Patent Grant
9284824
The invention relates, in general, to a method and apparatus for perforating wells, and more particularly to an expendable tubing conveyed perforator assembly.
Without limiting the scope of the present invention, its background will be described with reference to perforating a hydrocarbon bearing subterranean formation with a shaped-charge perforating apparatus.
Two primary methods are extensively used to perform tubing-conveyed perforation (TCP) operations in the oil and gas recovery industry. A typical TCP assembly comprises an inner metallic tubular on which are mounted a plurality of shaped-charge explosives, positioned within an outer metallic tubular which acts as a housing, protective covering, fluid isolation, and tension and radial load bearing structure. The assembly includes detonation cords, etc., as are known in the art. The shaped charges, when fired, perforate the outer tubular, the casing (if present), and the formation. The outer and inner tubulars are often severely damaged, fragmented and misshapen during the process. The outer tubular, now perforated, often has projections extending at the circumferences of the perforations.
In one of the primary methods currently in use, any remaining portion of the TCP assembly, after firing, is pulled out of the casing and can be reloaded with charges and reused, if intact. However, this method has several disadvantages since in many drilling situations the inner tubular on which the shaped charges are mounted is damaged to such a degree that it cannot be removed from the hole without destroying the well.
The other method used in the industry is to utilize expendable TCP perforators to fire the charges. Following firing, the expendable perforating system is dropped to the bottom of the drilled hole that extends below the targeted formation, that is, into the rathole. However, drilling the rathole portion of the well requires additional drilling to depths as much as 2,000 feet beyond the target area so that the expended perforator can be accommodated. This extra drilling results in considerable additional time and drilling costs. In addition, the conventional metal tubing used for the TCP assembly generally fragments into large pieces of debris upon firing of the charges. These large pieces of metal debris often cause problems in fluid extraction, such as jamming of equipment, preventing tube removal, inhibiting fluid flow, contaminating the fluid, or clogging pumps or tubing used to extract the fluid.
Thus an expendable TCP assembly is needed which reduces these problems. The purpose of this invention is to develop a tubing conveyed perforator that does not require substantial additional rathole drilling and reduces the potential to clog oil extraction equipment with debris.
Methods and apparatus are presented for a “disappearing” perforator gun assembly. In a preferred method of perforating a well casing, inserted into the well casing is a tubing conveyed perforator having an outer tubular made from a metallic glass alloy having high strength and low impact resistance. An inner structure is positioned within the outer tubular and holds one or more explosive charges. Upon detonating the explosive charges, the outer tubular is fragmented. The inner structure is preferably also substantially destroyed upon detonation of the one or more explosive charges. For example, the inner structure can be made from a combustible material, corrodible, dissolvable, etc., material. Exemplary metallic glass alloys are Zr41.25 Ti13.75 Ni10 Cu12.5 Be22.5, Mg65 C25 Tb10, and Fe59 Cr6 Mo14 C15 B6. A disintegration-enhancing material is optionally positioned between the outer tubular and the inner structure.
Additional embodiments are presented having corrodible, dissolvable, reactive, meltable, etc., outer tubulars and inner structures.
For a more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts and in which:
It should be understood by those skilled in the art that the use of directional terms such as above, below, upper, lower, upward, downward and the like are used in relation to the illustrative embodiments as they are depicted in the figures, the upward direction being toward the top of the corresponding figure and the downward direction being toward the bottom of the corresponding figure. Where this is not the case and a term is being used to indicate a required orientation, the Specification will state or make such clear. Upstream and downstream are used to indicate location or direction in relation to the surface, where upstream indicates relative position or movement towards the surface along the wellbore and downstream indicates relative position or movement further away from the surface along the wellbore.
While the making and using of various embodiments of the present invention are discussed in detail below, a practitioner of the art will appreciate that the present invention provides applicable inventive concepts which can be embodied in a variety of specific contexts. The specific embodiments discussed herein are illustrative of specific ways to make and use the invention and do not limit the scope of the present invention. The description is provided with reference to a vertical wellbore; however, the inventions disclosed herein can be used in horizontal, vertical or deviated wellbores.
