Layered composite drainage gas recovery string

Abstract

The application discloses a kind of layered composite drainage gas recovery pipe column in the oil and gas exploitation technical field, including casing, suspension packer and N outer layered packer are equipped in casing;Production pipe, coaxially arranged with casing, bottom end is connected with the sealing connection of suspension packer positioning connector;Production pipe, coaxially arranged with production pipe, top and positioning connector are connected;Sand control pipe, coaxially arranged between production pipe and casing, and connected with suspension packer and outer layered packer;N inner layered packer is spaced apart and sealed in the connection between production pipe and sand control pipe along axial direction;Electric control sliding sleeve, N electric control sliding sleeve is spaced apart and arranged on production pipe along axial direction.The application uses space segmentation technical principle, not only can control gas well's exploitation horizon, also can use the electric pump unit of downhole to discharge well bottom fluid to wellhead, to reduce wellbore fluid to formation back pressure, increase formation production differential pressure, restore normal production of water production gas well.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction technology, and specifically to a stratified extraction tubing string. Background Technology

[0002] As offshore oilfields progress in block development and production processes become more refined, the boundary of the gas-water transition zone gradually moves toward the wellbore as pressure decreases during the later stages of oilfield development, with the implementation of water injection and other technologies. Water encounter in gas wells is an inevitable reaction, and the accumulation of fluid in gas wells will increase the back pressure on the oil and gas reservoirs, severely limiting gas well productivity. Therefore, the accumulation of fluid in gas wells has become the most significant factor restricting the high-quality development of offshore oilfields.

[0003] Patent document CN110593846A discloses a gas well gas-liquid separation completion string. This string utilizes the property that liquid has a higher specific gravity than gas, and places the liquid inlet below the gas inlet. Combined with the gas-liquid separation function of the deep-sea submersible pump, it realizes the drainage and gas production operation of the gas well. However, this string is only suitable for the production operation of a single oil and gas layer and cannot avoid the impact of liquid accumulation in the gas well on the lower oil and gas layer when producing multiple oil and gas layers.

[0004] Therefore, how to solve the problem of fluid accumulation in gas wells during multi-oil and gas layer development has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a layered composite drainage gas production string to solve the technical problem of gas well fluid accumulation in existing multi-oil and gas layer production.

[0006] The technical solution adopted in this invention is: a layered composite drainage gas production tubing, comprising: A casing, wherein a suspended packer and N external layered packers are provided inside the casing; The production tube is coaxially arranged with the sleeve, and the bottom end of the production tube is connected to a positioning joint that is sealed to the suspension packer. A mining pipe, which is coaxially arranged with a production pipe, and the top end of the mining pipe is connected to a positioning joint; Sand control pipe; the sand control pipe is coaxially arranged between the mining pipe and the casing, and is connected to the suspended packer and the outer layer packer; An inner packer, N inner packers are axially spaced and sealed between the production pipe and the sand control pipe, and the inner cavity of the sand control pipe is divided into N+1 production layers corresponding to the oil and gas layers. An electrically controlled sliding sleeve, N+1 of which are axially spaced on the mining pipe and correspond one-to-one with the mining layer; Where N is an integer greater than or equal to 1.

[0007] Preferably, a filling mechanism is connected between the production pipe and the positioning joint. The filling mechanism includes an upper joint, a sealing sleeve, and an electric pump unit. The upper joint includes an inner pipe and an outer pipe. The top end of the inner pipe is connected to the production pipe, and the bottom end is connected to the electric pump unit. The top end of the outer pipe is sealed to the inner pipe. The outer pipe is placed outside the electric pump unit, and the top end of the sealing sleeve is sealed to the outer pipe, and the bottom end is sealed to the positioning joint, forming a protective cavity.

[0008] Preferably, the protective cavity is equipped with a working condition sensor connected to the electric pump unit and used to acquire mining information.

[0009] Preferably, the production pipe is connected to a hydraulic control sleeve for draining liquid from inside the production pipe, and the hydraulic control sleeve is located above the filling mechanism.

