restrictions. Another object of the present disclosure is to provide explosive downhole tools, such as cutting tools for cutting or severing a tubular, or expansion tools for selectively expanding a wall of a tubular, having a configuration and/or being formed of a material that minimizes or eliminates debris from the tool in the wellbore after the explosive downhole tool is actuated. A further object of the present disclosure is provided explosive units, for an explosive column downhole tool, that may be divided into sections having a predetermined mass that makes the sections safer to handle and comply with government transportation safety regulations.
According to one embodiment, an explosive downhole tool for at least one of cutting and selectively expanding a wall of a tubular comprises a housing comprising a window section, an upper housing part on one side of the window section, and a lower housing part on an opposite side of the window section; an explosive charge within the housing and comprising a predetermined amount of explosive for at least one of: (i) cutting the wall of the tubular; and (ii) expanding, without puncturing, the wall of the tubular into a protrusion extending outward into an annulus adjacent the wall of the tubular, wherein each of the upper housing part 821 and the lower housing part 822 comprises an outer surface that faces away from the housing 820, and the outer surface of at least one of the upper housing part 821 and the lower housing part 822 is rounded so as to be devoid of corners.
In an embodiment, the explosive charge is a shaped charge.
In an embodiment, the explosive downhole tool further comprises an intermediate connector attached to one of the upper housing part and the lower housing part.
In an embodiment, the housing is formed of a dissolvable material.
In an embodiment, the dissolvable material comprises a magnesium alloy.
In an embodiment, the intermediate connector is formed of a dissolvable material.
According to another embodiment, an explosive downhole tool for at least one of cutting and selectively expanding a wall of a tubular comprises a first housing; at least a second housing spaced axially from the first housing along a length of the explosive downhole tool; and an intermediate connector connecting the first housing to the second housing, wherein each of the first housing and the second housing comprises: an explosive charge comprising a predetermined amount of explosive for at least one of: (i) cutting the wall of the tubular; and (ii) expanding, without puncturing, the wall of the tubular into a protrusion extending outward into an annulus adjacent the wall of the tubular; and a window section, an upper housing part on one side of the window section, and a lower housing part on an opposite side of the window section, wherein each of the upper housing part and the lower housing part comprises an outer surface that faces away from the housing, and the outer surface of at least one of the upper housing part and the lower housing part is rounded so as to be devoid of corners.
In an embodiment, the explosive charge is a shaped charge.
In an embodiment, at least one of the first housing and the second housing is formed of a dissolvable material.
In an embodiment, the intermediate connector 814 is formed of a dissolvable material.
According to a further embodiment, an explosive downhole tool for at least one of cutting and selectively expanding a wall of a tubular comprises a first housing; at least a second housing spaced axially from the first housing along a length of the explosive downhole tool; an explosive charge comprising a predetermined amount of explosive for at least one of: (i) cutting the wall of the tubular; and (ii) expanding, without puncturing, the wall of the tubular into a protrusion extending outward into an annulus adjacent the wall of the tubular; and an intermediate guide between the first housing and the second housing, wherein the intermediate guide comprises a plurality of fins spaced radially from each other around an axis of the explosive downhole tool, each of the plurality of fins extending from one of the first housing and the second housing, and comprising a height relative to the axis that decreases in a direction away from the one of the first housing and the second housing.
In an embodiment, the intermediate guide comprises a first intermediate guide portion extending from the first housing and a second intermediate guide portion extending from the second housing toward the first intermediate guide portion.
In an embodiment, the intermediate guide is formed of sand casted metal.
In an embodiment, the intermediate guide is formed of porous material.
In an embodiment, each of the plurality of fins is triangular shaped.
In an embodiment, the first intermediate guide portion comprises a first connector that connects with a second connector of the second intermediate guide portion.
In an embodiment, a method of at least one of cutting and selectively expanding a wall of a tubular via the explosive downhole tool comprises positioning the explosive downhole tool within the tubular; and actuating the explosive downhole tool to ignite the explosive charge causing a shock wave that travels radially outward to impact the tubular.
In another embodiment, an explosive unit for an explosive column tool comprises explosive material, wherein the explosive unit is divided into two or more sections that are attachable to each other, and each of the two or more sections has a Division 1.4 designation that is based on Series 6 Tests of the United Nations Recommendations on the Transport of Dangerous Goods.
In an embodiment, the two or more sections are equal to each other in size and shape.
In an embodiment, thee explosive unit further comprises a central aperture through which a loading rod of the explosive column tool passes for loading the explosive unit onto the explosive column tool.
In an embodiment, the two or more sections comprise a first central section and a second outer section that surrounds a circumference of the first central section.
In an embodiment, the explosive unit has a circular shape.
In an embodiment, a method of assembling an explosive column tool comprises receiving the explosive that is divided into the two or more sections; attaching the two or more sections to each other; and loading the explosive unit onto the explosive column tool.
In an embodiment, a method of actuating an explosive column tool in a wellbore comprises positioning the explosive column tool comprising the explosive unit within the wellbore; and actuating the explosive column tool to ignite the explosive unit.
According to another embodiment, a method of selectively expanding a wall of a tubular via an expansion tool comprising at least three explosive units spaced axially along a length of the expansion tool comprises: positioning the expansion tool within the tubular; and simultaneously actuating the at least three explosive units to cause a shock wave from each of the at least three or more explosives to travel radially outward to impact the tubular at a first location, a second location, and a third location, respectively, wherein each impact expands at least a portion of the wall of the tubular radially outward without perforating or cutting through said at least a portion of the wall, to form a protrusion of the tubular, wherein each protrusion extends into an annulus adjacent an outer surface of the wall of the tubular.
According to further embodiment, a method of selectively expanding a wall of a tubular via an expansion tool comprising at least three explosive units spaced axially along a length of the expansion tool comprises: positioning the expansion tool within the tubular; and selectively actuating one or more of the at least three explosive units, wherein each actuation causes a shock wave from a respective one of the at least three explosives to travel radially outward to impact the tubular at a location thereof, wherein the impact expands at least a portion of the wall of the tubular radially outward without perforating or cutting through said at least a portion of the wall, to form a protrusion of the tubular, wherein the protrusion extends into an annulus adjacent an outer surface of the wall of the tubular.
Various embodiments are hereafter described in detail and with reference to the drawings wherein like reference characters designate like or similar elements throughout the several figures and views that collectively comprise the drawings.
Before explaining the disclosed embodiments in detail, it is to be understood that the present disclosure is not limited to the particular embodiments depicted or described, and that the invention can be practiced or carried out in various ways. The disclosure and description hemin are illustrative and explanatory of one or more presently preferred embodiments and variations thereof, and it will be appreciated by those skilled in the art that various changes in the design, organization, means of operation, structures and location, methodology, and use of mechanical equivalents may be made without departing from the spirit of the invention.
As well, it should be understood that the drawings are intended to illustrate and plainly disclose presently preferred embodiments to one of skill in the art, but are not intended to be manufacturing level drawings or renditions of final products and may include simplified conceptual views to facilitate understanding or explanation. Further, the relative size and arrangement of the components may differ from that shown and still operate within the spirit of the invention.
Moreover, as used herein, the terms “up” and “down”, “upper” and “lower”, “upwardly” and downwardly”, “upstream” and “downstream”; “above” and “below”; and other like terms indicating relative positions above or below a given point or element are used in this description to more clearly describe some embodiments discussed herein. However, when applied to equipment and methods for use in wells that are deviated or horizontal, such terms may refer to a left to right, right to left, or other relationship as appropriate. In the specification and appended claims, the terms “pipe”, “tube”, “tubular”, “casing” and/or “other tubular goods” are to be interpreted and defined generically to mean any and all of such elements without limitation of industry usage. Because many varying and different embodiments may be made within the scope of the concept(s) herein taught, and because many modifications may be made in the embodiments described herein, it is to be understood that the details herein are to be interpreted as illustrative and non-limiting.
A housing 20 can be secured to the top sub 12 by, for example, an internally threaded housing sleeve 22. The O-ring 18 can seal the interface from fluid invasion of the interior housing volume. A window section 24 of the housing interior is an inside wall portion of the housing 20 that bounds a cavity 25 around the shaped charge between the outer or base perimeters 52 and 54. In an embodiment, the upper and lower limits of the window 24 are coordinated with the shaped charge dimensions to place the window “sills” at the approximate mid-line between the inner and outer surfaces of the explosive material 60. The housing 20 may be a frangible steel material of approximately 55-60 Rockwell “C” hardness.