As described above, the invention is drawn to an expendable tubing conveyed perforator comprising an outer tubular made from a metallic glass alloy having high strength and low impact resistance and an inner structure made from a combustible material, the inner structure supporting one or more explosive charges. The present invention overcomes problems with prior art TCPs in that substantially all of the outer tubular is fragmented upon detonation, and the inner structure is combustibly consumed upon detonation. Thus, the expendable TCP of the present invention does not require that an extended rathole be prepared, nor depressurization of the well system for perforator removal. In addition, due to the highly frangible nature of the materials used to make the outer tubular of the TCP of the present invention, the pieces produced after detonation of the expendable TCP are less likely to inhibit fluid flow or clog the extraction equipment.
The thickness of the outer tubular 12 is preferably thin enough such that the tube fragments into small pieces upon detonation, yet thick enough to provide structural integrity and protection to the inner structure. Preferably, the outer tubular possesses sufficient axial tensile strength necessary to support the vertical combined weight of the system when situated in the well hole. The outer tubular preferably also possesses sufficient axial compression strength required to move the TCP unit around bends or maintain a non-vertical position. It will be appreciated that the thickness of the outer tubular will vary depending on parameters of the metallic glass alloy, the selected tool design, the shaped charges, the specific application and result required, etc. These parameters are well-known to those skilled in the art.
The outer tubular portion 12 of the present invention should also be able to withstand the environmental conditions encountered in a well hole at 1,000-40,000 feet. Generally, these conditions include temperatures in the range of about 200 degrees to about 350 degrees Fahrenheit, pressures in the range of about 6,000 to 20,000 psi, and exposure to corrosive and/or noxious chemicals such as hydrogen sulfide, calcium hydroxide, and carbon dioxide.
The frangible nature of the metallic glass alloys used to construct the outer tubular results in high fragmentation of the outer tubular upon detonation of the explosive charges. Preferably, the outer tubular is fragmented into pieces less than about 4 inches, more preferably less than about 1 inch, and most preferably less than about 0.1 inches. The outer tubular can be made of a single or a combination of metallic glass alloys. The outer tubular may not be entirely made of metallic glass alloy.
According to the invention, the inner structure 14 is positioned within the outer tubular and preferably parallel to the longitudinal axis L of the outer tubular 12 as shown in
The inner structure 14 of the invention is made from a combustible structural material such as nitrocellulose, wood cellulose, cardboard, fiberboard, thermoplastic, thermoset resin, thin gauge metals, structural foam, and the like. The materials used to manufacture the inner structure 14 are combustible upon detonation of the explosive charges, and following detonation, the material that makes up the inner structure is substantially combustibly consumed, leaving only ash and minor residue.
An optional tubular layer of disintegration-enhancing material 13 may be positioned within the outer tubular 12 and parallel to the longitudinal axis L of the outer tubular 12 as shown in
Unlike the inner structure 14, the optional disintegration-enhancing material 13 is not required to possess extensive structural capability. Upon combustion, the optional disintegration-enhancing material 13 provides additional energy to aid in disintegrating frangible outer tubular 12 into small pieces.
The expendable tubing conveyed perforator 10 of the invention may be combined in sections to produce a longer perforator unit 25 as shown in
In use, the expendable tubing conveyed perforator is lowered into the well casing to the desired depth and detonated using conventional procedures. The frangible nature of the metallic glass alloys of the outer tubular cause it to fragment upon detonation into a multitude of small pieces, preferably less than about 3 inches in size. Concomitantly, the combustible material that makes up the inner structure is substantially combustibly consumed leaving only minor amounts of ash and residue. The small fragmented pieces of the outer tubular either fall to the bottom of the well and, due to their small size, compact into a small volume in the “rathole” portion of the well, or pumped out of the well at a later time. Thus, shorter ratholes are required when utilizing the expendable TCP of the invention as compared with TCPs of the prior art. In addition, the small pieces of fragmented outer tubular and minor residue generated from combustion of the inner structure substantially reduce the chance of clogging the well or oil extracting equipment. Thus, the present invention, and method of use, eliminates post-fire perforator gun removal by extraction or discarding into a rathole.
The design of the gun system is basically the same as the one disclosed in U.S. Pat. No. 5,960,894, to Lilly, filed Mar. 18, 1998, with a significant difference being the material used to construct the outer hollow carrier.
