Patent Application
20200224518
The invention relates to the devices for the extraction of minerals from boreholes, namely, to the oil and gas industry and, in particular, perforation of oil and gas wells using shaped-charge perforators designed to make inflow channels of behind-the-casing fluids and gases.
A shaped-charge perforator containing a tube and shaped charges placed in it is known (U.S. Pat. No. 4,747,201).
The disadvantage of this family member is its modest manufacturability and complexity of shaped charge placing in the tube holes due to fixing shaped charges in the tube holes with the use of additional clamps.
A shaped-charge perforator is known comprising a body in the form of a pipe in which charges in individual pressurized cases made of a fragile material (glass, ceramics, ceramized glass) are placed with the use of fastening parts (SU 1607476).
The prior art device includes a number of parts that complicate the design and assembly of the perforator. The parts fastening the charge in the body, and pressurized charge cases made of a fragile material can be classified as the above parts. When the perforator is activated, the above listed parts are destroyed and clog the well. The use of individual pressurized cases significantly increases the overall dimensions of the charge that results in increase in the perforator dimensions. Durability (number of operations) of the perforator is not defined that can result in the body breakage during releasing (accident).
A shaped-charge perforator is known comprising a loading tube in the form of a metal pipe with mounting seats in which pressurized shaped charges that have an individual metal case (individual body), a cord and initiating devices are placed. At that, the size of the mounting seat corresponds to the size of the charge case, and the number of the perforator operations is determined by the ratio of the explosive material quantity and characteristics to the set of strength and dimensional characteristics of the pipe which the perforator loading tube is made of (RU70929, prior art).
The disadvantages of the perforators known in the state of the art are due to the following. Charge cases are made individually, mainly from steel, by turning or pressing and their combination. The production is labor-intensive, there is a lot of waste (in the case of turning method up to 70% of the metal turns into chips). Charges for capsule perforators should be pressurized, therefore they are difficult-to-make. It is necessary to manufacture loading tubes which are necessary for charge placing in hollow-carrier perforators. Generally, tubes are made by the method of metal laser cutting. The technological process is very expensive, there is a lot of waste. For the manufacturing of loading tubes of hollow-carrier perforators, tubes from thick-walled (from 7 to 12 mm) pipes of special-purpose costly steels are used. One requires costly precision equipment and the process of turning the special-purpose threads for the couplings ensuring tightness of perforators during application. The use of metal (generally steel) for manufacturing each individual charge case is due to the process of pressing an explosive cartridge into it—only a metal case can bear the necessary efforts. In turn, due to the big total weight of individual charges, for their fastening and lowering into the well, it is necessary to use high-strength metal pipes with couplings (adapters) for hollow-carrier perforators or special fasteners for capsule perforators. The use of a thick-walled pipe in the prior art perforator constructions is due to the fact that it should bear (preserve shape) the explosion pressure of shaped charges inside it, so that it can be removed after releasing. In case of depressurization, as well as due to defects in manufacture or assembly, conventional hollow-carrier perforators fail or, even worse, break which makes it very difficult and sometimes impossible to remove them from the well. Removing partially failed charges from a discharged hollow-carrier perforator is also a complex and time-consuming operation.
The task at which the claimed invention is oriented is to create a design of shaped-charge perforators increasing the efficiency of their application, allowing to simplify their manufacturing, expand the range of technologies and materials applicable for their manufacturing, decrease the consumption of materials and the number of components for their assembly. The proposed design of perforator meets the modem demands for the productivity and safety of their manufacturing, storage, transportation and application. The design provides for the possibility of separate, partial or fully assembled transportation of parts and factory-assembled perforators to the places of their application. The design of the current perforator allows for assembly and disassembly, both at the places of their manufacturing and at the place of their application, with the possibility of reusing components and their safe disposal. If necessary, the design allows increasing the charge density (number of charges per perforator meter).
The essence of the invention is that the perforator contains a monolithic body with cavities made perpendicular to its longitudinal axis; in each cavity, parts of a shaped (cumulative) charge as well as a protective channel connected through the holes to these cavities are mounted in a tight manner. In the channel, a detonating cord is placed which is ballistically connected through the above holes to the charges wherein each charge cartridge is fixed directly in the body cavity and provided with a liner (shaped charge guide) with an outer cap (lid) installed in it.
Mostly, each shaped charge is provided with a detonation transmission amplifier placed in the body hole made between the shaped charge cavity and the protective channel, closed from the outside with a sealing gasket and notched sleeve.
In particular embodiments of the invention, the cavity with a shaped charge, explosive cartridge and a liner are made with the shape of the mating surfaces of the group: conical, spherical.
In particular embodiments of the invention, the outer cap is in a resting contact upon the body and provided with a flat gasket; in other particular embodiments of the invention, the outer cap of the charge is in a resting contact upon the liner and provided with radial rings of circular section.