As shown, below the window 24, the housing 20 can be internally terminated by an integral end wall 32 having a substantially flat internal end-face 33. The external end-face 34 of the end wall may be frusto-conical about a central end boss 36. A hardened steel centralizer assembly 38 can be secured to the end boss by assembly bolts 39a, 39b, wherein each blade of the centralizer assembly 38 is secured with a respective one of the assembly bolts 39a, 39b (i.e., each blade has its own assembly bolt).
A shaped charge assembly 40 can be spaced between the top sub end face 15 and the internal end-face 33 of the housing 20 by a pair of resilient, electrically non-conductive, ring spacers 56 and 58. In some embodiments, the ring spacers may comprise silicone sponge washers. An air space of at least 0.25 centimeters (0.1 inches) is preferred between the top sub end face 15 and the adjacent face of a thrust disc 46. Similarly, a resilient, non-conductive lower ring spacer 58 (or silicone sponge washer) provides an air space that can be at least 0.25 centimeters (0.1 inches) between the internal end-face 33 and an adjacent assembly lower end plate 48.
Loose explosive particles can be ignited by impact or friction in handling, bumping or dropping the assembly. Ignition that is capable of propagating a premature explosion may occur at contact points between a steel, shaped charge thrust disc 46 or end plate 48 and a steel housing 20. To minimize such ignition opportunities, the thrust disc 46 and lower end plate 48 can be fabricated of non-sparking brass. In an embodiment, the thrust disc 46 and lower end plate 48 may be formed of zinc, or a zinc alloy material. For instance, the thrust disc 46 and lower end plate 48 may be formed of zinc powder or powder including zinc. Upon detonation of the explosive material 60, the zinc is consumed by the resulting explosion such that there is very little, if any, debris left over from the thrust disc 46 and lower end plate 48. As a result, there may be less debris in the well that could later obstruct the running of other tools in the well. For the same reasons, i.e., to minimize the amount of debris after detonation of the explosive material 60, the housing 20 may also be formed of zinc, or a zinc alloy material.
The outer faces 91 and 93 of the end plates 46 (upper thrust disc or back up plates) and 48, as respectively shown by
The explosive material 60 may be formed into explosive units 60. The explosive units 60 traditionally used in the composition of shaped charge tools comprises a precisely measured quantity of powdered, high explosive material, such as RDX, HNS or HMX. The explosive material 60 may be formed into units 60 shaped as a truncated cone by placing the explosive material in a press mold fixture. A precisely measured quantity of powdered explosive material, such as RDX, HNS or HMX, is distributed within the internal cavity of the mold. Using a central core post as a guide mandrel through an axial aperture 47 in the upper thrust disc 46, the thrust disc is placed over the explosive powder and the assembly subjected to a specified compression pressure. This pressed lamination comprises a half section of the shaped charge assembly 40. The explosive units 60 may be symmetric about a longitudinal axis 13 extending through the units 60.
The lower half section of the shaped charge assembly 40 can be formed in the same manner as described above, having a central aperture 62 of about 0.3 centimeters (0.13 inches) diameter in axial alignment with thrust disc aperture 47 and the end plate aperture 49. A complete assembly comprises the contiguous union of the lower and upper half sections along the juncture plane 64. Notably, the thrust disc 46 and end plate 48 are each fabricated around respective annular boss sections 70 and 72 that provide a protective material mass between the respective apertures 47 and 49 and the explosive material 60. These bosses are terminated by distal end faces 71 and 73 within a critical initiation distance of about 0.13 centimeters (0.05 inches) to about 0.25 centimeters (0.1 inches) from the assembly juncture plane 64. The critical initiation distance may be increased or decreased proportionally for other sizes. Hence, the explosive material 60 is insulated from an ignition wave issued by the detonator 31 until the wave arrives in the proximity of the juncture plane 64.
The apertures 47, 49 and 62 for the
The
In this embodiment, absent from the explosive material units 60 is a liner that is conventionally provided on the exterior surface of the explosive material and used to cut through the wall of a tubular. Instead, the exterior surface of the explosive material is exposed to the inner surface of the housing 20. Specifically, the housing 20 comprises an outer surface 53 facing away from the housing 20, and an opposing inner surface 51 facing an interior of the housing 20. The explosive units 60 each comprise an exterior surface 50 that faces and is exposed to the inner surface 51 of the housing 20. Describing that the exterior surface 50 of the explosive units 60 is exposed to the inner surface 51 of the housing 20 is meant to indicate that the exterior surface 50 of the explosive units 60 is not provided with a liner, as is the case in conventional cutting devices. The explosive units 60 can comprise a predetermined amount of explosive material sufficient to expand at least a portion of the wall of the tubular into a protrusion extending outward into an annulus adjacent the wall of the tubular. For instance, testing conducted with a 72 grams (2.54 ounces) HMX, 6.8 centimeter (2.7 inches) outer diameter expansion charge on a tubular having a 11.4 centimeter (4.5 inch) outer diameter and a 10.1 centimeter (3.98 inch) inner diameter resulted in expanding the outer diameter of the tubular to 13.5 centimeters (5.32 inches). The expansion was limited to a 10.2 centimeter (4 inch) length along the outer diameter of the tubular. It is important to note that the expansion is a controlled outward expansion of the wall of the tubular, and does not cause puncturing, breaching, penetrating or severing of the wall of the tubular. The annulus may be formed between an outer surface of the wall of the tubular being expanded and an inner wall of an adjacent tubular or a formation. Cement located in the annulus is compressed by the protrusion, reducing the porosity of the cement by reducing the number of micro annulus pores in the cement or other sealing agents. The reduced-porosity cement provides a seal against moisture seepage that would otherwise lead to cracks, decay and/or contamination of the cement, casing and wellbore. The compressed cement may also collapse and/or compress open channels in a cemented annulus, and/or may compress the cemented annulus to cure other defects or inconsistencies in the cement (such as due to inconsistent viscosity of the cement, and/or a pressure differential in the formation).
A method of selectively expanding at least a portion of the wall of a tubular using the tool 10 described herein may be as follows. The tool 10 is assembled including the housing 20 containing explosive material 60 adjacent two end plates 46, 48 on opposite sides of the explosive material 60. As discussed in the embodiment above, the housing 20 comprises an inner surface 51 facing an interior of the housing 20, and the explosive material 60 comprises an exterior surface 50 that faces the inner surface 51 of the housing 20 and is exposed to the inner surface 51 of the housing 20 (i.e., there is no liner on the exterior surface 50 of the explosive material 60).
A detonator 31 (see
The protrusion “P” may impact the inner wall of the outer tubular T2 after detonation of the explosive material 60. In some embodiments, the protrusion “P” may maintain contact with the inner wall of the outer tubular T2 after expansion is complete. In other embodiments, there may be a small space between the protrusion “P” and the inner wall of the outer tubular T2. For instance, the embodiment of
Expansion of the inner tubular T1 at the protrusion “P” causes that portion of the wall of the inner tubular T1 to be work-hardened, resulting in greater yield strength of the wall at the protrusion “P”. The portion of the wall having the protrusion “P” is not weakened. In particular, the yield strength of the inner tubular T1 increases at the protrusion “P”, while the tensile strength of the inner tubular T1 at the protrusion “P” decreases only nominally. Expansion of the inner tubular T1 at the protrusion “P” thus strengthens the tubular without breaching the inner tubular T1.
The magnitude of the protrusion in the embodiment discussed above depends on several factors, including the amount of explosive material in the explosive units 60, the type of explosive material, the physical profile of the exterior surface 50 of the explosive units 60, the strength of the inner tubular T1, the thickness of the tubular wall, the hydrostatic pressure bearing on the inner tubular T1, and the clearance adjacent the tubular being expanded, i.e., the width of the annulus “A” adjacent the tubular that is to be expanded. In the embodiment if
The method of selectively expanding at least a portion of the wall of a tubular T1 using the shaped charge tool 10 described herein may be modified to include determining the following characteristics of the tubular T1: a material of the tubular T1, a thickness of a wall of the tubular T1; an inner diameter of the tubular T1, an outer diameter of the tubular T1, a hydrostatic pressure bearing on the tubular T1, and a size of a protrusion “P” to be formed in the wall of the tubular T1. Next, the explosive force necessary to expand, without puncturing, the wall of the tubular T1 to form the protrusion “P”, is calculated, or determined via testing, based on the above determined material characteristics. As discussed above, the determinations and calculation of the explosive force can be performed via a software program executed on a computer. Physical hydrostatic testing of the explosive expansion charges yields data which may be input to develop computer models. The computer implements a central processing unit (CPU) to execute steps of the program. The program may be recorded on a computer-readable recording medium, such as a CD-ROM, or temporary storage device that is removably attached to the computer. Alternatively, the software program may be downloaded from a remote server and stored internally on a memory device inside the computer. Based on the necessary force, a requisite amount of explosive material for the one or more explosive material units 60 to be added to the shaped charge tool 10 is determined. The requisite amount of explosive material can be determined via the software program discussed above.
