Dual packer zonal rework test string and zonal testing method

Abstract

The present application relates to a kind of double-sealing layered reconstruction test pipe column and its layered test method, test pipe column includes sequentially arranged first pipe column compensator, ball pressurized operation cycle valve, anchoring sealing release device, steel wire plug tool, first hydraulic anchor, first hydraulic recoverable packer, ball pressurized operation fracturing sliding sleeve, pipe column compensator, second hydraulic anchor, second hydraulic recoverable packer, E type ball seat and E type normally open valve.The present application can realize lower reservoir replacement acid, reconstruct lower reservoir and production, reconstruct upper reservoir and production, if lower reservoir water, can close E type normally open valve and block lower reservoir, produce upper reservoir, if need to block reservoir, can use steel wire plug tool to block lower reservoir, then from anchoring release device release, realize temporary blocking lower reservoir, test is carried out in upper return.

Description

Technical Field

[0001] This invention relates to the field of oil and gas extraction technology, and more specifically, to a double-sealed stratification modification test string and its stratification test method. Background Technology

[0002] In the exploration and development of oil and gas fields, for blocks with multiple layers of oil and gas shows, testing operations are often necessary to determine the type of oil and gas resources, providing a reliable basis for formulating development plans. Currently, the most common testing method is layer-by-layer back-to-back testing, but this method requires a long construction period and high costs. Furthermore, if an oil and gas reservoir is discovered during the testing process, the instability of temporary plugging can bring many unfavorable conditions to subsequent layer testing and oil and gas reservoir exploitation. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a double-sealed layered modification test string and its layered testing method, which can test two layers with a single string, and can realize both layered testing and temporary sealing.

[0004] The technical solution adopted by this invention to solve its technical problem is as follows: Construct a double-sealed layered modification test string, including a first string compensator, a ball-throwing and pressurizing operation circulation valve, an anchoring and sealing release device, a steel wire plugging tool, a first hydraulic anchor, a first hydraulic retrievable packer, a ball-throwing and pressurizing operation fracturing sleeve, a second string compensator, a second hydraulic anchor, a second hydraulic retrievable packer, an E-type setting ball seat, and an E-type normally open valve;

[0005] The upper part of the first tubing compensator is connected to an oil pipe, which is used to adjust the change in tubing length caused by temperature effects and pressure expansion.

[0006] The ball-dropping and pressurizing operation circulation valve is used to open the circulation channel for circulation well control before the tubing string is pulled out in the later stage;

[0007] The anchoring and sealing release device is used to release the lower tool and return to the upper reservoir for operations.

[0008] The steel wire plugging tool is used to temporarily plug the lower reservoir and then return it to the upper reservoir;

[0009] The first hydraulic anchor is used to anchor the tubing string when the pressure inside the tubing is greater than the pressure inside the casing, preventing the first hydraulic retrievable packer from being released.

[0010] The first hydraulically retrievable packer is used to separate the upper oil and gas layer;

[0011] The ball-throwing and pressurizing operation fracturing sleeve is used to open the fracturing channel for modifying the upper reservoir through ball-throwing and pressurizing.

[0012] The second tubing compensator is used to adjust the change in tubing length caused by temperature effects and pressure bulging, thereby improving the stress on the tubing.

[0013] The second hydraulic anchor is used to anchor the tubing string when the pressure inside the tubing is greater than the pressure inside the casing, preventing the second hydraulic retrievable packer from being released.

[0014] The second hydraulically retrievable packer is used to separate the lower oil and gas layer.

[0015] In the above scheme, a round-head blind plug is provided below the E-type normally open valve.

[0016] In the above scheme, the E-type setting ball seat is used to set the packer. After the packer is set, the ball is knocked down, and the ball seat does not fall into the well, thus achieving a large diameter.

[0017] In the above scheme, the E-type normally open valve is used to provide a channel to replace the mud in the wellbore with working fluid, or to replace the lower reservoir with acid. Later, a ball can be dropped to close and seal the lower reservoir.

[0018] This invention also provides a layered testing method for the aforementioned double-sealed layered modification test string, comprising the following steps:

[0019] (1) Drilling: Lower the double-sealed stratified modification test string into the well;

[0020] (2) Replace the wellhead, replace the fluid, and set the packer: The tubing string is lowered to the predetermined position, the tubing hanger is set, the blowout preventer is replaced with the production tree and the pressure test is qualified, the mud in the wellbore is replaced with working fluid, the fluid replacement is completed, and a soluble ball matching the E-type setting ball seat is put in through the tubing, the first hydraulic retrievable packer and the second hydraulic retrievable packer are set by pressure testing, the packer is tested and qualified by annular pressure testing, the ball is knocked off, the ball seat does not fall into the well, and the full-bore passage is realized;

[0021] (3) Acid fracturing and blowout testing: After the lower reservoir is fracturing according to the reservoir fracturing plan, blowout testing is carried out and relevant fluid properties and data are recorded.