The outer tubular 12 may be made by a conventional metallic glass alloy manufacturing process. The thickness of the outer tubular 12 is preferably thin enough such that the tubular fragments into small pieces upon detonation, yet thick enough to provide structural integrity and protection to the inner structure. Metallic glasses, as detailed below, can be much stronger than conventional alloys, such as steel. This characteristic is beneficial to the design of the system because the outer tubular can be made to have a thinner wall than a conventional steel carrier while still guaranteeing the structural integrity of the system. At the same time, a thinner outer tubular wall should shatter more easily and into smaller pieces. Preferably, the outer tubular possesses sufficient axial tensile strength necessary to support the vertical combined weight of the system when situated in the well hole. The outer tubular preferably also possesses sufficient axial compression strength required to move the TCP unit around bends or maintain a non-vertical position. The outer tubular portion 12 should also be able to withstand the high-pressure and high-temperature environmental conditions encountered in a well and exposure to corrosive and/or noxious chemicals such as hydrogen sulfide, calcium hydroxide, and carbon dioxide.
The optional tubular layer of disintegration-enhancing material 13 may be positioned between the outer tubular 12 and the inner structure 14. Unlike the inner structure 14, the disintegration-enhancing material 13 is not required to possess extensive structural capability. Upon combustion, the optional disintegration-enhancing material 13 provides additional energy to aid in disintegrating frangible outer tubular 12 into small pieces. This material 13 will also be consumed by combustion upon detonation leaving only ash and minor residue.
As making large sized items can be more difficult with metallic glass alloys, another embodiment of the TCP 30, an example of which is seen at
A connector assembly 38 can be used to connect a stack of sections 32 together. For example,
Metallic glass alloys (or amorphous metal) are metallic material with a disordered atomic-scale structure. In contrast to most metals, which are crystalline and therefore have a highly ordered arrangement of atoms, metallic glass alloys are non-crystalline. There are several ways to produce metallic glass alloys, which include extremely rapid cooling, physical vapor deposition, solid-state reaction, ion irradiation, melt spinning, and mechanical alloying. These alloys can be manufactured from one or multiple metals and chemical elements such as iron, copper, palladium, lead, antimony, lanthanum, magnesium, zirconium, palladium, iron, copper, and titanium.
Metallic glass alloys have a variety of potentially useful properties. In particular, they tend to be stronger than crystalline alloys of similar chemical composition. The strength of a crystalline metal is limited by the presence of defects in the crystalline structure called dislocations. A metallic glass alloy has no crystalline structure and no dislocations, and so its strength can approach the theoretical limit associated with the strength of its atomic bonds. One modern metallic glass alloys, known as Vitreloy, has a tensile strength that is almost twice that of high-grade titanium. On the other hand, metallic glasses are not ductile and tend to fail suddenly when loaded in tension.
The table below presents a comparison of the mechanical properties of some metallic glasses, along with a few conventional alloys for comparison:
We can see from the table that metallic glasses can in fact be quite strong, For instance, iron-based glass in the table (Fe59Cr6Mo14C15B6) is more than twice as strong as a high-strength steel (550 ksi vs. 190 ksi), while its plastic elongation (a measure of ductility) is three times smaller (about 2% compared to 6%), which means it is substantially more brittle.
The invention differs from earlier attempts to solve the same problem because it uses metallic glass alloys for the gun carrier. Previous attempts have been made to solve the same problem using materials such as carbon fibers, glass fibers, or combinations thereof. U.S. Pat. No. 5,960,894, to Lilly, discloses the use of commercially available polyacrylonitrile (PAN) or pitch-based carbon fibers. It also describes the use E- or S-glass fibers. However, those materials do not sufficiently withstand the high-pressure and high-temperature environmental conditions typically encountered in a well and do not tend to shatter into pieces small enough to accomplish the objective of the design.
Additional embodiments of potential expendable TCPs are described below. These apparatus and methods of use differ from the description above regarding use of metallic glass alloy materials.