In particular embodiments of the invention, the body is made cylindrical or multi-sided from the material of the following groups: metal, ceramics, glass, polymeric materials, and equivalents thereof.
In particular embodiments of the invention, the perforator is made composed of several bodies connected in series with each other.
The drawings do not cover and, moreover, do not limit the total scope of the claims of this technical solution, but they are merely supporting information of the particular embodiments of the perforator.
The perforator contains a monolithic (one-piece) body 6 (for example, all-metal, all-plastic, of ceramic material, etc.) for a group or all charges, with cavities 5 that are made directly in it and oriented perpendicular to its longitudinal axis that are made directly in the material of the body 6 of the perforator of appropriate dimensions. In cavities 5, shaped charges are installed: separately-made (according to the “briquette” technology) interconnected structural parts of the shaped charge: the shaped charge cap 1, the sealing gasket—elastic sealing gasket 2 or sealing gland (rings of circular section) 13, the liner 3, the cartridge 4 of the main explosive (explosive cartridge). In addition, the detonation transmission amplifier 7, the sealing elastic sealing gasket 9, the detonating cord (cable) 10 and the notched sleeve (clip) 11 are placed from the diametrically opposite side in the body 6 (opposite to the cavity 5).
The detonating cord 10 placed in the protective channel 12, made on the outer surface of the body 6 and ballistically connected through the holes 8 with the cartridge 4 in the cavity 5, is connected to each charge. The cartridge 4 of explosive substance of each charge is fastened directly in the cavity 5 of the body 6 and provided with the liner 3 mounted on it with the outer cap 1.
The cavity 5 in the body 6 of the perforator, the explosive cartridge 4 and the liner 3 are made with smoothly curved mating surfaces. In particular embodiments of the invention, the cavity 5 in the perforator body 6, the explosive cartridge 4 and the liner 3 can be equivalently made with conic or spherical mating surfaces.
The claimed design of the perforator is implemented in the presence of the ready-made explosive cartridge 4, i.e. the perforator design is based on the use of the ready-made explosive cartridge 4. The cartridge 4 is made of explosive allowing transportation and installation in ready (pressed) condition.
Mostly, each charge is provided with the detonation transmission amplifier 7, placed in the hole 8 of the body 6 between the cavity 5 with the explosive cartridge 4 and the channel 12 with the detonating cord 10, closed from the outside with the sealing gasket 9 and the notched sleeve 11.
Peripherally, the outer cap 1 board (collar) can be in a resting contact upon the body 6 through the sealing gasket 2, in other cases of embodiment, the outer cap 1 end is in a resting contact upon (directly or through an additional gasket that is not marked) on the liner 3 sealed by radial rings—sealing glands 13.
The perforator can be made composed (assembled) of several series-connected sections (bodies 6) forming the casing.
The body 6 can be made cylindrical or multi-sided from the material from the group: metal, ceramics, glass, polymeric material.
The shaped charge is installed in the perforator body 6 in any sequence from opposite sides of diameter of the perforator body 6. On the shaped charge parts side the installation is performed in the following order. The explosion cartridge 4 is inserted into the cavity 5 of the body 6, a conical (or hemispherical) liner 3 is inserted into the internal cone (or hemisphere) of the cartridge 4, the sealing gasket 2 from a resilient (elastic) material is installed over the guide 3, then these parts are pressed and fixed in the cavity 5 of the perforator body 6 with the cap 1 (
The cap 1 is fixed in the body 6 with a thread or a tight fit (with a preform). If the diameter of the perforator body 6 is significantly greater than the height of the explosive cartridge 4 and liner 3, it is possible to additionally use threaded or V-locking rings (not shown) for fixing in it. In this case, for example, the upper part of the cavity 5 of the body 6 can be made with an internal thread, and the cap 1 with an external thread. The sealing gasket 2 is installed under the stepped board of the cap 1 for sealing. Instead of or in addition to the gasket 2, it is possible to apply self-curing polymeric sealant—gaskets to the mating surfaces of the cap 1.
In other embodiments of the claimed perforator the inner part of the cavity 5 of the body 6 is cylindrical, and explosive cartridge 4 and the guide 3 are fixed in the body with the cap 1 with sealing gaskets 13 (
On the opposite side of the diameter in the through-hole 8 connecting the cavity 5 and the channel 12, the detonation transmission amplifier 7 is placed; on the ledge of the hole connecting the cavity 5 and the channel 12, the sealing gasket 9 is installed which is pressed against the body 6 by the sleeve 11.