The one or more explosive material units 60, having the requisite amount of explosive material, is then added to the shaped charge tool 10. The loaded shaped charge tool 10 is then positioned within the tubular T1 at a desired location. Next, the shaped charge tool 10 is actuated to detonate the one or more explosive material units 60, resulting in a shock wave, as discussed above, that expands the wall of the tubular T1 radially outward, without perforating or cutting through the wall, to form the protrusion “P” The protrusion “P” extends into the annulus “A” adjacent an outer surface of the wall of the tubular T1.
A first series of tests was conducted to compare the effects of sample explosive units 60, which did not have a liner, with a comparative explosive unit that included a conventional liner on the exterior surface thereof. The explosive units in the first series had 15.88 centimeter (6.25 inch) outer housing diameter, and were each tested separately in a respective 17.8 centimeter (7 inch) outer diameter test pipe. The test pipe had a 16 centimeter (6.3 inch) inner diameter, and a 0.89 centimeter (0.35 inch) Wall Thickness, L-80.
The comparative sample explosive unit had a 15.88 centimeter (6.25 inch) outside housing diameter and included liners. Silicone caulk was added to foul the liners, leaving only the outer 0.76 centimeters (0.3 inches) of the liners exposed for potential jetting. 77.6 grams (2.7 ounces) of IMX main explosive was used as the explosive material. The sample “A” explosive unit had a 15.88 centimeter (6.25 inch) outside housing diameter and was free of any liners. 155.6 grams (5.5 ounces) of HMX main explosive was used as the explosive material. The sample “B” explosive unit had a 15.88 centimeter (6.25 inch) outside housing diameter and was free of any liners. 122.0 grams (4.3 ounces) of HMX main explosive was used as the explosive material.
The test was conducted at ambient temperature with the following conditions. Pressure: 20.7 Mpa (3,000 psi). Fluid: water. Centralized Shooting Clearance: 0.06 centimeters (0.03 inches). The Results are provided below in Table 1.
The comparative sample explosive unit produced an 18.5 centimeter (7.28 inch) swell, but the jetting caused by the explosive material and liners undesirably penetrated the inside diameter of the test pipe. Samples “A” and “B” resulted in 19.3 centimeter (7.6 inch) and 18.6 centimeter (7.32 inch) swells (protrusions), respectively, that were smooth and uniform around the inner diameter of the test pipe.
A second test was performed using the Sample “A” explosive unit in a test pipe having similar properties as in the first series of tests, but this time with an outer housing outside the test pipe to see how the character of the swell in the test pipe might change and whether a seal could be effected between the test pipe and the outer housing. The test pipe had a 17.8 centimeter (7 inch) outer diameter, a 16.1 centimeter (6.32 inch) inner diameter, a 0.86 centimeter (0.34 inch) wall thickness, and a 813.6 Mpa (118 KSI) tensile strength. The outer housing had an 21.6 centimeter (8.5 inch) outer diameter, a 18.9 centimeter (7.4 inch) inner diameter, a 1.35 centimeter (0.53 inch) wall thickness, and a 723.95 Mpa (105 KSI) tensile strength.
The second test was conducted at ambient temperature with the following conditions. Pressure: 20.7 Mpa (3,000 psi). Fluid: water. Centralized Shooting Clearance: 0.09 centimeters (0.04 inches). Clearance between the 17.8 centimeter (7 inch) outer diameter of the test pipe and the inner diameter of the housing: 0.55 centimeters (0.22 inches). After the sample “A” explosive unit was detonated, the swell on the 17.8 centimeter (7 inch) test pipe measured at 18.9 centimeters (7.441 inches)×18.89 centimeters (7.44 inches), indicating that the inner diameter of the outer housing (18.88 centimeters (7.433 inches)) somewhat retarded the swell (19.3 centimeters (7.6 inches)) observed in the first test series involving sample “A”. There was thus a “bounce back” of the swell caused by the inner diameter of the outer housing. In addition, the inner diameter of outer housing increased from 18.88 centimeters (7.433 inches) to 18.98 centimeters (7.474 inches). The clearance between the outer diameter of the test pipe and the inner diameter of the outer housing was reduced from 0.55 centimeters (0.22 inches) to 0.08 centimeters (0.03 inches).
A second series of tests was performed to compare the performance of a shaped charge tool 10 (with liner-less explosive units 60) having different explosive unit load weights. In the second series of tests, the goal was to maximize the expansion of a 17.8 centimeter (7 inch) outer diameter pipe having a wall thickness of 1.37 centimeters (0.54 inches), to facilitate operations on a Shell North Sea Puffin well. Table 2 shows the results of the tests.
Tests #1 to #3 used the shaped charge tool 10 having liner-less explosive units 60 with progressively increasing explosive weights. In those tests, the resulting swell of the 17.8 centimeter (7 inch) outer diameter pipe continued to increase as the explosive weight increased. However, in test #3, which utilized 350 grams (12.35 ounces) HMX resulting in a 204 gram (7.2 ounces) unit loading, the focused energy of the expansion charged breached the 17.8 centimeter (7 inch) outer diameter pipe. Thus, to maximize the expansion of this pipe without breaching the pipe would require the amount of explosive energy in test #3 to be delivered with less focus.
Returning to the method discussed above, the relatively short expansion length (e.g., 10.2 centimeters (4 inches)) may advantageously seal off micro annulus leaks or cure the other cement defects discussed herein. It may be the case that the cement density between the outer diameter of the inner tubular T1 and the inner diameter of the outer tubular T2 was inadequate to begin with, such that a barrier may not be formed and/or the cement “C” present between the inner tubular T1 and the outer tubular T2 may simply be forced above and below the expanded protrusion “P” (see, e.g.,
Multiple explosive units 60 can be selectively detonated at different times while the tool 10, such as shown in
The contingencies discussed with respect to
In the methods discussed above, expansion of the inner tubular T1 causes the sealant displaced by the expansion to compress, reducing the number of micro pores in the cement or the number of other cement defects discussed herein. The expansion may occur after the sealant is pumped into the annulus “A”. Alternatively, the cement or other sealant may be provided in the annulus “A” on the portion of the wall of the inner tubular T1, after the portion of the wall is expanded. The methods may include selectively expanding the inner tubular T1 at a second location spaced from the first location to create a pocket between the first and second locations. The sealant may be provided in the annulus “A” before the pocket is formed. In an alternative embodiment, expansion at the first location may occur before the sealant is provided, and expansion at the second location may occur after the sealant is provided.
The reduced number of pores, channels, or other cement imperfections allowing annulus leaks in the compressed cement “CC”, “CC2” reduces the risk of seepage into the cement and helps seal against annulus flow through the consolidated cement. Further, the protrusions “P”, “P2” may create a ledge or barrier that helps seal that portion of the wellbore from seepage of outside materials. The size and shape of the protrusions “P”, “P2” may vary depending on several factors, including, but not limited to, the size (e.g., thickness), strength and material of the inner and outer tubulars T1, T2, the type and amount of the explosive material, the hydrostatic pressure bearing on the inner and outer tubulars T1, T2, the desired size of the protrusions “P” “P2”, and the nature of the wellbore operation.
The reduced number of pores, channels, or other cement imperfections allowing annulus leaks in the compressed cement “CC”, “CC2” and “CC3” reduces the risk of seepage into the cement and helps seal against annulus flow through the consolidated cement. Further, the protrusions “P”, “P2” and “P3” may create a ledge or barrier that helps seal that portion of the wellbore from seepage of outside materials. The size and shape of the protrusions “P”, “P2” and “P3” may vary depending on several factors, including, but not limited to, the size (e.g., thickness), strength and material of the tubulars T1, 12 and T3, the type and amount of the explosive material, the hydrostatic pressure bearing on the tubulars T1, T2 and T3, the desired size of the protrusions “P”, “P2” and “P3”, and the nature of the wellbore operation.
