Gas well layer checking and hole patching separate layer fracturing and testing integrated pipe column and testing method

Abstract

The invention discloses a gas well layer checking and hole patching separate layer fracturing and testing integrated tubular column and a testing method, and belongs to the technical field of natural gas well old well separate layer fracturing testing. The gas well layer checking and hole patching separate layer fracturing and testing integrated pipe column comprises an oil pipe, and a gas lift sliding sleeve, a first compression type packer, a production sliding sleeve, a second compression type packer, a ball throwing sliding sleeve, an expanding type packer and a constant pressure sliding sleeve are sequentially arranged on the oil pipe from top to bottom; the first compression type packer and the second compression type packer are used for blocking an old layer section; and the expanding type packer is arranged between two adjacent unmodified layer sections.

Description

Technical Field

[0001] The invention belongs to the technical field of layered fracturing testing of old natural gas wells, and in particular relates to a gas well layer checking and hole filling layered fracturing and testing integrated pipe string and a testing method. Background Art

[0002] The tight gas reservoir in a gas field has the characteristics of "low permeability, low pressure and low abundance", and its gas well production pressure drops quickly and the single well production is low. As the gas field production enters the middle and late stages, problems such as "fast decline and difficulty in stabilizing production" continue to emerge. In order to fully tap the potential of old wells and improve the ultimate recovery rate of gas reservoirs, the layer inspection and perforation filling process is carried out in the old gas field to find undeveloped layers or layers with good gas-bearing performance in low-yield wells for perforation and fracturing to increase the single well production and generate economic benefits. Layer inspection and perforation filling is an effective measure to replace the production capacity of gas wells in the middle and late stages of production. Most of the old layers of the layer inspection and perforation filling gas wells have low pressure and still have certain production potential. How to retain the potential of the old layers and effectively exert the production capacity of the new layers is the key goal of the layer inspection and perforation filling operation. For gas wells that retain the old layers, the new and old layers are often produced after fracturing. There are two problems in production: First, due to the pressure difference between the new and old layers in the vertical direction, the "backflow" after the transformation causes the potential of the old layers to be unable to be effectively exerted. Second, after layer inspection and perforation repair, the new and old layers are produced together. The existing fracturing production tubing cannot carry out production capacity testing on the new layer alone, which affects the reasonable production allocation of the gas well.

[0003] For example, the gas well pressure and measurement process string provided by the prior art CN 201650198 U is mainly composed of an upper oil pipe, a sand-proof hydraulic anchor, a K344 type packer, a medium oil pipe, an upper sliding sleeve test switch, a safety joint, an adjustment short circuit, a lower sliding sleeve switch, a JXY521 type packer, a lower oil pipe and a guide shoe head, which are connected by threads from top to bottom in sequence, and the layered test is completed by using a downhole tool under wire operation. The multifunctional layered testing string for sulfur-containing oil and gas wells provided by CN 114526051 A comprises an oil pipe; a first packer arranged on the oil pipe, the first packer is used to seal the reformed layer section below it; at least one second packer arranged on the oil pipe, the second packer is arranged below the first isolation layer and seals each reformed layer; a layered ball-dropping sliding sleeve arranged above the second packer, the layered ball-dropping sliding sleeve is used for fracturing the reformed channel; wherein, when reforming and testing operations are carried out, the reformed layer section is reformed and tested in sequence from bottom to top through the second packer and the layered ball-dropping sliding sleeve.

[0004] However, the existing technology is mainly aimed at stratified fracturing and testing of new wells and exploration and evaluation wells, and cannot solve the problem of interlayer "backflow" due to the pressure difference between layers when reserving old layers during layer inspection and perforation. Therefore, for old wells with large pressure differences between new and old layers, the field application is limited. Summary of the invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a gas well layer inspection and perforation repair layered fracturing and testing integrated pipe string and testing method, so as to solve the problem of interlayer "backflow" due to the pressure difference between layers in the old layer section retained during layer inspection and perforation repair, as well as the problem of new layer production capacity testing, so as to give full play to the potential of different reservoirs in the gas well.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a gas well layer inspection and perforation repair layered fracturing and testing integrated pipe string, comprising an oil pipe, on which a gas lift sleeve, a first compression packer, a production sleeve, a second compression packer, a ball-dropping sleeve, an expansion packer and a constant pressure sleeve are sequentially arranged from top to bottom;

[0008] The first compression packer and the second compression packer are used to plug the old layer section;

[0009] The expandable packer is arranged between two adjacent unconverted layer sections.

[0010] In the specific implementation process, a safety joint is arranged between the gas lift sliding sleeve and the first compression packer.

[0011] In the specific implementation process, a hydraulic anchor is arranged between the ball-dropping sliding sleeve and the expansion packer.

