The present disclosure relates to an apparatus and method for rotationally orienting sections of a downhole tool.
Hydrocarbon producing wells typically include a casing string positioned within a wellbore that intersects a subterranean oil or gas deposit. The casing string increases the integrity of the wellbore and provides a path for producing fluids to the surface. Conventionally, the casing is cemented to the wellbore face and is subsequently perforated by detonating shaped explosive charges. When detonated, each shaped charge generates a jet that penetrates through the casing and forms a tunnel into the adjacent formation. Often, a perforating tool has two or more perforating guns, each of which contains shaped charges supported by a charge holder and housed within a carrier. In some systems, the carrier may include regions of reduced wall thicknesses, or “scallops.” The shaped charges are aligned with the carrier such that the jets penetrate through the scallops. Often, adjacent perforating guns are connected using a threaded connection. Due to manufacturing tolerances or other machining issues, the threaded connection, when fully made up, may result in a rotational misalignment between the shaped charges and associated scallops of each perforating gun. This misalignment may cause the jets formed by the shaped charges of each perforating gun to travel in different angular directions.
In aspects, the present disclosure addresses the need to rotationally align two or more perforating guns. In further aspects, the present disclosure addresses the need to rotationally align two or more portions of a downhole tool.
In aspects, the present disclosure provides a system for aligning scallops in a perforating tool.
In aspects, the present disclosure provides a method for aligning scallops in a perforating tool.
The above-recited examples of features of the disclosure have been summarized rather broadly in order that the detailed description thereof that follows may be better understood, and in order that the contributions to the art may be appreciated. There are, of course, additional features of the disclosure that will be described hereinafter and which will form the subject of the claims appended hereto.
For detailed understanding of the present disclosure, references should be made to the following detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals and wherein:
Aspects of the present disclosure relate to rotationally aligning two or more portions of a downhole tool. Such rotational alignment may be desirable in order to have devices of adjacent portions have a specified relative angular orientation. For example, the devices may be required to have angular alignment; i.e., all point in the same angular direction. In some situations, it may be desirable to have a specified relative angular offset; e.g., two or more sets of adjacent devices may have a relative angular offset of thirty degrees, forty-five degrees, sixty degrees, ninety degrees, one-hundred twenty degrees, one-hundred eighty degrees, etc. Exemplary devices may include sensors, coring tools, anchors, stabilizers, steering tools, and shaped charges. While the description below is directed to perforating tools having shaped charges, it should be understood that the present disclosure is not limited to such devices.
Referring now to
The perforating tool 32 may include a plurality of guns 33a-c, each of which includes detonators (not shown), detonating cords (not shown), and one or more shaped charges 40. When detonated in the wellbore 16, the shaped charges 40 produce perforations 60 through the casing 26, cement (not shown), and the surrounding formation 12. This detonation establishes communication between the formation 12 and wellbore 16 by providing a path for formation fluids and gases to enter the wellbore 16. The process for detonating the shaped charges 70 may be referred to as “firing” the perforating tool 32.
Referring to
When the perforating tool 32 is fired, the thermal energy and shock wave released by the explosive material 54 upon detonation transforms the liner 48 into a molten jet (not shown). The molten jet (not shown) penetrates through the wall 71 of the scallop 70 and eventually tunnels into the surrounding formation to form a perforation.
Referring now to
In embodiments, a threaded connection may be used to interconnect the perforating guns 33a,b. For example, the perforating gun 33a may include internal threads 110 formed on a box end 112 and the perforating gun 33b may include external threads 116 formed on a pin end 118. The internal threads 110 and the external threads 116 are collectively referred to as the “threaded connection.” The threaded connection is susceptible to at least two assembly issues. First, a certain amount of angular misalignment may be present between the planes 90 and 92 after the threaded connection is torqued to the maximum allowed value. Attempting further relative rotation to align the planes 90 and 92 may over-torque and damage the threads 110, 116. Second, the threaded connection may allow the desired alignment between the planes 90 and 92, but there is insufficient locking force to keep the threaded connection made up. Thus, to obtain the desired locking force, additional relative rotation may be required to obtain the desired locking force, which may result in angular misalignment of the planes 90 and 92.