[0010] Preferably, the hydraulically controlled sliding sleeve is a single-cylinder hydraulically controlled sliding sleeve, with an opening pressure greater than or equal to 5000 psi and a flow area greater than 20 cm². 2 .

[0011] Preferably, a centralizer is provided between the hydraulic control sleeve and the filling mechanism, and the centralizer is coaxially and fixedly connected to the production pipe.

[0012] Preferably, the sand control pipe includes a sealing section and a connecting section arranged alternately along the axial direction. The sealing section is radially sealed to the suspended packer, the outer layer packer, and the inner layer packer. The connecting section is located between the oil and gas layer and the production layer.

[0013] Preferably, 1≤N≤4.

[0014] The beneficial effects of this invention are: This invention employs the principle of spatial segmentation technology. First, multiple outer layer packers are spaced axially within the casing, and multiple inner layer packers are spaced axially within the sand control pipe. The separation effect of the inner and outer layer packers on the casing cavity prevents communication between multiple oil and gas layers, thus avoiding mutual interference from the accumulation of fluid in the gas well between oil and gas layers. Then, multiple electrically controlled sliding sleeves are distributed axially at intervals on the production pipe, with each electrically controlled sliding sleeve corresponding to an oil and gas layer. By controlling the opening and closing of the electrically controlled sliding sleeves at the surface, the production layer of the gas well can be controlled, and the fluid accumulated at the bottom of the well can be discharged to the wellhead, thereby reducing the back pressure of the formation caused by the fluid accumulation in the wellbore, increasing the formation production pressure differential, and restoring the normal production of the water-producing gas well. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the layered composite drainage gas extraction tubing of the present invention; Figure 2 This is a schematic diagram of the filling mechanism.

[0016] Explanation of the reference numerals in the figure: 1. Casing; 2. Suspended packer; 3. Outer layer packer; 4. Production pipe; 5. Positioning joint; 6. Production pipe; 7. Sand control pipe; 8. Inner layer packer; 9. Production layer; 10. Electrically controlled sliding sleeve; 11. Filling mechanism; 12. Upper joint; 13. Packer sleeve; 14. Electric pump unit; 15. Inner pipe; 16. Outer pipe; 17. Protective cavity; 18. Operating condition sensor; 19. Hydraulically controlled sliding sleeve; 20. Sealing section; 21. Connecting section; 22. Centralizer; 23. Oil and gas layer; 24. Plug; 25. Power cable; 26. Cable-through packer; 27. Downhole safety valve. Detailed Implementation

[0017] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0018] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0020] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0021] Examples, such as Figure 1 and Figure 2 As shown, a stratified composite drainage gas production string is used for stratified production operations and drainage gas production operations in gas wells; the string includes: The sleeve 1 has a suspended packer 2 and an outer layer packer 3 inside it, and the suspended packer 2 is located above the outer layer packer 3.

[0022] Production pipe 4 is coaxially arranged with sleeve 1, and the bottom end of production pipe 4 is connected to positioning joint 5, which is sealed to the suspension packer 2.

[0023] The mining pipe 6 is coaxially arranged with the production pipe 4, and the top end of the mining pipe 6 is connected to the positioning joint 5, and the bottom end is connected to the plug 24.

[0024] Sand control pipe 7 is coaxially installed between the mining pipe 6 and the casing 1, and the top end of the sand control pipe 7 is sealed to the suspended packer 2. The number of outer layer packers 3 is N, and the N outer layer packers 3 are axially spaced and sealed between the casing 1 and the sand control pipe 7.

[0025] The number of inner packers 8 is N, and the N inner packers 8 are axially spaced and sealed between the production pipe 6 and the sand control pipe 7, so as to divide the inner cavity of the sand control pipe 7 into N+1 production layers 9 corresponding one-to-one with the oil and gas layer 23.

[0026] The number of electrically controlled sliding sleeves 10 is N+1, and the N+1 electrically controlled sliding sleeves 10 are installed axially on the mining pipe 6. The electrically controlled sliding sleeves 10 correspond one-to-one with the mining layer 9. Where N is an integer, 1≤N≤4.