[0012] In the specific implementation process, a sleeve seating joint is arranged below the pitching sleeve.

[0013] In the specific implementation process, a well gauge is arranged at the lower part of the oil pipe.

[0014] In the specific implementation process, a plug is provided at the lower end of the oil pipe.

[0015] In a specific implementation process, the depth of the production sleeve is located within the old layer section.

[0016] In a specific implementation process, the depth of the first compression packer is located above the old layer interval;

[0017] The depth of the second compression packer is located below the old layer interval.

[0018] The present invention also provides a method for testing a gas well layer checking, perforating and layered fracturing and testing integrated pipe string, based on any one of the gas well layer checking, perforating and layered fracturing and testing integrated pipe strings, comprising the following steps:

[0019] S1: After the oil pipe is lowered to the predetermined depth, a ball is thrown into the constant pressure sleeve to build up pressure to seal the first compression packer and the second compression packer. When the pressure reaches 30-34 MPa, the constant pressure sleeve is opened, the oil pipe is connected to the second new layer, and the second new layer is subjected to fracturing transformation;

[0020] S2: Throw the ball to open the ball sleeve, perform fracturing on the first new layer, and implement fracturing operation. After the first and second new layers are transformed, they will be tested together;

[0021] S3: When drainage is blocked after transformation, gas lift is performed through the gas lift sleeve to facilitate drainage; the flow pressure of the first new layer and the second new layer is tested, and then the well is shut in to measure the recovery pressure and static pressure;

[0022] S4: After the first and second new layers of the gas well have been producing for a period of time, when the pressure difference between the old layer and the first and second new layers is not much, the production sleeve is opened by wireline operation, the old layer is connected with the oil pipe to restore the production capacity, and the old layer is produced at the same time as the first and second new layers;

[0023] S5: When liquid accumulation occurs during the later stage of production, gas lift is used to resume production through the gas lift sleeve.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention provides a gas well layer inspection and hole filling layered fracturing and testing integrated pipe string and testing method, which solves the problem that the current main process of gas field layer inspection and hole filling adopts mechanical isolation layered fracturing. When the old layer is not the lowest layer, there is interlayer interference in the post-pressure drainage process, which affects the production capacity of the new layer. When the new and old layers are produced at the same time in the later stage, there is a difference in interlayer pressure, and the high-pressure layer "backflows" to the low-pressure layer in the combined production, which limits the production capacity of the gas well. After the new layer segment is fracturing and reformed with the above-mentioned pipe string, production and testing can be directly sought, avoiding the complicated pipe string lifting and related testing tools, shortening the testing operation time, and saving operation costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the integrated pipe string structure for layer checking, hole filling, layered fracturing and testing of a gas well according to the present invention;

[0027] Among them: 1-oil pipe; 2-gas lift sleeve; 3-safety joint; 4-first compression packer; 5-production sleeve; 6-second compression packer; 7-ball sleeve; 8-hydraulic anchor; 9-expansion packer; 10-sleeve landing joint; 11-well gauge; 12-constant pressure sleeve; 13-plug; A-old layer; B1-first new layer; B2-second new layer. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0030] The following is combined with Figure 1 The present invention is described in further detail:

[0031] See also Figure 1 The present invention provides an integrated string for layer inspection, hole filling, stratified fracturing and testing of gas wells, which includes an oil pipe 1, and a plug 13 is arranged at the lower end of the oil pipe 1; an expansion packer 9, namely a K344 packer, is arranged at the lower part of the oil pipe 1, and a first compression packer 4 and a second compression packer 6Y441 packer are used to plug the old layer section. In the specific implementation process, there are three reformed layer sections, the first reformed layer section is the reformed old layer section A, the second reformed layer section is the unreformed old layer, namely the first new layer B1, and the third reformed layer section is the unreformed old layer, namely the second new layer B2. The K344 packer, namely the expansion packer 9, is arranged between the second reformed layer section and the third reformed layer section, namely the first new layer B1 and the second new layer B2. A ball-throwing sleeve 7 is also arranged on the oil pipe 1, and the ball-throwing sleeve 7 is arranged below the second compression packer 6, which is used for the fracturing reformation channel of the first new layer B1.

[0032] Among them, when carrying out the transformation and testing operations, after the oil pipe 1 is lowered to a predetermined depth, a ball is dropped at the constant pressure sleeve 12 to build up pressure so that the expansion packer 9 and the Y441 packer, i.e., the first compression packer 4, are sealed. When the pressure reaches 30-34 MPa, the constant pressure sleeve 12 is opened, and the second new layer B2 is subjected to fracturing transformation. The ball is continued to be dropped to open the ball-dropping sleeve 7, and the first new layer B1 is transformed. After the transformation, the first new layer B1 and the second new layer B2 are tested together.