For illustrative simplicity in
A variation of the shape charge tool 10 is illustrated in
Original initiation of the
Significantly, the conically tapered aperture 80 of
The variation of the tool 10 shown in
The
Transporting and storing the explosive units may be hazardous. There are thus safety guidelines and standards governing the transportation and storage of such. One of the ways to mitigate the hazard associated with transporting and storing the explosive units is to divide the units into smaller component pieces. The smaller component pieces may not pose the same explosive risk during transportation and storage as a full-size unit may have. Each of the explosive units 60 discussed herein may thus be provided as a set of units that can be transported unassembled, where their physical proximity to each other in the shipping box would prevent mass (sympathetic) detonation if one explosive component was detonated, or if, in a fire, would burn and not detonate. The set is configured to be easily assembled at the job site.
In the illustrated embodiment, the smaller area first surface 106 of the first explosive unit 102 includes a recess 116, and the smaller area first surface 108 of the second explosive unit 104 comprises a protrusion 118. The first explosive unit 102 and the second explosive unit 104 are configured to be connected together with the smaller area first surface 106 of the first explosive unit 102 facing the second explosive unit 104, and the smaller area first surface 108 of the second explosive unit 104 facing the smaller area first surface 106 of the first explosive unit 102. The protrusion 118 of the second explosive unit 104 fits into the recess 116 of the first explosive unit 102 to join the first explosive unit 102 and the second explosive unit 104 together. The first explosive unit 102 and the second explosive unit 104 can thus be easily connected together without using tools or other materials.
In the embodiment, the protrusion 118 and the recess 116 have a circular shape in planform, as shown in
Referring back to
In the embodiment shown in
In one embodiment, the explosive unit 300 may have a diameter of about 8.38 centimeters (3.3 inches).
The set of segments is configured to be easily assembled at the job site. Thus, a method of selectively expanding at least a portion of a wall of a tubular at a well site via a shaped charge tool 10 may include first receiving an unassembled set of explosive units 300 at the well site, wherein each explosive unit 300 comprising explosive material, is divided multiple segments 301, 302, 303 that, when joined together, form an explosive unit 300. The method includes assembling the tool 10 (see, e.g.,
In another embodiment shown by
Another embodiment of the centralizer assembly is shown in
The multiple attachment points 344a, 344b on each blade 345, being spaced laterally from each other, prevent the unintentional rotation of individual blades 345, even in the event that the fasteners 342 are slightly loose from the attachment points 344a, 344b. The fasteners 342 can be of any type of fastener usable for securing the blades into position, including screws. The blades 345 can be spaced laterally and oriented perpendicular to each other, for centralizing the tool 10 and preventing unintentional rotation of the one or more blades 345.
While the disclosure above discusses embodiments in which there is no liner on the exterior surface 50 of the explosive units 60 (i.e., the exterior surface 50 of the explosive units 60 is exposed to the inner surface 51 of the housing 20), alternative embodiments of the present disclosure may include a liner 50a on the exterior surface of the explosive units 60, as shown in
On the other hand, a liner formed of a relatively low density and brittle material would not jet as well as the conventional materials discussed above. The present inventor has determined that a formed of a material that is less dense and ductile than copper, nickel, zinc, zinc alloy, iron, tin, bismuth, and tungsten, individually or in combination, (i.e., formed of a material that is brittle and has low density), may be effective in expanding, without puncturing, the wall of the tubular T1 to form the protrusion “P” discussed herein. In this regard, an embodiment of the liner 50a may have a density of 6 g/cc or less, and may be less ductal than copper, nickel, zinc, zinc alloy, iron, tin, bismuth, and tungsten, individually or in combination. In an embodiment, the liner 50a may be formed of glass material. In another embodiment, the liner 50a may be formed of a plastic material.
Another way to reduce the potency of the liner jet, so that the jet may expand, without puncturing, the wall of the tubular T1 to form the protrusion “P” discussed herein, is to perforate the liner 50a. In addition, or in the alternative, the liner 50a may be formed so that a density, wall thickness, and/or composition of the liner 50a is asymmetric around at least one of the explosive units 60. In addition, or in the alternative, the explosive units 60 may be formed so that a density, wall thickness, and/or composition of the explosive units 60 is asymmetric around at least one of the explosive units 60. Further, the liner 50a of at least one of the explosive units 60 may be geometrically asymmetric. Asymmetric explosive units 60 may reduce the potency of explosive units 60 so that detonation of the explosive units 60 may expand, without puncturing, the wall of the tubular T1 to form the protrusion “P” discussed herein. Similarly, asymmetric liners may reduce the potency of the jet formed by the liners, so that the jet may expand, without puncturing, the wall of the tubular T1 to form the protrusion “P” discussed herein.
One or more puncher charges (not shown) may be inserted into the tubular 501 and actuated to punch holes 507 in the wall of the tubular 501 at a location uphole of the plug 506, as shown in
A more successful method of reducing a leak 505 in the annulus 502 adjacent a tubular 501 in a wellbore 500 is shown in
In particular, one or more puncher charges (not shown) may be subsequently inserted into the tubular 501 and actuated to punch holes 507 in the wall of the tubular 501 as shown in
In the embodiments discussed above, expansion tools including one or more expansion charges have been discussed. The expansion charges may be shaped charges as discussed above. However, a dual end firing tool or single end firing tool may also be used to expand, without puncturing, the wall of the tubular to form a protrusion extending outward into the annulus adjacent the wall of the tubular as discussed herein. Dual end fired and single end fired cylindrical explosive column tools (e.g., modified pressure balanced or pressure bearing severing tools) produce a focused energetic reaction, but with much less focus than from shaped charge expanders. In dual end fired explosive column tools, the focus is achieved via the dual end firing of the explosive column, in which the two explosive wave fronts collide in a middle part of the column, amplifying the pressure radially. In single end fired explosive column tools, the focus is achieved via the firing of the explosive column from one end which generates one wave front producing comparatively less energy. The single wave front may form a protrusion in the wall of the tubular, without perforating or cutting through the wall. The protrusion formed by a single end fired explosive column tool may be asymmetric as compared with a protrusion formed by a dual end fired explosive column tool. The length of the selective expansion in both types of explosive column tools is a function of the length of the explosive column, and may generally be about two times the length of the explosive column. With a relatively longer expansion length, for example, 40.64 centimeters (16.0 inches) as compared to a 10.16 centimeter (4.0 inch) expansion length with a shaped charge explosive device, a much more gradual expansion is realized. The more gradual expansion allows a greater expansion of any tubular or pipe prior to exceeding the elastic strength of the tubular or pipe, and failure of the tubular or pipe (i.e., the tubular or pipe being breeched).
An embodiment of an expansion tool 600 for selectively expanding at least a portion of a wall of a tubular is shown in
The dual end firing explosive column tool 600 can be arranged to serially align a plurality of high explosive pellets 640 along a central tube to form an explosive column. The pellets 640 may be pressed at forces to keep well fluid from migrating into the pellets 640. In addition, or in the alternative, the pellets 640 may be coated or sealed with glyptal or lacquer, or other compound(s), to prevent well fluid from migrating into the pellets 640. The dual end firing explosive column tool 600, as shown, is provided without an exterior housing so that the explosive pellets 640 can be exposed to an outside of the dual end firing explosive column tool 600, meaning that there is no housing of the dual end firing explosive column tool 600 covering the pellets 640. That is, when the dual end firing explosive column tool 600 is inserted into a pipe or other tubular, the explosive pellets 640 can be exposed to an inner surface of the pipe or other tubular. Alternatively, a sheet of thin material, or “scab housing” (not shown) may be provided with the dual end firing explosive column tool 600 to cover the pellets 640, for protecting the explosive material during running into the well. The material of the “scab housing” can be thin enough so that its effect on the explosive impact of the pellets 640 on the surface of the pipe or other tubular is immaterial. Moreover, the explosive force can vaporize or pulverize the “scab housing” so that no debris from the “scab housing” is left in the wellbore. In some embodiments, the “scab housing” may be formed of Teflon, PEEK, ceramic materials, or highly heat treated thin metal above 40 Rockwell “C”. Bi-directional detonation boosters 624, 626 are positioned and connected to detonation cords 630, 632 for simultaneous detonation at opposite ends of the explosive column. Each of the pellets 640 can comprise about 22.7 grams (0.801 ounces) to about 38.8 grams (1.37 ounces) of high order explosive, such as RDX, H MX or HNS. The pellet density can be from, e.g., about 1.6 g/cm3 (0.92 oz/in3) to about 1.65 g/cm3 (0.95 oz/in3), to achieve a shock wave velocity greater than about 9,144 meters/sec (30,000 ft/sec), for example.