[0027] This invention employs the principle of spatial segmentation technology. First, multiple outer layer packers 3 are spaced axially within the casing 1, and multiple inner layer packers 8 are spaced axially within the sand control pipe 7. The inner layer packers 8 and outer layer packers 3 can separate the inner cavity of the casing 1, preventing communication between multiple oil and gas layers 23 and thus avoiding mutual interference from the accumulation of fluid between the oil and gas layers 23. Then, multiple electrically controlled sliding sleeves 10 are distributed axially on the production pipe 6, with each electrically controlled sliding sleeve 10 corresponding to one of the oil and gas layers 23. By controlling the opening and closing of the electrically controlled sliding sleeves 10 at the surface, the production layer of the gas well can be controlled, and the fluid collected at the bottom of the well can be discharged from the wellhead, thereby reducing the back pressure of the formation caused by the accumulated fluid in the gas well, increasing the formation production pressure differential, and restoring the normal production of the water-producing gas well.

[0028] In one specific embodiment, such as Figure 1 and Figure 2As shown, a filling mechanism 11 is connected between the production pipe 4 and the positioning connector 5. The filling mechanism 11 includes an upper connector 12, a sealing sleeve 13, and an electric pump unit 14. The upper connector 12 includes an inner pipe 15 and an outer pipe 16. The top end of the inner pipe 15 is fixedly connected to the bottom end of the production pipe 4, and the bottom end of the inner pipe 15 is fixedly connected to the electric pump unit 14. The top end of the outer pipe 16 is sealed to the inner pipe 15. The sealing sleeve 13 covers the outside of the electric pump unit 14, and the top end of the sealing sleeve 13 is sealed to the bottom end of the outer pipe 16. The bottom end of the sealing sleeve 13 is sealed to the positioning connector 5 to form a protective cavity 17 outside the electric pump unit 14.

[0029] This configuration is because, in existing technology, the electric pump unit 14, production pipe 4, and production pipe 6 are often connected using a Y-type joint. The produced oil and gas first enter the casing annulus through the perforated pipe on the production pipe 6, and then enters the production pipe 4 via the electric pump unit 14. However, the produced oil and gas contains corrosive gases, which corrode the casing 1, thus affecting the service life of the tubing string.

[0030] In this embodiment, the electric pump unit 14 is connected to the bottom end of the production pipe 4 through the upper connector 12, and a sealing sleeve 13 is provided on the outside of the electric pump unit 14. The two ends of the sealing sleeve 13 are respectively sealed to the upper connector 12 and the positioning connector 5, which can effectively prevent corrosive gases from entering the casing annulus, thereby extending the service life of the tubing.

[0031] Specifically: the inner tube 15 and outer tube 16 of the upper connector 12 are coaxially arranged, and the top end of the inner tube 15 is a coupling, which is connected to the bottom end of the production pipe 4 by a male thread. The bottom end of the inner tube 15 is an oil pipe male thread, and is connected to the upper pump lifting section of the electric pump unit 14. The top of the upper connector 12 is provided with a through hole with internal thread, through which the power cable 25 and the oil ferrule can pass and be sealed by a threaded cap and a rubber gasket. The top and bottom ends of the packer sleeve 13 are provided with female internal threads, and are fixedly connected to the outer tube 16 and the positioning connector 5 respectively. The lower surface of the positioning connector 5 is provided with a sealing cylinder (not shown) with the same inner diameter as the sealing section 20 of the sandproof pipe 7. The sealing cylinder extends axially and is inserted into the suspension packer 2, and the sealing cylinder and the suspension packer 2 are interference fit.

[0032] Preferably, a working condition sensor 18 is provided in the protective cavity 17. The working condition sensor 18 is connected to the electric pump unit 14 and is used to obtain mining information.

[0033] In one specific embodiment, such as Figure 1 As shown, a hydraulic control sleeve 19 is connected to the production pipe 4, and the hydraulic control sleeve 19 is located above the filling mechanism 11.

[0034] This is because: when performing well washing and pressure operation, it is necessary to drain the liquid in the production pipe 4. However, the bottom end of the production pipe 4 is connected to the electric pump unit 14, and the liquid discharge speed is relatively slow, which affects the efficiency of well washing and pressure operation.