Following are descriptions of several apparatus and methods for providing a disappearing perforating gun assembly. The term “dematerialize” is used herein to collectively refer to the various processes which result in the “disappearance” of the perforating assembly or portions thereof; the term is inclusive, but not limited to, dissolving, melting, chemically reacting, fragmenting into small enough pieces to meet the purposes of the invention, decomposing, combusting, and corroding.
First described are embodiments directed to decomposing or corroding the outer tubular.
In one embodiment, as seen in
With continued reference to
Following are methods and apparatus for a “disappearing” gun with dissolving or melting components.
The following are embodiments to fragment the gun carrier outer tubular.
In another preferred embodiment, the gun carrier is made from a ceramic material which provides mechanical properties to survive deployment into the well but easily breaks-up or shatters during the explosive detonation. The ceramic material would have brittle characteristics that cause shattering during a perforation event.
The following described methods for collapsing or reducing the housing of the perforating gun assembly.
In an additional embodiment, a strip-type gun design is used in conjunction with a retrievable carrier. A wireline type perforating system is employed having capsule charges loaded onto a deployment strip. Since the strip is not durable enough for TCP deployment techniques, a carrier or deployment housing covers the loaded strip during the trip in the well. After positioning at the correct well depth, the strip gun is released and the carrier is retrieved back to the surface. The resulting debris after detonation from the strip gun is substantially less than the traditional TCP carrier equipment remaining after detonation.
Further disclosure regarding strip type guns can be found at U.S. Pat. No. 5,662,178, to Shirley, filed on Mar. 29, 1996, which is hereby incorporated herein for all purposes.
The methods and apparatus discussed with respect to the outer tubular may also or alternately be used in regard to the inner structure.
An additional method would use a delay-effect to create an aftershock or sustained shock after the perforation event. The delayed initiation detonates a second train of explosives with the sole purpose of creating specific forces to break-up the perforator assembly and/or its constituent parts.
An additional method is to make the outer tubular of cast iron which has relatively little elongation. The lower elongation should result in break-up into smaller pieces. Further, additional det cord or a later-fired det cord (after the perforating event) can be used. The delayed det cord initiation would enhance destruction, since by that time the carrier body is filled with fluid. The secondary explosion would consequently create great pressure on the carrier.
A method of perforating a well casing, comprising the steps of: inserting into the well casing a tubing conveyed perforator having an outer tubular made from a metallic glass alloy having high strength and low impact resistance, and an inner structure positioned within the outer tubular and holding one or more explosive charges; detonating the one or more explosive charges; and fragmenting the outer tubular upon detonation of the one or more explosive charges. The method can further include steps: substantially destroying the inner structure upon detonation of the one or more explosive charges; wherein the inner structure is made from a combustible material, and further comprising the step of combustibly destroying the inner structure; wherein the inner structure is made from a corrosive material, and further comprising the step of corroding the inner structure; wherein the inner structure is made from a dissolvable material, and further comprising the step of dissolving the inner structure; and wherein the tubing conveyed perforator further comprises a disintegration-enhancing material positioned between the outer tubular and the inner structure. The disintegration-enhancing tube is made from a material selected from the group consisting of nitrocellulose, wood cellulose, cardboard, fiberboard, thermoplastic, thermoset resin, structural foam, and combinations thereof. The disintegration enhancing material can be a solid, liquid, gel, or a plurality of loose particles (such as sand). The metallic glass alloy is selected from the group consisting of Zr41.25 Ti13.75 Ni10 Cu12.5 Be22.5, Mg65 Cu25 Tb10, and Fe59 Cr6 Mo14 C15 B6. A protective coating can be used on the exterior of the outer tubular.
Disclosure regarding methods for actuating firing heads and types of differential firing heads can be found in the following references, which are each incorporated herein by reference for all purposes: U.S. Pat. No. 5,301,755, to George; U.S. Pat. No. 4,917,189, to George; U.S. Pat. No. 5,161,616, to Colla; U.S. Pat. No. 4,566,544 to Bagley; U.S. Pat. No. 4,616,718 to Gambertoglio; and U.S. Pat. No. 5,297,718 to Barrington. Disclosure regarding the use of tubing-conveyed perforators can be found in the following references, which are hereby incorporated herein by reference for all purposes: U.S. Pat. No. 5,960,894, to Lilly, entitled Expendable tubing conveyed perforator; U.S. Pat. No. 6,422,148, to Xu, entitled Impermeable and composite perforating gun assembly; U.S. Pat. No. 5,477,785, to Dieman, Jr., entitled Well pipe perforating gun; U.S. Pat. No. 4,905,759, to Wesson, entitled Collapsible gun assembly; U.S. Pat. No. 4,467,878, to Ibsen, entitled Shaped charge and carrier assembly therefor; and International Patent Publication WO2005/035940A1, to Meddes, entitled Improvements in and relating to perforators.