The sleeve 10 can be screwed into the thread or pressed into the body 6 of the perforator, preferably, can optionally be sealed with the sealing gasket 9. During the pre-installation the notch of the sleeve 11 is installed coaxially to the channel 12 under the detonating cord 10 in the body 6 of the perforator. The channel 12 in the perforator body 6 has a cross section that is slightly larger than the detonating cord 10, as a result, when the cord 10 is laid there, it provides a recessed position for the protection against the damage from the casing pipe walls during lowering. The channel 12 can be laid on the outer surface of the body 6 both in a spiral and straightforwardly depending on the phasing (angular position) of the charges (parts 1-4) assembled in the perforator body 6.
In this case, the body 6 performs (combines) the functions of the tube, the individual charge case and the general body of the perforator (pipe), thereby eliminating the manufacture of individual charges of the perforator, as such, in special individual cases (i.e. individual metal shells) and/or frames, as well as a number of complex intermediate parts, and the implementation of the relevant assembly operations.
The use of the claimed perforator is made in the usual way for its intended purpose for well perforation.
When charges are initiated using the cord 10, the explosive of the cartridge 4 detonates, generating heat and forming gases under high pressure. The detonation transmission amplifier 7 provides detonation transmission from the detonating cord 10 to the explosive cartridge 4. In the shaped charges, with the detonation of explosives, due to the presence of the guide 3, a directional jet with a high impact concentration is formed, which provides penetration at a considerable depth.
If necessary, the perforator is disassembled in the reverse order, by unscrewing (in a case of a threaded joint) or “prying” the side end (in a case of pressing in) of the cap 1. Parts 2, 3, 4 are extracted manually with a light tapping on the body 6 of the perforator when turning.
As a result of the implementation of the current technical knowledge, the following technical result can be obtained.
1) Reducing the dimensions, mainly the diameter of the perforator body 6 while maintaining the density of charge and weight of the charge cartridge 4. I.e. the charge for a perforator with a diameter of 85-89 mm is placed in the case 6 with a diameter 20 mm less than the usual which allows using more powerful charges in the casing pipes of smaller diameter.
2) Eliminating the need for the following material and labor-intensive processes:
3) The weight of the body 6 and the whole perforator is reduced by about two times (i.e. the weight is halved), compared to a conventional perforator with charges of the explosive cartridge 4 of the same weight, which will significantly reduce both the direct costs of materials and the indirect costs of transportation, loading and unloading. The design allows, if necessary, to increase the density of charges (the number of charges per perforator meter) or reduce the length of the body with the same number of charges. Furthermore, the outer diameter of the perforator of the present invention is smaller than that of related prior art perforators; however, even with its narrower size, the present invention has the same charge density (i.e., the number of charges per meter). This allows for increased efficiency in perforations within wells having a smaller diameter. Wells which were perforated with charge cartridges weighing 23-26 grams, and a perforator according to the present invention having a diameter of up to 70 mm (2⅞″) had equal efficiency as compared with prior art/currently known perforators having a diameter of up to 89 mm (3⅜″, i.e. an additional half-inch) and prior art charges weighing the same (i.e. 23-26 grams). Therefore, the present invention allows for the same sized charge to work equally as well in a perforator having a smaller outer diameter. While prior art does exist for thru-tubing solutions which comprise perforating devices having a smaller outer diameter than the present invention, such prior art (e.g., Castel, U.S. Pat. No. 2,980,017) are devices which are used for a significantly lower power type of detonation. If, in fact, the charge cartridges of the present invention were to somehow fit into the perforators disclosed in such prior art, the entire tubing of the well would be destroyed. The present invention is applicable to downhole methods in areas significantly larger and having a diameter much larger than applications of devices for thru-tubing solutions.
4) For the manufacture of the perforator body 6, it is possible to use a variety of available modern materials, for example, a variety of light metals, alloys, ceramics, glass, polymers, which will drastically reduce its weight. This reduces cost by lowering material consumption by removing the prior art requirement for a thick outer tube and sometimes also a thin inner tube inside the outer tube, both of which house all the parts of the perforator.
5) Hermetically sealed individual cartridges are specifically disclosed as separately existing and fully sealed in solid form. Such types of charge cartridges are purposely designed to address the previous problem of somehow connected charges, wherein if one charge accidentally is employed, neighboring or nearby charges may also go off. The disclosed perforator having individual and hermetically sealed cartridges significantly reduces the probability of such an event occurring, which in turn saves costs relating to unintended explosions and supply chain errors relating thereto.
Since in the claimed perforator design each charge is sealed separately, depressurization (i.e. failure) of one of them will not result in failure of the others, unlike the well-known hollow-carrier perforators. This will reduce accidents and increase operational safety. Due to the independently sealed nature of the cartridges, the false detonation of one charge also does not lead to a failure or a false detonation of the entire system, as would occur in the prior art.