[0035] In this embodiment, a hydraulically controlled sliding sleeve 19 is installed on the production pipe 4 located above the filling mechanism 11. When performing well washing and pressure operation, the liquid in the production pipe 4 can be quickly drained by controlling the opening of the hydraulically controlled sliding sleeve 19, which helps to improve the efficiency of well washing and pressure operation.

[0036] Preferably, the hydraulic control sleeve 19 is a single-cylinder hydraulic control sleeve, and the opening pressure of the single-cylinder hydraulic control sleeve is greater than or equal to 5000 psi, and the flow area is greater than 20 cm². 2 .

[0037] More preferably, a stabilizer 22 is provided between the hydraulic control sleeve 19 and the filling mechanism 11, and the stabilizer 22 is coaxially and fixedly connected to the production pipe 4.

[0038] Specifically: The centralizer 22 adopts a cage-type centralizer structure.

[0039] In one specific embodiment, such as Figure 1 As shown, the sand control pipe 7 includes a sealing section 20 and a connecting section 21 arranged alternately along the axial direction. There are multiple sealing sections 20, which are respectively sealed and connected to the suspended packer 2, the outer layer packer 3 and the inner layer packer 8 in the radial direction. The connecting section 21 is located between the oil and gas layer 23 and the production layer 9.

[0040] In one specific embodiment, such as Figure 1 As shown, a cable packer 26 is sealed between the top of the production pipe 4 and the sleeve 1. The cable packer 26 is a 10,000 psi packer with 5 through holes. The vent valve on the cable packer 26 adopts a multi-stage oil scraper ring type large channel hydraulic plunger structure to ensure the venting volume in the later stage.

[0041] A downhole safety valve 27 is installed at the top of production pipe 4, and the downhole safety valve 27 is a 10000psi-rated self-balancing downhole safety valve.

[0042] The construction process of the tubular column of the present invention is as follows: In the early stage, construction procedures such as sand flushing, well cleaning, and pipe scraping are carried out. The tubing string is adjusted according to the oil layer depth, and the sand control pipe 7 is run in. The top of the sand control pipe 7 is equipped with a suspended packer 2, and the top of the oil and gas layer 23 is aligned with the connecting section 21 of the sand control pipe 7. The bottom of the oil and gas layer 23 is aligned with the sealing section 20 of the sand control pipe 7. The bottom of the sealing section 20 is sealed with the casing 1 by an outer layer packer 3. A plug 24 is installed at the bottom of the sand control pipe 7.

[0043] The length of the packer is adjusted according to the formation length, and it is lowered to the predetermined design depth. The sand control pipe 7 is lifted, pressurized, and lowered, and the outer layer packer 3 is set. The pressure is then increased sequentially to 5MPa, 8MPa, 12MPa, and 15MPa, and stabilized for 5 minutes at each level. After each pressure is stabilized, the pressure is slowly released to 0, and then the pressure is increased again to the next pressure level. The pressure is increased to 18MPa, stabilized for 5 minutes, and the suspended packer 2 is set. The pressure is increased to 20MPa and then suddenly dropped to 0, and the release string is retrieved. The length of the inner layer packer 8 is adjusted according to the length of the sand control pipe 7 left in the well. Electrically controlled sliding sleeves 10 are installed on the production pipe 6 above and below the inner layer packer 8 (preferably a water-swellable packer), and multiple electrically controlled sliding sleeves 10 are connected to the power data line. A positioning connector 5 is installed on the part above the length of the sand control pipe 7, and the upper part is connected to the filling mechanism 11. After suspending the packer sleeve 13 to the wellhead, install the plug 24, electrically controlled sliding sleeve 10, inner layer packer 8, electrically controlled sliding sleeve 10, working condition sensor 18, and electric pump unit 14 in sequence according to length. Then connect it to the upper connector 12. Finally, pass the power cable 25, oil tubing, and data cable through the through hole. After installing the upper connector 12, install the completion string. Connect the cables of the intelligent electrically controlled sliding sleeve 10, working condition sensor 18, and electric pump unit 14 through the cable packer 26. Connect the downhole safety valve 27, install the Christmas tree, and pressurize and set the cable packer 26. Adjust the electrically controlled sliding sleeve 10 on the surface according to the gas production situation, and adjust the production parameters according to the data of the working condition sensor 18. Start the electric pump unit 14 to discharge the wellbore liquid to extend the gas production time.