[0022] (4) Blocking the lower reservoir and opening the upper reservoir channel: After the test, a ball matching the E-type normally open valve is inserted through the tubing, and the E-type normally open valve is closed by pressure to achieve the blocking of the lower production layer; a ball matching the fracturing sleeve is inserted through the tubing, and the ball-dropping and pressure-operating fracturing sleeve is opened by pressure to connect the upper reservoir and form a stimulation channel.

[0023] (5) Acid fracturing and blowout testing: After the upper reservoir is fracturing according to the reservoir fracturing plan, blowout testing is carried out and relevant fluid properties and data are recorded.

[0024] (6) After the test, the ball-dropping and pressurizing operation circulation valve is opened in the tubing to circulate and kill the well until the inlet and outlet fluid properties are consistent and there are no impurities;

[0025] (7) If there is production in the lower reservoir, after killing the well and observing that the well is stable, a wireline plugging tool is lowered to plug the lower producing layer. After the seal is verified, the wireline plugging tool is pulled out, the wellhead is replaced, the tubing string is lifted and rotated forward and released from the anchor seal, the upper test tubing string is pulled out, and the test is performed back up. If there is no production in the lower reservoir, after killing the well and observing that the well is stable, the test tubing string is unsealed, the bridge plug is lowered to plug the lower reservoir, and the test is performed back up.

[0026] The double-sealed, layered modification test string and its layered testing method of the present invention have the following beneficial effects:

[0027] 1. The test string of this invention is equipped with a string compensator to compensate for string shortening caused by temperature effects and pressure bulging, improving the stress on the string; it is equipped with an E-type normally open valve, which can replace the mud in the wellbore with the test working fluid before the hydraulically retrievable packer is set, and closes after the test to seal the lower reservoir; it is equipped with an E-type setting ball seat, which, after the packer is set, is dislodged by tubing pressure operation, preventing the ball seat from falling into the well and achieving full-bore tubing; it is equipped with a ball drop and pressurization operation for fracturing. The system includes a sliding sleeve, which is opened by dropping a ball to enable upper production layer stimulation and testing; a wireline plugging tool is provided to seal the lower production layer after testing; a mechanical release device is provided to release the lower testing tool after sealing the lower reservoir, allowing for return testing to the upper layer; it also allows for subsequent tubing re-insertion to unseal the lower plugging tubing and enable oil and gas extraction; and a ball-dropping pressure operation circulation valve is provided to replace the testing working fluid in the wellbore with kill mud by dropping a ball to open the fluid replacement valve before retrieving the upper release tubing or unsealing the packer, ensuring well control safety.

[0028] 2. This invention can achieve acid replacement in the lower reservoir, modification of the lower reservoir for production, modification of the upper reservoir for production. If water is produced in the lower reservoir, the E-type normally open valve can be closed to block the lower reservoir and the upper reservoir can be produced. If it is necessary to block the reservoir, a steel wire plugging tool can be used to block the lower reservoir and then released from the anchor release device to temporarily block the lower reservoir, and then return to the upper reservoir for testing. Attached Figure Description

[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0030] Figure 1 This is a schematic diagram of the structure of the test column for the double-sealed layered modification of this invention. Detailed Implementation

[0031] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0032] like Figure 1 As shown, the test string for the double-sealed layered modification of the present invention includes, in sequence along the string, a first string compensator 1, a tubing ball-throwing and pressurizing operation circulation valve 2, an anchoring and sealing release device 3, a wire plugging tool 4, a first hydraulic anchor 5, a first hydraulic retrievable packer 6, a tubing pressure operation fracturing sleeve 7, a second string compensator 8, a second hydraulic anchor 9, a second hydraulic retrievable packer 10, an E-type setting ball seat 11, an E-type normally open valve 12, and a round-head blind plug 13.

[0033] The upper part of the first tubing compensator 1 is connected to the oil pipe and is used to adjust the change in tubing length caused by temperature effect and pressure expansion, improve the stress on the tubing, and enhance the safety of the test tubing.

[0034] The first tubing compensator 1 is connected to the ball-dropping and pressurizing operation circulation valve 2. The ball-dropping and pressurizing operation circulation valve 2 is used to open the circulation channel for circulation and well control before the tubing is pulled out, in order to ensure the well control safety of the tripping operation.