6) For the production of perforators, the technology range can be expanded. In addition to the metalworking technologies used, it is possible to manufacture the body 6 by casting, both under pressure and without, for metal melts, liquid polymers, glass, up to 3D printing from polymers and ceramics. Furthermore, the cartridges and the perforator bodies may be manufactured separately from each other, which further simplifies the manufacturing process, as well as storage and distribution, stabilizes perforator characteristics, such as weight, density, and geometry and thus increases the stability and quality of performance of the constructed perforators. Another benefit over the prior art is that the perforator of the present invention may be assembled significantly faster than those of the prior art, due to its simple and pre-made design lacking many elements which require construction. Prior art perforating devices are also typically assembled at the place of use of the device, whereas the present invention may be assembled at remote locations, if desired. Furthermore, assembly is safer than before because the charge cartridge is pre-manufactured and no live charge material needs to be provided, pressed, or otherwise handled.
7) It is possible to manufacture the perforator body 6 from materials that are destroyed in the process of detonation (perforation) without the formation of large fragments, such as glass or ceramics. This allows for avoiding the need to recover or dispose of the detonated perforator, i.e., lifting the released perforator and disposing of the body of the device. On the other hand, it is also possible to manufacture the perforator body from a solid steel (or other metallic) material, such that the perforator body is reusable at least several times. The density of the material and its single and solid nature allow for a significant shelf-life of about 2 to 100 detonation cycles, for example, 2-10 cycles, 10-50 cycles, and 50-100 cycles. The shelf-life and reusability of the device would depend on the composition of materials used for the body of the perforator as well as the charge density of the cartridges used. Furthermore, the solid metal body type provides for a minimization of the dynamic shockwave distribution effect. Since there are no gaps or voids between cartridges (i.e. the space between cartridges is voidless), the effect of gaps, openings, and other areas which are not solid metal is realized in this dynamic shockwave distribution. At the moment of detonation, at pressures up to 10,000 psi or more, any gaps, voids, etc. which are present inside the perforator body or housing might contain an inner pressure of about atmospheric pressure, since the perforator is necessarily built at the detonation location. One or more of these gaps, voids, etc., during detonation, may responsible for the effect of dynamic shockwave distribution. By providing an entirely solid and voidless perforator body and housing, with no outer tube or outer liner encasing the perforator and no gaps of air or other material within the perforator body, the present invention significantly minimizes the dynamic shockwave distribution during detonation. Moreover, the one-piece and solid structure of the perforator body also ensures that the openings for the charge cartridges, which must also be precisely positioned relative to the perforator body and relative to each other charge cartridge, remain in proper positions. Prior art devices in this field focus on the integration of many parts together within the perforator body or housing, which lead to a high dynamic shockwave distribution and significantly greater probability of device destruction or need for repair after a single detonation.
8) The liner 3 which is placed within the cartridge is located such that it is not pressed between the charge and the body of the perforator. Instead, the liner is inserted between the recess within the cartridge and the charge material. The liner further comprises a continuous structure with a v-shaped bottom end which corresponds to the shape of the inner surface of the charge cartridge. The inner surface of the charge cartridge comprises a conical indention (i.e., a conical void), such that the outer surface of the liner lays flush against the inner surface of the cartridge. The cartridge itself also comprises a pre-formed single and solid material comprising one or more explosive elements. Because the liner is positioned inside the cartridge, the liner is not deformed at detonation and the performance and efficiency of the cartridges is significantly improved because greater power is associated with the detonation, even though the diameter of the perforator is smaller.
Furthermore, by increasing the weight-to-thickness ratio of the liner, its mechanical strength may also be increased.
There is no mechanical impact on the liner during assembly of the perforator of the present invention, since the liner is already positioned within the charge cartridge. This lack of mechanical impact allows for a reduction of weight of required material to synthesize the liner by a factor between 20% and 40%. In terms of metals, such as tungsten, this provides for significant savings when manufacturing materials, such as liners, in bulk.
The description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. It is intended that the scope of the invention be defined by the following claims and their equivalents.
Moreover, the words “example” or “exemplary” are used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the words “example” or “exemplary” is intended to present concepts in a concrete fashion. As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or”. That is, unless specified otherwise, or clear from context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances. In addition, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form.
This invention is implemented using universal equipment, widely used in industry.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016146577 | Nov 2016 | RU | national |
The present patent application is a Continuation-in-Part of U.S. patent application Ser. No. 16/309,331, which is based on PCT Application Ser. No. PCT/RU2017/000805, filed on Oct. 31, 2017, which in turn claims priority to Russian Patent Application Ser. No. RU2016146577, filed Nov. 28, 2016, all of which are incorporated by reference herein in their entireties.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16309331 | Dec 2018 | US |
| Child | 16837479 | US |