Further disclosure regarding shaped-charges, perforation assemblies, etc., can be found in the following references which are hereby incorporated in their entirety for all purposes: U.S. Pat. No. 3,589,453 to Venghiattis, U.S. Pat. No. 4,185,702 to Bullard, U.S. Pat. No. 5,449,039 to Hartley, U.S. Pat. No. 6,557,636 to Cernocky, U.S. Pat. No. 6,675,893 to Lund, U.S. Pat. No. 7,195,066 to Sukup, U.S. Pat. No. 7,360,587 to Walker, U.S. Pat. No. 7,753,121 to Whitsitt, and U.S. Pat. No. 7,997,353 to Ochoa; and U.S. Patent Application Publication Nos. 2007/0256826 to Cecarelli, 2010/0300750 to Hales, and 2010/0276136 to Evans. Various arrangements of shaped-charges may be employed.
Presented are several methods. A method of perforating a well casing, comprising the steps of: inserting into the well casing a tubing conveyed perforator having an outer tubular made from a metallic glass alloy having high strength and low impact resistance, and an inner structure positioned within the outer tubular and holding one or more explosive charges; detonating the one or more explosive charges; and fragmenting the outer tubular upon detonation of the one or more explosive charges. The same method can comprise additional steps and details: substantially destroying the inner structure upon detonation of the one or more explosive charges; wherein the inner structure is made from a combustible material, and further comprising the step of combustibly destroying the inner structure; wherein the inner structure is a tubular having a plurality of holes therein for supporting the one or more explosive charges; wherein the inner structure is made from a corrosive material, and further comprising the step of corroding the inner structure; wherein the inner structure is made from a dissolvable material, and further comprising the step of dissolving the inner structure; wherein the tubing conveyed perforator further comprises a disintegration-enhancing material positioned between the outer tubular and the inner structure; wherein the disintegration-enhancing material is chemically reactive with the outer tubular; and/or wherein the outer tubular further comprises a protective coating on its exterior surface.
A further method is presented. A method of perforating a well casing, comprising the steps of: inserting into the well casing a tubing conveyed perforator having an outer tubular member and an inner structure positioned within the outer tubular, the inner structure supporting one or more explosive charges; detonating the one or more explosive charges; and dematerializing the outer tubular upon detonation of the one or more explosive charges. The same method can include additional steps and details: dematerializing further comprises substantially corroding the outer tubular member; wherein the outer tubular member is made of aluminum; wherein the step of corroding further comprises corroding the outer tubular member with wellbore fluids; wherein the step of corroding further comprises the step of pumping a corrosive fluid into the well; further comprising the step of delaying the corroding of the outer tubular member for a selected period; wherein the step of delaying further comprises the step of corroding a protective layer of material exterior to the outer tubular member; wherein the outer tubular member is made of a corrosive material with inclusions of relatively more corrosive material; wherein the step of dematerializing further comprises the step of reacting a material carried interior to the outer tubular member with wellbore fluids; further comprising the step of altering the pH of the wellbore fluid, and further comprising the step of dematerializing the outer tubular member using the pH-altered fluid; wherein the material carried interior to the outer tubular member is a powdered acidic or basic material; wherein the step of dematerializing further comprises substantially corroding the outer tubular member; further comprising dematerializing a delay layer positioned exterior to the outer tubular member; wherein the tubing conveyed perforator further has an interior space defined between the outer tubular member and the inner structure, and wherein the interior space is positioned at least one interior material; wherein the interior material is a sand-salt matrix; further comprising the step of providing structural support to the outer tubular member with the interior material; wherein the outer tubular member is a thin layer of metal; wherein the step of reacting further comprises reacting the material carried interior of the outer tubular member with a material of the outer tubular member; wherein the step of reacting further comprises reacting the material carried interior to the outer tubular member and a material of the