One instance in which angular misalignment is undesirable is if only a specific location 82 in the wellbore is intended to be perforated. This angular misalignment may result in sectors or areas of the formation being unintentionally perforated. Another instance is the presence of one or more objects 84 in the vicinity of the perforation. Illustrative objects 84 include communication lines, hydraulic lines, downhole tooling, etc. Misdirected perforating jets may damage such objects 84.
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The alignment member 120 may be a deformable member that enables the relative rotational position of the box end 112 and the pin end 118 to be varied while still maintaining the locking force required for the box end 112 and the pin end 118 to remain connected to one another during use.
First, as noted above, a certain amount of angular misalignment may be present between the planes 90 and 92 after the threaded connection is torqued to the maximum allowed value. However, by deforming, the alignment member 120 allows additional relative rotation to align the planes 90 and 92 without over-torquing and damaging the threads 110, 116. Thus, the alignment member 120 increases the angular range in which a maximum amount of locking force is present to lock the box end 112 and pin end 118.
Second, as also noted above, the threaded connection may allow the desired alignment between the planes 90 and 92 but insufficient locking force may be present. The alignment member 120 can be dimensioned to contact the box end 122 and the pin end 118 during relative rotation and before alignment of the planes 90 and 92 occurs. The contact deforms the alignment member 120 and introduces a locking force to keep the threaded connection made up before the desired alignment is obtained so that no additional relative rotation is required to obtain the desired locking force.
In embodiments, the thickness and the modulus of elasticity may be selected to provide the alignment member 120 with the desired elastic characteristics. For example, some or all of the alignment member 120 may be formed of copper or materials having a modulus of elasticity similar to copper (e.g., within 20% of the modulus of elasticity of copper). By thickness, it is meant an axial distance such as the distance separating the box nose end 122 and the pin end shoulder 124.
In one embodiment, the thickness of the alignment member 120 is selected such that the alignment member 120 contacts and is squeezed between the box end nose 122 and the pin end shoulder 124 at least one full rotation before the internal threads 110 are fully engaged with the external threads 116. By fully engaged, it is meant that no further rotation is possible without damaging either the internal threads 110 or the external threads 116. Further, the material of the alignment member 120 is selected such that the locking force provided by the alignment member 120 is sufficient to maintain a connection over a specified angular range; e.g., 5 degrees.
The alignment member 120 may have a configuration different from the ring-shape shown. For example, the alignment member 120 may be ring shaped, “C” shaped, have an irregular thicknesses, or be formed of two or more different materials. Generally, any body or structure that provides a desired spring force and elastic behavior to generate the required locking force over a specified angular range may be used.
In one arrangement, the internal threads 110 and the external threads 116 may be machined to obtain a desired pre-alignment between the planes 90 and 92. The desired pre-alignment may occur after a specified amount of torque has been applied to the mating ends of the guns 33a,b to “make up” the threaded connection. By “make up,” it is meant completing the threaded connection such that the guns 33a,b are ready for deployment in the wellbore 16 (
During assembly, the box end 112 and the pin end 118 are made up by relative rotation until the alignment member 120 is compressed between the box end nose 122 and the pin end shoulder 124. To obtain such compression, the alignment member 120 has a thickness selected to contact the pin end 118 and the box end 112 before the pin end 118 and the box end 112 can rotate into the specified angular alignment. Next, additional relative rotation is made until the plane 90 and plane 92 (
Referring to
To “clock” the guns 33a,b, the alignment members 120a,b discussed above may be used. Alignment member 120a is positioned at the threaded connection between nose of the box end 150a and shoulder of pin end 162a and alignment member 120b is positioned at the threaded connection between nose of the box end 150b and shoulder of the pin end 162b. The alignment members 120a,b are constructed and function similarly to the alignment members previously discussed.
Also, markers may be used on the guns 33a,b and the pin sub 160. For example, carrier 34a of the gun 33a may include a marker 170a at or near the box end 150a and carrier 34b of the gun 33b may include a marker 170b at or near the box end 150b. Also, the pin sub 160 may include markers 164a,b at or near the pin ends 162a,b respectively. It should be noted that the markers 164a,b may be one continuous marker in some embodiments. When all of the markers 170a,b and 164a,b are aligned with one another within a specified tolerance, then gun 33a may be considered “clocked” with gun 33b.