[0033] In the specific implementation process, the Y441 packer, i.e. the first compression packer 4, and the Y441 packer, i.e. the second compression packer 6, work by hydraulic seating, bidirectional anchoring, lifting and lowering the pipe string step by step. The expansion packer 9 is a k344 packer, and both packers are seated by pressurizing the oil pipe 1.

[0034] In the specific implementation process, a constant pressure sleeve 12 is provided at the lower end of the oil pipe 1, and the constant pressure sleeve 12 is used to hold the pressure to seal the packer, and the opened sleeve provides a fracturing channel for the lower layer. In this embodiment, the ball-dropping sleeve 7 and the balls used for the packer sealing are both soluble balls.

[0035] In the specific implementation process, ports are opened on the main body of the ball-throwing sleeve 7. The soluble ball is thrown into the ball-throwing sleeve 7, and the sleeve core moves down into the sleeve landing joint 10, exposing the ports on the main body to form a fracturing channel for the layer.

[0036] In the specific implementation process, the well clearing gauge 11 is used to scrape off the burrs of the wellbore. When the old layer is on the top, the well clearing position is generally to the upper end of the old layer. The new layer for layer checking and hole filling is not reached at the lower end of the old layer. The well clearing gauge 11 is mainly used to deal with the lower wellbore where the old layer is not reached.

[0037] In the specific implementation process, a production sleeve 5 is arranged below the Y441 packer, i.e., the first compression packer 4. After the new layer of the gas well has produced for a period of time and the pressure difference between the new layer and the old layer is not large, the sleeve switch is opened by wire operation, and the old layer is connected to the oil pipeline to restore production capacity, so that the new and old layers can produce at the same time.

[0038] In the specific implementation process, a safety joint 3 is arranged above the Y441 packer, i.e., the first compression packer 4. The safety joint 3 is to prevent the packer from being unsealed or sand settling on the packer, which may cause a drill stuck accident. The drill tool and tubing above the safety joint can be pulled out from the safety joint to ensure the safety and stability of the pipe string. In the specific implementation process, the safety joint 3 is an inverted safety valve joint, which is inverted and released when the pipe string cannot be pulled out, thereby ensuring the safety of the pipe string.

[0039] In the specific implementation process, an air lift sleeve 2 is arranged above the safety joint 3. When the air lift sleeve 2 is closed, the annulus of the oil pipe 1 and the well wall are not connected. It is generally difficult to drain the layer inspection and perforation wells, and the gas production is relatively low during production, which is prone to liquid accumulation. The air lift sleeve 2 is convenient for gas lift drainage and resumption of production in the later stage of gas well production.

[0040] The use of a gas well layer inspection and perforation repair layered fracturing and testing string of the present invention can economically, conveniently, efficiently and reliably complete the new layer inspection and perforation repair transformation and testing, eliminating the need for bridge plug sealing and drilling plug procedures, which is beneficial to well control safety, reduces the number of times of pulling in and out the string and well pressure, shortens the occupancy time of the operating machine, and saves operating costs.

[0041] A further improvement of the present invention is that the Y441 packers used in the first compression packer 4 and the second compression packer 6 are compression packers, which will not automatically unseal after fracturing compared with expansion packers, effectively avoiding the "backflow" phenomenon of new and old layer sections caused by the automatic unsealing of the original expansion packer.

[0042] A further improvement of the present invention is that the expandable packer 9K344 packer is used for new layer stratified fracturing. After the fracturing transformation, production and testing can be directly carried out, avoiding the complicated pipe string tripping and related testing tools, shortening the testing operation time and saving the operation cost.

[0043] A further improvement of the present invention is that a gas lift sleeve 2 is provided on the tubing string. When the pressure outside the tubing string is greater than 4-6 MPa inside the tubing string, the gas lift sleeve 2 is opened, the oil casing is connected, and gas lift operations can be performed through the gas lift sleeve, which is convenient for gas well gas testing and drainage and gas lift and production recovery drainage in the later stage of the gas well.

[0044] The above-mentioned testing method of the integrated string for layered fracturing and testing for gas well layer checking and perforation repair is as follows:

[0045] S1: After the oil pipe 1 is lowered to a predetermined depth, a ball is thrown into the constant pressure sleeve 12 to build up pressure to seal the first compression packer 4 and the second compression packer 6. When the pressure reaches 30-34 MPa, the constant pressure sleeve 12 is opened, the oil pipe 1 is connected to the second new layer, and the second new layer is subjected to fracturing transformation;

[0046] S2: Throwing a ball to open the ball-throwing sliding sleeve 7, and fracturing the corresponding first new layer, and implementing the fracturing operation. After the first new layer and the second new layer are transformed, they are tested together;

[0047] S3: When the drainage is blocked after the transformation, gas lift is performed through the gas lift sleeve 2 to facilitate the drainage; the flow pressure of the first new layer and the second new layer is tested, and then the well is shut in to measure the recovery pressure and static pressure;

[0048] S4: After the first and second new layers of the gas well have been producing for a period of time, when the pressure difference between the old layer and the first and second new layers is not much, the production sleeve 5 is opened by wireline operation, the old layer is connected with the oil pipe 1 to restore the production capacity, and the old layer is produced simultaneously with the first and second new layers;

[0049] S5: During the later production process, when liquid accumulation occurs, gas lift sleeve 2 is used to drain the liquid and resume production.