A shock wave of such magnitude can provide a pulse of pressure in the order of 27.6 Gpa (4×106 psi). It is the pressure pulse that expands the wall of the tubular. The pellets 640 can be compacted at a production facility into a cylindrical shape for serial, juxtaposed loading at the jobsite, as a column in the dual end firing explosive column tool 600. The dual end firing explosive column tool 600 can be configured to detonate the explosive pellet column at both ends simultaneously, in order to provide a shock front from one end colliding with the shock front to the opposite end within the pellet column at the center of the column length. On collision, the pressure is multiplied, at the point of collision, by about four to five times the normal pressure cited above. To achieve this result, the simultaneous firing of the bi-directional detonation boosters 624, 626 can be timed precisely in order to assure collision within the explosive column at the center. In an alternative embodiment, the expansion tool 600 may be a single end firing explosive column tool that includes a detonation booster at only one end of the explosive pellet column, so that the explosive column is detonated from only the one end adjacent the detonation booster, as discussed above, and so the configuration of the single end firing explosive column tool is similar to that of the dual end firing explosive column tool discussed herein.
Toward the upper end of the guide tube 616, an adjustably positioned partition disc 620 can be secured by a set screw 621. Between the partition disc 620 and the inside face 638 of the top sub 612 can be a timing spool 622, as shown in
To load the dual end firing explosive column tool 600, the guide tube terminal 618 can be removed along with the resilient spacers 642 (See
The pellets 640 can be loaded serially in a column along the guide tube 616 length with the first pellet 640, in juxtaposition against the lower face of partition disc 620 and in detonation proximity with the second bi-directional booster 628. The last pellet 640 most proximate of the terminus 618 is positioned adjacent to the first window aperture 634. The number of pellets 640 loaded into the dual end firing explosive column tool 600 can vary along the length of the tool 600 in order to adjust the size of the shock wave that results from igniting the pellets 640. The length of the guide tube 616, or of the explosive column formed by the pellets, may depend on the calculations or testing discussed below. Generally, the expansion length of the wall of the tubular can be about two times the length of the column of explosive pellets 640. In testing performed by the inventor, a 19.1 centimeters (7.5 inch) column of pellets 640 resulted in an expansion length of the wall of a tubular of 40.6 centimeters (16 inches) (i.e., a ratio of column length to expansion length of 1 to 2.13). Any space remaining between the face of the bottom-most pellet 640 and the guide tube terminal 618 due to fabrication tolerance variations may be filled, e.g., with resilient spacers 642.
A method of selectively expanding at least a portion of the wall of a pipe or other tubular using the expansion tool described herein may be as follows. The expansion tool may be either the modified pressure balanced tool 600 of
As shown in
The protrusion “P” may impact the inner wall of outer tubular T2 after detonation of the explosive pellets 640. In some embodiments, the protrusion “P” may maintain contact with the inner wall of the outer tubular T2 after expansion is completed. In other embodiments, there may be a small space between the protrusion “P” and the inner wall of the outer tubular T2. Expansion of the tubular T1 at the protrusion “P” can cause that portion of the wall of the tubular T1 to be work-hardened, resulting in greater strength of the wall at the protrusion “P”.
Embodiments of the methods of the present invention show that the portion of the wall having the protrusion “P” is not weakened. In particular, the yield strength of the tubular T1 increases at the protrusion “P”, while the tensile strength of the tubular T1 at the protrusion “P” decreases only nominally. Therefore, according to these embodiments, expansion of the tubular T1 at the protrusion “P” thus strengthens the tubular without breaching the tubular T.
The magnitude of the protrusion “P” can depend on several factors, including the length of the column of explosive pellets 640, the outer diameter of the explosive pellets 640, the amount of explosive material in the explosive pellets 640, the type of explosive material, the strength of the tubular T1, the thickness of the wall of the tubular T1, the hydrostatic force bearing on the tubular T1, and the clearance adjacent the tubular T1 being expanded, i.e., the width of the annulus “A” adjacent the tubular T1 that is to be expanded.
One way to manipulate the magnitude of the protrusion “P” is to control the amount of explosive force acting on the pipe or other tubular member T1. This can be done by changing the number of pellets 640 aligned along the guide tube 616. For instance, the explosive force resulting from the ignition of a total of ten pellets 640 is larger than the explosive force resulting from the ignition of a total of five similar pellets 640. As discussed above, the length “LI” (see
The above method of selectively expanding at least a portion of a wall of the tubular T1 via an expansion tool may be modified to include determining the following characteristics of the tubular T1: a material of the tubular T1: a thickness of a wall of the tubular T1; an inner diameter of the tubular T1; an outer diameter of the tubular T1; a hydrostatic force bearing on the tubular T1; and a size of a protrusion “P” to be formed in the wall of the tubular T1. Next, the explosive force necessary to expand, without puncturing, the wall of the tubular T1 to form the protrusion “P”, is calculated, or determined via testing, based on the above determined material characteristics.
The determinations and calculation of the explosive force can be performed via a software program, and providing input, which can then be executed on a computer. Physical hydrostatic testing of the explosive expansion charges yields data which may be input to develop computer models. The computer implements a central processing unit (CPU) to execute steps of the program. The program may be recorded on a computer-readable recording medium, such as a CD-ROM, or temporary storage device that is removably attached to the computer. Alternatively, the software program may be downloaded from a remote server and stored internally on a memory device inside the computer. Based on the necessary force, a requisite number of explosive pellets 640 to be serially added to the guide tube 616 of the expansion tool is determined. The requisite number of explosive pellets 640 can be determined via the software program discussed above.
The requisite number of explosive pellets 640 is then serially added to the guide tube 616. After loading, the loaded expansion tool can be positioned within the tubular T1, with the last pellet 640 in the column being located adjacent the detonation window 634. Next, the expansion tool can be actuated to ignite the pellets 640, resulting in a shock wave as discussed above that expands the wall of the tubular T1 radially outward, without perforating or cutting through the wall, to form the protrusion “P”. The protrusion “P” can extend into the annulus “A” between an outer surface of the tubular T1 and an inner surface of a wall of another tubular T2.
In a test conducted by the inventors using the dual end firing explosive column tool 600 to radially expand a pipe having a 6.4 centimeter (2.5 inch) wall thickness, an inner diameter of 22.9 centimeters (9.0 inches) and an outer diameter of 35.6 centimeters (14.0 inches), the expansion resulted in a radial protrusion measuring 45.7 centimeters (18.0 inches) in diameter. That is, the outer diameter of the pipe increased from 35.6 centimeters (14.0 inches) to 45.7 centimeters (18.0 inches) at the protrusion. The protrusion is a gradual expansion of the wall of the tubular T1. The more gradual expansion allows a greater expansion of the tubular T1 prior to exceeding the elastic strength of the tubular T1, and failure of the tubular T1 (i.e., the tubular being breeched).
The column of explosive pellets 640 can comprise a predetermined (or requisite) amount of explosive material sufficient to expand at least a portion of the wall of the pipe or other tubular into a protrusion extending outward into an annulus adjacent the wall of the pipe or other tubular. It is important to note that the expansion can be a controlled outward expansion of the wall of the pipe or other tubular, which does not cause puncturing, breaching, penetrating or severing of the wall of the pipe or other tubular. The annulus may be reduced between an outer surface of the wall of the pipe or other tubular and an outer wall of another tubular or a formation.
The protrusion “P” creates a ledge or barrier into the annulus that helps seal that portion of the wellbore during plug and abandonment operations in an oil well. For instance, a sealant, such as cement or other sealing material, mud and/or debris, may exist in the annulus “A” on the ledge or barrier created by the protrusion “P”. The embodiments above involve using one column of explosive pellets 640 to selectively expand a portion of a wall of a tubular into the annulus. One option is to use two or more columns of explosive pellets 640. The explosive columns may be spaced at respective expansion lengths which, as noted previously, can vary as a function of the length of the explosive column unique to each application. After the first protrusion is formed by the first explosive column, the additional explosive column is detonated at a desired location, to expand the wall of the tubular T1 at a second location that is spaced from the first location and in a direction parallel to an axis of the expansion tool, to create a pocket outside the tubular T1 between the first and second locations. The pocket is thus created by sequential detonations of explosive columns. In another embodiment, the pocket may be formed by simultaneous detonations of explosive columns. For instance, two explosive columns may be spaced from each other at first and second locations, respectively, along the length of the tubular T1. The two explosive columns are detonated simultaneously at the first and second locations to expand the wall of the tubular T1 at the first and second locations to create the pocket outside the tubular T1, between the first and second locations.