outer tubular member in the presence of wellbore fluid or fluid pumped downhole; wherein the step of dematerializing further comprises the step of consuming the outer tubular member or an interior liner in response to detonation of the charges; wherein the outer tubular member or the interior layer is made at least partly of zinc or magnesium; wherein the outer tubular member or the interior layer is made at least partly of propellant; wherein the step of dematerializing further comprises the step of dissolving or melting the outer tubular member; wherein the step of melting further comprises melting the outer tubular member in response to a thermite reaction initiated by the detonation of the charges; wherein the outer tubular member is made of or contains a substance used in the thermite reaction; wherein an interior layer is made of a material used in the thermite reaction; wherein the outer tubular member is made of a plastic material; wherein the step of dematerializing further comprises the step of dissolving at least one material of a mixture of materials forming the outer tubular member; wherein the at least one material dissolves in hydrocarbon fluid; wherein another of the materials of the mixture is a metal; wherein the step of dematerializing further comprises fragmenting the outer tubular member; wherein the outer tubular member is comprised of metallic glass alloy, powdered metal, or ceramic; wherein the outer tubular member is made up of a plurality of layers of material, including at least one layer made of non-bonded material; wherein the outer tubular member has energetic material imbedded therein; and/or wherein interior of the outer tubular member is a mixture of energetic material and inert material.
A further method is presented. A method of perforating a well casing positioned downhole in a well, comprising the steps of: inserting into the well casing a tubing conveyed perforator having an outer tubular member and an inner structure positioned within the outer tubular, the inner structure holding one or more explosive charges, and a support structure without which the outer tubular member would collapse after insertion into the well; detonating the one or more explosive charges; damaging the support structure in response to the detonation; and collapsing the outer tubular in response to damaging the support structure. The method can further include additional steps and details: further comprising damaging a wire frame support structure positioned exterior to the charges; further comprising combusting detonation cord attached to the wire frame support structure; wherein the step of collapsing further includes the step of telescoping adjacent segments of outer tubular members; wherein the step of collapsing further includes the step of elongating or shortening a coiled spring-like member of the support structure; wherein the support structure is an expandable fluid filling the interior of the outer tubular member, wherein the outer tubular member is an expandable membrane capable of sealing the expandable fluid therein; and/or wherein the expandable fluid is a gel at surface temperature and pressure.
Persons of skill in the art will recognize various combinations and orders of the above described steps and details of the methods presented herein.
While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is, therefore, intended that the appended claims encompass any such modifications or embodiments.
This application is continuation of PCT International Application No. PCT/US2012/034599, filed on Apr. 22, 2012, which claims benefit of U.S. Provisional Application Ser. No. 61/477,910, filed on Apr. 21, 2011. Each patent application identified above is herein incorporated in its entirety by reference for all purposes.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4467878 | Ibsen | Aug 1984 | A |
| 5829538 | Wesson et al. | Nov 1998 | A |
| 5960894 | Lilly et al. | Oct 1999 | A |
| 6767419 | Branagan | Jul 2004 | B1 |
| 20020134585 | Walker | Sep 2002 | A1 |
| 20080149345 | Marya et al. | Jun 2008 | A1 |
| 20100300750 | Hales et al. | Dec 2010 | A1 |
| Number | Date | Country |
|---|---|---|
| 9946476 | Sep 1999 | WO |
| Entry |
|---|
| D.J. Branagan, Y.L. Tang, A.V. Sergueeva, A.K. Mukherjee, “Low Temperature Superplasticity in a Nanocomposite Iron Alloy Derived from a Metallic Glass,” Nanotechnology, vol. 14, No. 11, 2003, 12 pages. |
| Written Opinion of PCT Application No. PCT/US2012/034599 dated Dec. 17, 2012: pp. 1-12. |
| Number | Date | Country | |
|---|---|---|---|
| 20140034384 A1 | Feb 2014 | US |
| Number | Date | Country | |
|---|---|---|---|
| 61477910 | Apr 2011 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2012/034599 | Apr 2012 | US |
| Child | 14047355 | US |