[0035] The ball-throwing and pressurizing operation circulation valve 2 is connected to the anchoring and sealing release device 3. The anchoring and sealing release device 3 is used to release the lower tool and return to the upper reservoir operation.

[0036] Anchoring sealing release device 3 is connected to wire rope plugging tool 4. Wire rope plugging tool 4 is used to temporarily plug the lower reservoir and return it to the upper reservoir.

[0037] The wire plugging tool 4 is connected to the first hydraulic anchor 5. The first hydraulic anchor 5 is used to anchor the tubing string when the pressure inside the tubing is greater than the pressure inside the casing to prevent the hydraulic retrievable packer from being released.

[0038] The first hydraulic anchor 5 is connected to the first hydraulic retrievable packer 6, which is used to effectively separate the upper oil and gas layer and protect the upper casing.

[0039] The first hydraulic retrievable packer 6 is connected to the ball-dropping and pressurizing operation fracturing sleeve 7, which is used to open the fracturing channel for modifying the upper reservoir by ball-dropping and pressurizing.

[0040] The ball-throwing and pressure-pressurizing operation fracturing sleeve 7 is connected to the second tubing compensator 8. The second tubing compensator 8 is used to adjust the change in tubing length caused by temperature effects and pressure expansion, improve the stress on the tubing, and enhance the safety of the test tubing.

[0041] The second tubing compensator 8 is connected to the second hydraulic anchor 9. The second hydraulic anchor 9 is used to anchor the tubing when the pressure inside the tubing is greater than the pressure inside the casing, preventing the hydraulically retrievable packer from being released.

[0042] The second hydraulic anchor 9 is connected to the second hydraulic retrievable packer 10, which is used to effectively separate the lower oil and gas layer and protect the upper casing.

[0043] The second hydraulic retrievable packer 10 is connected to the E-type setting ball seat 11. The E-type setting ball seat 11 is used to set the packer. After the packer is set, the ball is knocked off, and the ball seat does not fall into the well, thus achieving a large diameter.

[0044] The E-type setting ball seat 11 connects to the E-type normally open valve 12. The E-type normally open valve 12 is used to provide a channel to replace the mud in the wellbore with working fluid, or to replace the lower reservoir with acid. Later, the lower reservoir can be sealed by dropping a ball.

[0045] Furthermore, this invention provides a method for using a double-sealed, layered modification test string, which, according to the above-described string configuration, includes the following steps:

[0046] (1) Drilling: After connecting the tubing in the order of the double-sealing layered modification test tubing, the tubing is lowered into the well;

[0047] (2) Replacing the wellhead, replacing the fluid, and setting the packer: After the tubing string is lowered to the predetermined position, the tubing hanger is set, the blowout preventer is replaced with the Christmas tree and pressure tested and qualified, the working fluid is used to replace the mud in the wellbore. According to the reservoir geological characteristics, after replacing the wellbore mud, a small amount of acid can be replaced to the reservoir area for acid washing, which is convenient for subsequent stimulation construction. After the fluid replacement is completed, a soluble ball matching the E-type setting ball seat is inserted through the tubing, and the hydraulic retrievable packer is pressure-set. After the annular pressure test and verification of the packer is qualified, the ball is knocked off, and the ball seat does not fall into the well, realizing a full-bore channel;

[0048] (3) Acid fracturing and venting for production: After the lower reservoir is fracturing according to the reservoir fracturing plan, a suitable nozzle is used to conduct a venting test and record the relevant fluid properties and data.

[0049] (4) Blocking the lower reservoir and opening the upper reservoir channel: After the test, a ball matching the E-type normally open valve is inserted through the tubing, and the E-type normally open valve is closed by pressure to achieve the blocking of the lower production layer; a ball matching the fracturing sleeve is inserted through the tubing, and the fracturing sleeve is opened by pressure to connect the upper reservoir and form a stimulation channel.

[0050] (5) Acid fracturing and venting for production: After the upper reservoir is fracturing according to the reservoir fracturing plan, a suitable nozzle is used to conduct a venting test and record the relevant fluid properties and data.

[0051] (6) After the test, the ball is dropped into the tubing to pressurize and open the circulation valve. The well is then circulated until the inlet and outlet fluid properties are consistent and there are no impurities.

[0052] (7) If there is production in the lower reservoir, after killing the well and observing that the well is stable, a wireline plugging tool is lowered to plug the lower producing layer. After the seal is verified, the wireline plugging tool is pulled out, the wellhead is replaced, the tubing string is lifted and rotated forward and released from the anchor seal, the upper test tubing string is pulled out, and the test is performed back up. If there is no production in the lower reservoir, after killing the well and observing that the well is stable, the test tubing string is unsealed, the bridge plug is lowered to plug the lower reservoir, and the test is performed back up.