Whether one or multiple columns of explosive pellets 640 are utilized, the method may further include setting a plug 19 below the deepest selective expansion zone, and then shooting perforating puncher charges through the wall of the inner tubular T1 above the top of the shallowest expansion zone, so that there can be communication ports 21 from the inner diameter of the inner tubular T1 to the annulus “A” between the inner tubular T1 and the outer tubular T2, as shown in
The methods discussed herein have involved selectively expanding a wall of tubular while the tubular is inside of a wellbore. A variation of the embodiments discussed herein includes a method of selectively expanding a wall of tubular outside of the wellbore before the tubular is inserted into the wellbore. This variation may be carried out with the various expansion tools discussed herein. The various expansion tools discussed herein can be used to selectively expand the wall of tubular outside of the wellbore. The amount of explosive material used in this variation may be based upon the physical aspects of the tubular, the nature and conditions of the wellbore in which the tubular will subsequently be inserted, and upon the type of function the selectively expanded tubular is to perform in the wellbore. The selective expansion of the tubular may occur, for example, at a facility offsite from the location of the actual wellbore. The selectively expanded tubular may be inspected to confirm dimensional aspects of the expanded tubular, and then be transported to the wellsite for insertion into the wellbore. For instance, a method of selectively expanding a wall of a tubular may involve positioning an expansion tool within the tubular, wherein the expansion tool contains an amount of explosive material for producing an explosive force sufficient to expand, without puncturing, the wall of the tubular. Next, the expansion tool may be actuated to expand the wall of the tubular radially outward, without perforating or cutting through the wall of the tubular, to form a protrusion that extends outward from the central bore of the tubular. The selectively expanded tubular may then be subsequently inserted into a wellbore.
Because wellbore conditions and the physical properties of the tubular within the wellbore vary from wellbore to wellbore, it may be desirable to tailor the physical or compositional make-up (e.g., type, amount, size) of an expansion charge to the specific tubular and conditions in the wellbore at which the expansion charge is to be used. Pre-testing expansion charges to be deployed based on the specific conditions that exist in a wellbore and/or physical properties of the tubular in the wellbore is helpful to ensure beforehand that the expansion charge will provide an adequate or desired wall expansion (e.g., protrusion) of the wellbore tubular, without perforating or cutting through, when the expansion charge is actuated in the wellbore.
In this regard, the pre-testing system 700 may be used to simulate or reproduce conditions that exist in the onsite wellbore, namely the hydrostatic pressure and the fluid/gas medium present, so that the tested expansion charge 705 can be designed and manufactured to have a similar or the same effect when used on a tubular in the onsite wellbore. For instance, the pressure vessel 701 may be filled with air, water, nitrogen, drilling fluid, completion fluid, acidizing fluid, salt water, and/or fresh water to match or represent the environment (e.g., air, water, nitrogen, drilling fluid, completion fluid, acidizing fluid, salt water, and/or fresh water) that exists in onsite wellbore. The autoclave high pressure pump 709 may then pressurize the pressure vessel 701 (e.g., using the same material) to a hydrostatic pressure that exists at a depth in the onsite wellbore where the wall of the wellbore tubular is to be expanded. In addition, the physical characteristics the test tubular 704 may, in some cases, be the same or similar to those of the actual tubular in the onsite wellbore. In a preferred embodiment, a new tubular having the same or similar physical characteristics, such as material type, size, grade, weight, wall thickness, outer diameter, and inner diameter, to the actual tubular in the onsite wellbore may be used as the test tubular 704. As an example, test tubular 704 may be a 5.5 inch outer diameter, 0.244 inch thick, 14.0 ppf, J-55 tubular. In addition, the pre-testing system 700 may be used under conditions that are transferrable to a downhole application. For instance, pre-testing in a pressure vessel 701 or in a water tank or open water with different conditions than exist downhole in the onsite wellbore can produce results that, with manipulation to the design of the expansion charge 705 or other conditions based on the test results, can transferred to the downhole application. That is, the manipulated expansion charge or other conditions can have the same or similar effect, or other desired effect, when used on a tubular in the onsite wellbore of the downhole application.
The pre-testing system 700 illustrated in
The pre-testing systems 700, 700A discussed above may be used to implement a method of determining an expansion charge able to selectively expand, without perforating or cutting through, a portion of a wall of a tubular in an onsite wellbore. The method may include determining conditions in the onsite wellbore. The conditions may include, among other things, the fluid/gas medium in the wellbore, hydrostatic pressure bearing on the tubular in the onsite wellbore, and at least one physical characteristic of the tubular. For instance, the method may include determining whether the fluid/gas medium in the onsite wellbore comprises air, water, nitrogen, drilling fluid, completion fluid, acidizing fluid, salt water, fresh water and/or combinations thereof. The determined conditions may be reproduced, simulated, accounted for, or otherwise factored into the pre-testing systems 700, 700A discussed herein. As an example, if the fluid/gas medium in the onsite wellbore includes acidizing fluid, then the pressure vessel 701 may be filled with acidizing fluid to help simulate in the pressure vessel 701 the conditions existing in the onsite wellbore. Physical characteristics of the tubular in the onsite wellbore that may be determined can include the material of the tubular, the grade, the weight, the inner diameter, and the outer diameter. The test tubular 704 in the pre-testing systems 70), 700A may have the same or similar physical characteristics as the actual tubular in the onsite wellbore, and may be new. In some embodiments, the test tubular 704 in the pre-testing systems 700, 700A may be a used tubular from the onsite wellbore, if available. As discussed above, using a new tubular in the “unconfined” testing system 700 may serve as a safety factor against breaching the actual tubular in the onsite wellbore because if the expansion charge 705 does not rupture the new test tubular 704, then the same expansion charge 705 should not rupture the actual tubular in the onsite wellbore, which actual tubular will likely have at least some confinement (or greater pressure), so long as the mechanical properties of the actual tubular are not significantly reduced by corrosion, etc.
When the pressure acting on the tubular in the onsite wellbore is relatively low, for example, less than or equal to 5000 psi, the method may involve providing the test tubular 704 in the “confined” pre-testing system 700A configuration discussed above. This may be the case for onsite wellbores having a gaseous environment, such a nitrogen, or gases having a similar atomic weight as nitrogen. As discussed above, the test tubular 704 in the “confined” pre-testing system 700A may be encased in the pressure vessel 701 with a material 710 such as cement, sand, or other material that encases the actual tubular in the onsite wellbore. That is, the annulus adjacent an outer surface of the test tubular 704 contains a solid material, such as cement, sand, or other material that encases the actual tubular in the onsite wellbore. Further, the material 710 may be surrounded by a second tubular 711 as discussed above. When the pressure acting on the tubular in the onsite wellbore is greater than 5000 psi, the method may involve providing the test tubular 704 in the “unconfined” pre-testing system 700 configuration discussed above. In that case, the test tubular 704 may be unconfined such that the outer surface of the test tubular 704 is exposed to the fluid/gas medium within the pressure vessel 701. That is, the annulus adjacent the outer surface of the test tubular 704 contains no solid material, rather than being encased in cement, sand, another solid material, and/or another tubular, in the pressure vessel 701.
In some cases, the method may include determining beforehand the size of a protrusion to be formed in the wall of the tubular in the onsite wellbore. This determination may be based on the type of the onsite wellbore and/or the oilfield job (e.g., plug and abandon) to be performed on tubular in the onsite wellbore. Knowing beforehand the size of the protrusion to be formed in the wall of the tubular may help determine the size, explosive gram weight, material, and/or other physical characteristic discussed herein of the expansion charge 705 to be used in the pre-testing systems 700, 700A, and eventually in the tubular of the onsite wellbore. For instance, relatively larger protrusions may require a relatively larger size and higher explosive gram weight expansion charge. The expansion charge 705 may be a shaped charge for use in a shaped charged expansion tool, and may comprise embodiments of the shaped charges discussed herein. For relatively larger tubulars (i.e., having thicker walls), and/or multiple nested pipes, a dual-end firing explosive column tool may be used.