[0044] Compared with the prior art, this application has at least the following beneficial technical effects: This invention allows for surface control of the extraction layer and the use of a submersible pump unit (EDP) to discharge accumulated fluid from the wellbore, thereby reducing the back pressure of the formation caused by the accumulated fluid in the wellbore, increasing the formation production pressure differential, and restoring normal production of the water-producing gas well. This increases the gas well's production time and generates higher economic benefits.

[0045] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A layered composite drainage gas production tubing, characterized in that, include: The sleeve (1) is provided with a hanging packer (2) and N outer layer packers (3). Production pipe (4), the production pipe (4) is coaxially arranged with the sleeve (1), and the bottom end of the production pipe (4) is connected to a positioning joint (5) that is sealed to the suspension packer (2). The mining pipe (6) is coaxially arranged with the production pipe (4), and the top end of the mining pipe (6) is connected to the positioning joint (5); Sand control pipe (7), which is coaxially arranged between the mining pipe (6) and the casing (1) and connected to the suspended packer (2) and the outer layer packer (3); The inner packer (8) is N packers (8) that are axially spaced and sealed between the production pipe (6) and the sand control pipe (7), and divide the inner cavity of the sand control pipe (7) into N+1 production layers (9) corresponding to the oil and gas layer (23). Electrically controlled sliding sleeves (10), N+1 of the electrically controlled sliding sleeves (10) are axially spaced on the mining pipe (6) and correspond one-to-one with the mining layer (9); A filling mechanism (11) is connected between the production pipe (4) and the positioning connector (5). The filling mechanism (11) includes an upper connector (12), a sealing sleeve (13), and an electric pump unit (14). The upper connector (12) includes an inner pipe (15) and an outer pipe (16). The top end of the inner pipe (15) is connected to the production pipe (4), and the bottom end is connected to the electric pump unit (14). The top end of the outer pipe (16) is sealed to the inner pipe (15). The outer pipe (16) covers the outside of the electric pump unit (14), and the top end of the sealing sleeve (13) is sealed to the outer pipe (16), and the bottom end is sealed to the positioning connector (5), forming a protective cavity (17). Where N is an integer greater than or equal to 1.

2. The layered composite drainage gas extraction tubing string according to claim 1, characterized in that, The protective cavity (17) is equipped with a working condition sensor (18) that is connected to the electric pump unit (14) and used to obtain mining information.

3. The layered composite drainage gas extraction tubing string according to claim 1, characterized in that, The production pipe (4) is connected to a liquid control sleeve (19) for draining the liquid inside the production pipe (4), and the liquid control sleeve (19) is located above the filling mechanism (11).

4. The layered composite drainage gas extraction tubing string according to claim 3, characterized in that, The hydraulically controlled sliding sleeve (19) is a single-cylinder hydraulically controlled sliding sleeve with an opening pressure greater than or equal to 5000 psi and a flow area greater than 20 cm². 2 .

5. The layered composite drainage gas extraction tubing string according to claim 3, characterized in that, A stabilizer (22) is provided between the hydraulic control sleeve (19) and the filling mechanism (11), and the stabilizer (22) is coaxially and fixedly connected to the production pipe (4).

6. The layered composite drainage gas extraction tubing string according to claim 1, characterized in that, The sand control pipe (7) includes a sealing section (20) and a connecting section (21) arranged alternately along the axial direction. The sealing section (20) is radially sealed to the suspended packer (2), the outer layer packer (3) and the inner layer packer (8). The connecting section (21) is located between the oil and gas layer (23) and the production layer (9).

7. The layered composite drainage gas extraction tubing string according to claim 1, characterized in that, 1≤N≤4。

Images