[0053] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A double-sealed, layered modified test string, characterized in that, The system includes, in sequence, a first tubing compensator, a ball-dropping and pressurizing operation circulation valve, an anchoring and sealing release device, a wire-insertion plugging tool, a first hydraulic anchor, a first hydraulically retrievable packer, a ball-dropping and pressurizing operation fracturing sleeve, a second tubing compensator, a second hydraulic anchor, a second hydraulically retrievable packer, an E-type setting ball seat, and an E-type normally open valve. The upper part of the first tubing compensator is connected to an oil pipe, which is used to adjust the change in tubing length caused by temperature effects and pressure expansion. The ball-dropping and pressurizing operation circulation valve is used to open the circulation channel for circulation well control before the tubing string is pulled out in the later stage; The anchoring and sealing release device is used to release the lower tool and return to the upper reservoir for operations. The steel wire plugging tool is used to temporarily plug the lower reservoir and then return it to the upper reservoir; The first hydraulic anchor is used to anchor the tubing string when the pressure inside the tubing is greater than the pressure inside the casing, preventing the first hydraulic retrievable packer from being released. The first hydraulically retrievable packer is used to separate the upper oil and gas layer; The ball-throwing and pressurizing operation fracturing sleeve is used to open the fracturing channel for modifying the upper reservoir through ball-throwing and pressurizing. The second tubing compensator is used to adjust the change in tubing length caused by temperature effects and pressure bulging, thereby improving the stress on the tubing. The second hydraulic anchor is used to anchor the tubing string when the pressure inside the tubing is greater than the pressure inside the casing, preventing the second hydraulic retrievable packer from being released. The second hydraulic retrievable packer is used to separate the lower oil and gas layer; the E-type setting ball seat is used to set the packer. After the packer is set, the ball is knocked off, and the ball seat does not fall into the well, thus achieving a large diameter; the E-type normally open valve is used to provide a channel to replace the mud in the wellbore with working fluid, or to replace the lower reservoir with acid. Later, a ball can be dropped to close and plug the lower reservoir.

2. The double-sealed, layered modified test string according to claim 1, characterized in that, The E-type normally open valve is equipped with a round-head blind plug at its lower part.

3. A layered testing method for the double-sealed layered modification test string as described in claim 1, characterized in that, Includes the following steps: (1) Drilling: Lower the double-sealed stratified modification test string into the well; (2) Replace the wellhead, replace the fluid, and set the packer: The tubing string is lowered to the predetermined position, the tubing hanger is set, the blowout preventer is replaced with the production tree and the pressure test is qualified, the mud in the wellbore is replaced with working fluid, the fluid replacement is completed, and a soluble ball matching the E-type setting ball seat is put in through the tubing, the first hydraulic retrievable packer and the second hydraulic retrievable packer are set by pressure testing, the packer is tested and qualified by annular pressure testing, the ball is knocked off, the ball seat does not fall into the well, and the full-bore passage is realized; (3) Acid fracturing and blowout testing: After the lower reservoir is fracturing according to the reservoir fracturing plan, blowout testing is carried out and relevant fluid properties and data are recorded. (4) Blocking the lower reservoir and opening the upper reservoir channel: After the test, a ball matching the E-type normally open valve is inserted through the tubing, and the E-type normally open valve is closed by pressure to achieve the blocking of the lower production layer; a ball matching the fracturing sleeve is inserted through the tubing, and the ball-dropping and pressure-operating fracturing sleeve is opened by pressure to connect the upper reservoir and form a stimulation channel. (5) Acid fracturing and blowout testing: After the upper reservoir is fracturing according to the reservoir fracturing plan, blowout testing is carried out and relevant fluid properties and data are recorded. (6) After the test, the ball-dropping and pressurizing operation circulation valve is opened in the tubing to circulate and kill the well until the inlet and outlet fluid properties are consistent and there are no impurities; (7) If there is production in the lower reservoir, after killing the well and observing that the well is stable, a wireline plugging tool is lowered to plug the lower producing layer. After the seal is verified, the wireline plugging tool is pulled out, the wellhead is replaced, the tubing string is lifted and rotated forward and released from the anchor seal, the upper test tubing string is pulled out, and the test is performed back up. If there is no production in the lower reservoir, after killing the well and observing that the well is stable, the test tubing string is unsealed and pulled out, a bridge plug is lowered to plug the lower reservoir, and the test is performed back up.

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