The method further includes determining a test expansion charge 705 that is able to expand, without perforating or cutting through, the wall of the test tubular 704, based on at least one of the conditions determined in the wellbore. In some embodiments, determining a test expansion charge 705 may include determining a size and an explosive gram weight of test expansion charge 705 that is able to expand, without perforating or cutting through, the wall of the test tubular 704. Determining a test expansion charge 705 may also include determining a shape, or other characteristic of expansion charges discussed herein. In some embodiments, these determinations may be made based on tests, or a history of tests, that are conducted in trial-and-error processes. For instance, a record of tests (such as Tests #1 to #16 discussed below) can be stored in a library of test data used to forecast or predict expansion results. The record may include test results that are organized and/or retrievable according to wellbore type, wellbore conditions, oilfield job type, tubular size and type, expansion charge type, expansion charge size, expansion charge explosive gram weight, type of explosive material, and other characteristic discussed herein. The test expansion charge 705 may be determined by reviewing the library of test data and focusing on a test result having one or more similar conditions (e.g., with respect to the fluid/gas medium in the wellbore, hydraulic pressure in the wellbore, and physical characteristics of the tubular in the wellbore, among other conditions discussed herein) as the onsite wellbore for which the test expansion charge 705 is being designed.
Once the test expansion charge 705 is determined, the test expansion charge 705 may be positioned within the test tubular 704 in the pressure vessel 701. The test expansion charge 705 is then actuated, in a manner discussed herein, to expand the wall of the test tubular 704 radially outward, without perforating or cutting through the wall of the test tubular 704, to form a test protrusion in the wall of the test tubular 704. Depending on the size, shape or other physical characteristic of the test protrusion, the test expansion charge 705 may be selected as the expansion charge for expanding, without perforating or cutting through, the portion of the wall of the actual tubular in the onsite wellbore. Or, if the size, shape or other physical characteristic of the test protrusion was determined to be a failure (e.g., a breach of the tubular on one hand or not enough expansion on the other hand), a different expansion charge may be selected for expanding, without perforating or cutting through, the portion of the wall of the actual tubular in the onsite wellbore. As discussed above, the test expansion charge 705 may be selected based on a particular size and/or explosive gram weight of the test expansion charge 705, or on another characteristic of the test expansion charge 705 evident from testing the test expansion charge. In some embodiments, a particular size and/or explosive gram weight for the actual expansion charged used to expand the actual tubular in the onsite wellbore may be selected based on the performance of the test expansion charge 705. The methods discussed above may further include, using the principles discussed above, determining a test expansion charge 705 that is able to expand, without perforating or cutting through, both the wall of the test tubular 704 and the wall of the second tubular 711, with a single actuation of the test expansion charge 705, to provided nested protrusions as discussed with respect to
The following describes some tests that were conducted by the inventor to determine an expansion charge able to expand, without perforating or cutting through, the wall of a particular tubular. Specifically, Tests #1 to #16 were conducted to determine the size (e.g., outer diameter. “O.D.”) and explosive gram weight required in an expansion charge to expand a 3.5 inch O.D., 9.20 ppf. L-80 tubular to the targeted diameter of 4.000 inch in different environments (e.g. air, water, nitrogen). The sizes (O.D.) and explosive gram weights of the expansion charges that were tested were: (a) 2.188 inch O.D.; 34-50 grams HMX; and (b) 2.125 inch O.D.; 22-40 grams HMX. The target expansion diameter for the 3.5 inch O.D. tubular was 0.25 inches on the radius. The tests were conducted in ambient temperature. A 10 foot pressure vessel and a 42 inch pressure vessel were used in the tests. The set up for each pressure vessel was as follows:
The 10 foot pressure vessel: (a) 14 inch O.D.×9 inch I.D.×10 foot long, P110 pressure vessel; (b) 3.5 inch O.D.×0.254 inch wall thickness, 9.2 ppf, L-80 target tubular, 4 foot long positioned mid vessel and centralized; (c) 2.188 inch or 2.125 inch expansion charge centralized in the middle of the 3.5 inch O.D, tubular: (d) 102 inch working length inside the of the pressure vessel; and (e) junk baskets that were (i) 8⅝ inch O.D.×8 inch I.D.×8 feet long; and (ii) 8-⅝ inch O.D.×6 inch I.D.×8 feet long.
The 42 inch pressure vessel: (a) 14 inch O.D.×9 inch I.D.×42 inch long, P110 pressure vessel; (b) 3.5 inch O.D.×0.254 inch wall thickness, 9.2 ppf, L-80 target tubular, 24 inches long positioned mid vessel and centralized; (c) 2.125 inch expansion charge centralized in the middle of the 3.5 inch O.D. tubular: (d) 24 inch working length inside the vessel; and (e) junk baskets that were (iii) 8⅝ inch O.D.×6 inch I.D.×24 inches long; and (iv) 8⅝ inch O.D.×4½ inch I.D.×24 inches long.
To begin with, three pre-tests were conducted at 0 psi in a spent 14 inch O.D.×9 inch I.D.×10 foot long pressure vessel with a 2.188 inch expansion charge, with the following results.
The results of these tests show that at 0 psi in water (Test #2), the test tubular was expanded to 4.196 inches O.D. In addition, the 14 inch×9 inch×10 foot long reusable vessel can be used to conduct the 1,000 psi nitrogen test, as the vessel stayed intact during Test #3 (0 psi in air). Test #3 showed that the 34 gram, 2.188 inch expansion charge breached (i.e., split) the tubular such that the expansion “failed”. Loading a smaller expansion charge, for example, a 2.125 inch expansion, with 18 grams to 22 grams of explosive, instead of 34 grams, may reach the target expansion at 1,000 psi in nitrogen. Further tests were conducted to optimize the expansion in air at 0 psi with a 2.125 inch expansion charge and different explosive gram weights.
These test results show that the 3.838 inch O.D. expansion in air at 0 psi is not far from the 4.000 inch expansion target, but not so close to the 4.196 inch O.D. expansion achieved when tested in water at 0 psi. It is noted that water as the atmosphere offers some confinement and would slow down the speed of the pressure wave front of the expansion charge. More tests were conducted, this time with a nitrogen atmosphere at 1,000 psi and with a 24 gram expansion charge, with the following results.
Test #8 was conducted in the shorter 42 inch pressure vessel in order to minimize the volume of nitrogen, and the expansion failed. Test #9 was conducted in the 10 foot pressure vessel, and the expansion was similar to the expansion in Test #6 in air at 0 psi. Test #10 was conducted in the 42 inch pressure vessel with a 4.5 inch I.D. junk basket, and the expansion also failed. In Test #11, the 25 gram weight expansion charge failed in nitrogen at 0 psi.
Tests #12 to #16 were conducted with the 3½″ inch target tubular cemented, with Portland cement (100/44 cement to water ratio), inside of 7 inch O.D.×6.526 inch I.D.×4 foot long. 26 ppf, L-80 tubular. No significant voids existed in the cement as the 4 foot targets were poured in the vertical position. After the test shots the 7 inch O.D. outer tubular was cut off with a torch to retrieve the 3½″ O.D. tubular for measurements. After the test shots, the 7 inch O.D. outer tubular showed no expansion. On each end the cement in the annulus had extruded around ⅛ inches.
The above described test procedures and processes may be helpful in determining beforehand, based on the specific conditions that exist in a wellbore and/or physical properties of the tubular set in the onsite wellbore, a specific expansion charge that is to be used on the tubular in that onsite wellbore. A specific expansion charge can be designed based on those conditions to ensure that the expansion charge sufficiently expands, without perforating or cutting through, the wall of the tubular in the onsite wellbore. As the actual conditions determined in the onsite wellbore can be simulated, reproduced, factored in, or otherwise accounted for, the above-described pre-testing may help ensure that the expansion charge provides an adequate or desired wall expansion (e.g., protrusion) of the wellbore tubular when the expansion charge is actuated in the onsite wellbore.
The pre-testing discussed above with respect to
As a result of the single detonation of the 1.750 inch (outer diameter) by 9 inch long explosive column, protrusion P1 was formed in the wall of the innermost tubular T1 without perforating or cutting through the innermost tubular T1.
As a result of the single detonation of the 2.000 inch (outer diameter) by 9 inch long explosive column, protrusion P1 was formed in the wall of the innermost tubular T1, but the wall at the protrusion P1 was breached. This indicates a pre-testing failure with respect to the innermost tubular T1.
A second housing 820b may be spaced axially from the first housing 820a along a length of the explosive downhole tool 811, and a third housing 820c spaced axially from the second housing 820b along the length of the downhole tool 811, as shown in
The explosive downhole tool 811 further includes an intermediate guide 816 between the first housing 820a and the second housing 820b. Another intermediate guide 816 may be provided between the second housing 820b and the third housing 820c, as shown in
To improve the debris properties of the intermediate guide 816 and its component parts (e.g., the first intermediate guide portion 816a and fins 818 and the second intermediate guide portion 816b and fins 818), the intermediate guide 816 may in one embodiment be formed of a porous material. Examples of such material include, but are not limited to, cast iron or other sand casted metals, or other materials with relatively high porosity. The porosity of these materials weakens the strength of the materials so that the materials break more easily upon detonation of the explosive charges 860. These porous materials can be broken into granules or fine particles that result in very little debris, if any, that do not present an obstruction in the wellbore.