In use, the threaded connection between box end 150a and pin end 162a is made up until the marker 170a is aligned with the marker 164a. The alignment member 120a deforms as needed to allow the desired alignment. In like manner, the threaded connection between box end 150b and pin end 162b is made up until the marker 170b is aligned with the marker 164b. The alignment member 120b deforms as needed to allow the desired alignment. In some embodiments, the markers 170a,b and 164a,b are visible before, during, and after assembly. The markers 170a,b and 164a,b be a physical deformation such as a scratch or groove or an applied marker such as paint or dye.
The markers may also be used in embodiments where a pin sub is not used. Referring to
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In one embodiment, the locking member 200 may be configured to allow the tabs 202, 204 to have move axially to and from one another. For example, tabs 202, 204 may each project from opposing faces 211, 213, respectively, of a body 206. A slit 208 partially physically separates the tabs 202, 204, which provides elasticity in the body 206 in the vicinity of tabs 202, 204. Thus, the tabs 202, 204 can flex in an axial direction relative to one other. The axial direction is shown with the arrows labeled 217. The body 206 may be a continuous ring as shown. In variants not shown, the body 206 may be C-shaped, be composed of two or more structures or materials, or have an irregular shape or other geometry.
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It should be appreciated that locking members of the present disclosure are susceptible to numerous variations as discussed below.
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As noted previously, the teachings of the present disclosure are not limited to perforating tools. Referring to
From the above, it should be appreciated that the present disclosure includes in part, an apparatus for perforating a subterranean formation that comprises a first perforating gun having a box end having a nose, a second perforating gun having a pin end having a shoulder; and an alignment assembly. The alignment assembly includes internal threads formed on the box end, external threads formed on the pin end, and an alignment member positioned between the box end nose and the pin end shoulder. The internal threads and the external threads are specified to form an angular alignment between the first perforating gun and the second perforating gun within a first specified angular tolerance. The alignment member has at least one characteristic selected to vary the angular alignment within the first specified angular tolerance without degrading a locking force connecting the first perforating gun to the second perforating gun.
From the above, it should be appreciated that what has been described further includes an apparatus having a first perforating gun having a box end having a nose; a second perforating gun having a box end having a nose; a pin sub having a first pin end with a first shoulder and a second pin end with a second shoulder; and an alignment assembly. The alignment assembly may include internal threads formed on the box ends of the first perforating gun and the second perforating gun, external threads formed on the pin ends of the pin sub, a first alignment member positioned between the first box end nose and the first pin end shoulder, and an second alignment member positioned between the second box end nose and the second pin end shoulder. The internal threads and the external threads may be specified to form an angular alignment between pin sub, the first perforating gun, and the second perforating gun within a first specified angular tolerance. The first and the second alignment member may have at least one characteristic selected to vary the angular alignment within the first specified angular tolerance without degrading a locking force connecting the pin sub to the first perforating gun and to the second perforating gun. Additionally, the first gun may include a first marker, the second gun may include a second marker, and the pin sub may include at least a third marker. The alignment of the first marker, the second marker, and the at least third marker within a specified angular value indicates that the first specified angular tolerance is present.
As used above, the following terms are used interchangeably: “angular mis/alignment” and “rotational mis/alignment;” “gun” and “perforating gun,” and “axial” and “longitudinal.” The term “specified” means that a value is predetermined using known engineering techniques.
The foregoing description is directed to particular embodiments of the present disclosure for the purpose of illustration and explanation. It will be apparent, however, to one skilled in the art that many modifications and changes to the embodiment set forth above are possible without departing from the scope of the disclosure. Thus, it is intended that the following claims be interpreted to embrace all such modifications and changes.
Filing Document | Filing Date | Country | Kind |
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PCT/US2021/030490 | 5/3/2021 | WO |
Number | Date | Country | |
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63019065 | May 2020 | US | |
63055182 | Jul 2020 | US | |
63182575 | Apr 2021 | US |