A method of cutting and/or selectively expanding a wall of a tubular using the explosive downhole tool 811 may include positioning the explosive downhole tool 811 within the tubular, and then actuating the explosive downhole tool 811 to ignite the explosive charges 860 causing shock waves that travel radially outward to impact the tubular, as discussed herein above.
A first intermediate connector 814 connects the first housing 820a to the second housing 820b, and a second intermediate connector 814 connects the second housing 820b to the third housing 820c. The intermediate connector 814 may have the shape of a hollow tube to accommodate components, such as a detonation cord, for igniting the explosive charge 860 in each of the second housing 820b and the third housing 820c. In another embodiment, the intermediate connector 814 may have another polygonal or geometric shape with an internal cavity to accommodate the components for igniting the explosive charge 860. The explosive downhole tool 810 may include a top sub 812 comprising components, such as a detonator, for igniting the explosive charges 860 as discussed herein above. The explosive charge 860 in the first housing 820a may be ignited by a detonating cord, a booster, or other mechanism for initiating ignition of the explosive charge 860. In an embodiment, the distance between the first housing 820a and the second housing 820b and between the second housing 820b and the third housing 820c is about 11.5 inches as measured between the center of the window section 824 (or apex of the explosive charge 860) had by each of the first, second and third housings 820a, 820b, 820c. However, the distance between the first housing 820a and the second housing 820b and between the second housing 820b and the third housing 820c is not particularly limiting, and may be more or less than about 11.5 inches. The length of the explosive downhole tool 810 as measured from the top end of the top sub 812 to the bottom of the third housing 820c may be about 29.5 inches, according to one embodiment. However, length of the downhole tool 810 as measured from the top end of the top sub 812 to the bottom of the third housing 820c may be more or less than 29.5 inches.
A primary difference between the explosive downhole tool 810 illustrated in
To improve the conveyance properties of the explosive downhole tool 810 within the wellbore, the outer surface of at least one of the upper housing part 821 and the lower housing part 822 is rounded or curved so as to be devoid of corners. In the embodiment shown in
In addition, the amount of debris produced by the explosive downhole tool 810 after detonation of the explosive charges 860 is greatly reduced or eliminated because there is little to no material outside of the housings 820a, 820b, 820c and intermediate connectors 814. That is, the explosive downhole tool 810 does not have the truss-like structure formed of web braces 935 between the housings 820a. 820b, 820c as found in conventional explosive downhole tools (see, e.g.,
Moreover, the debris properties of the explosive downhole tool 810 may be further improved by forming the intermediate connectors 814 of a dissolvable material that is designed to dissolve in brine solutions that are common in oil and gas wellbores. As an example, the dissolvable material may be a magnesium alloy, such as TervAlloy™ 3241 manufactured by Terves Inc. Each of the first, second and third housings 820a, 820b, 820c may also be formed of dissolvable material. The dissolvable material may be a magnesium alloy, such as TervAlloy™ 3241 manufactured by Terves Inc. Forming the intermediate connector 814 and/or first, second and third housings 820a, 820b, 820c of dissolvable material provides that very little to zero debris from intermediate connectors 814 and/or housings 820a, 820b, 820c remain in the well after detonation of the explosive charges 860. Whether or not the first, second and third housings 820a, 820b, 820c are formed of dissolvable material, the material of the housings may be formed of a reduced wall thickness that is frangible to break into relatively smaller pieces of debris.
A method of cutting and/or selectively expanding a wall of a tubular using the explosive downhole tool 810 may include positioning the explosive downhole tool 810 within the tubular, and then actuating the explosive downhole tool 811 to ignite the explosive charges 860 causing shock waves that travels radially outward to impact the tubular, as discussed herein above.
Because transporting and storing the explosive units 1000 may be hazardous, government regulations or other entities may limit the size of explosive units 1000 that can be transported in a vehicle and/or stored. One regulation limits the total mass of explosive units 1000 to 38.8 grams (600 grains) or less, which will historically pass United Nations Tests 6A to 6D. The United Nations Recommendations on the Transport of Dangerous Goods, which is incorporated herein by reference, provides Series 6 Tests used to determine which division, amongst Divisions 1.1, 1.2, 1.3, and 1.4, corresponds most closely to the behavior of the explosive product if a load is involved in a fire resulting from internal or external sources, or an explosion from internal sources. The Series 6 Tests also are incorporated herein by reference. The results of the Series 6 Tests assess whether the explosive product can be assigned to Division 1.4 and whether or not it should be excluded from Class 1. An assignment to Division 1.4 based on the Series 6 Tests meets safety criteria for transporting the explosive product. In other words, the United Nations Recommendations on the Transport of Dangerous Goods indicates that an explosive product can be safely transported if assigned to Division 1.4 based on the Series 6 Tests. However, it may be beneficial in some wellbore operations to provide explosive units 1000 that have a mass greater than 38.8 grams (600 grains), or that are outside the designation to Division 1.4 based on the Series 6 Tests (e.g., that are deemed too dangerous to transport according to the United Nations Recommendations on the Transport of Dangerous Goods. In this regard, the explosive unit 1000 of the present embodiment may be divided into two or more sections 1004 that are attachable to each other as shown in
The explosive unit 1000 may be provided as a set of sections 1004 that can be transported unassembled, where their physical proximity to each other in the shipping box would prevent mass (sympathetic) detonation if one explosive component was detonated, or if, in a fire, would burn and not detonate. The explosive unit 1000 could be easily assembled at the job site.
A method of assembling an explosive column tool with one or more of the explosive units 1000 may include receiving the explosive units 1000 that are each divided into the two or more sections 1004, attaching the two or more sections 1004 to each other, and loading the explosive unit(s) 1000 onto the explosive column. A method of actuating the loaded explosive column tool in a wellbore may include positioning the loaded explosive column tool within the wellbore, and actuating the explosive column tool to ignite the explosive unit(s) 1000.
In some embodiments, a sheet of thin material, or “scab housing” (not shown) may be provided to cover the explosive units 1000, for protecting the explosive units 1000 during running into the well. The material of the “scab housing”, which may be carbon fiber or phenolic, can be thin enough so that its effect on the explosive impact of the explosive units 1000 on the surface of the pipe or other tubular is immaterial. Moreover, the explosive force can vaporize or pulverize the “scab housing” so that no debris from the “scab housing” is left in the wellbore, or can fracture the “scab housing” so that the fractured debris from the “scab housing” can easily float in the wellbore. In some embodiments, the “scab housing” may be formed of Teflon, PEEK, ceramic materials, or highly heat treated thin metal above 40 Rockwell “C”.
Although several preferred embodiments have been illustrated in the accompanying drawings and describe in the foregoing specification, it will be understood by those of skill in the art that additional embodiments, modifications and alterations may be constructed from the principles disclosed herein. These various embodiments have been described herein with respect to selectively expanding a “pipe” or a “tubular.” Clearly, other embodiments of the tool of the present invention may be employed for selectively expanding any tubular good including, but not limited to, pipe, tubing, production/casing liner and/or casing. Accordingly, use of the term “tubular” in the following claims is defined to include and encompass all forms of pipe, tube, tubing, casing, liner, and similar mechanical elements.
The present application is a divisional of U.S. patent application Ser. No. 17/512,899 filed on Oct. 28, 2021, which, is a continuation-in-part of U.S. patent application Ser. No. 17/313,828 filed on May 6, 2021, which is a continuation-in-part of U.S. patent application Ser. No. 17/126,982 filed on Dec. 18, 2020, which is a continuation-in-part of U.S. patent application Ser. No. 16/970,602 filed on Aug. 17, 2020, which is a national phase of International Application PCT/US2019/046920 filed on Aug. 16, 2019, which claims priority to U.S. Provisional Patent Application No. 62/764,858 having a title of “Shaped Charge Assembly, Explosive Units, and Methods for Selectively Expanding Wall of a Tubular,” filed on Aug. 16, 2018. The contents of the prior applications are hereby incorporated by reference herein in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62764858 | Aug 2018 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17512899 | Oct 2021 | US |
| Child | 18371908 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 17313828 | May 2021 | US |
| Child | 17512899 | US | |
| Parent | 17126982 | Dec 2020 | US |
| Child | 17313828 | US | |
| Parent | 16970602 | Aug 2020 | US |
| Child | 17126982 | US |