[0050] Example

[0051] The present embodiment provides an integrated tubing string for layer inspection, perforation repair, stratified fracturing and testing in a gas well, which is mainly composed of an oil pipe 1, a gas lift sleeve 2, a safety joint 3, a first compression packer 4, namely a Y441 packer, a production sleeve 5, a second compression packer 6, namely a Y441 packer, a ball-dropping sleeve 7, a hydraulic anchor 8, an expansion packer 9, namely a K344 packer, a sleeve landing joint 10, a well-drilling gauge 11, a constant-pressure sleeve 12, and a plug 13.

[0052] The specific installation position of the above structure is as follows:

[0053] An air lift sleeve 2 is arranged on the upper part of the oil pipe 1; a safety joint 3 is arranged below the air lift sleeve 2; a first compression packer 4, i.e., a Y441 packer, is arranged below the safety joint 3. The depth of the first compression packer 4, i.e., the Y441 packer, is above the upper old layer, and is used to prevent the annular space fluid from entering the old layer section when the fracturing transformation is balanced; a production sleeve 5 is arranged below the first compression packer 4, i.e., the Y441 packer, and the depth of the production sleeve 5 is in the middle of the upper old layer section. A second compression packer 6, i.e., the Y441 packer, is arranged below the production sleeve 5. The depth position of the packer 6, i.e., the Y441 packer, is between the upper old layer section and the lower new layer section B1; a ball-dropping sleeve 7 is arranged below the second compression packer 6, i.e., the Y441 packer; a hydraulic anchor 8 is arranged below the ball-dropping sleeve 7, and an expandable packer 9 is arranged below the hydraulic anchor 8. The depth position of the expandable packer 9 is between the new layer section B1 and the new layer section B2; a sleeve landing joint 10 is arranged below the expandable packer 9, and a well-drilling gauge 11 is arranged below the sleeve landing joint 10. The lower end of the well-drilling gauge 11 is connected to a constant-pressure sleeve 12, and a plug 13 is arranged below the constant-pressure sleeve 12.

[0054] This embodiment uses a process string with a Y441 packer to isolate the old layer and a K344 packer to isolate the new layer. During the process, the Y441 packer that isolates the old layer is lifted and unsealed in a set state, isolating the old layer from the new layer, effectively avoiding the "backflow" phenomenon of the new and old layer sections caused by the automatic unsealing of the original expansion packer. The above-mentioned device can be used to directly ask for production and test after the layered fracturing transformation is completed, avoiding the complicated lifting of related testing tools, shortening the test operation time, and saving operation costs. After the new layer of the gas well has produced for a period of time, when the pressure difference between the new layer and the old layer is not large, the production sleeve 5 is opened by wire operation, and the old layer is connected to the oil pipe to restore production capacity, ensuring that the new layer's production capacity is effectively utilized while increasing the old layer's production capacity contribution.

[0055] The gas lift sleeve 2 set in the string is opened when the pressure outside the string is greater than 4-6MPa inside the string, and the oil casing is connected. Gas lift operation can be carried out through the gas lift sleeve 2, which is convenient for gas well gas test and drainage and gas lift recovery and drainage in the later stage of gas well. The above string solves the current layer inspection and perforation repair process, the interference between the new and old layers during the measures affects the gas well production capacity, and the new layer section production capacity test of the layer inspection and perforation repair is convenient for the later gas well measures and production.

[0056] The present embodiment also provides a testing method based on the integrated string of layered fracturing and testing for gas well layer inspection and perforation repair. The first step is to drill down to the designed depth, drop a ball into the constant pressure sleeve 12 to build up pressure to seal the Y441 packer, open the constant pressure sleeve 12, connect the oil pipe with the second new layer B2, and perform fracturing transformation on the layer section.

[0057] Step 2: Throw the ball to open the ball-throwing sleeve 7, i.e., the fracturing channel of the first new layer B1, and implement the fracturing operation to complete the split-pressure test.

[0058] Step 3: When drainage is blocked after transformation, perform gas lift through gas lift sleeve 2 to facilitate drainage; test the flow pressure of the new layer, and then shut in the well to measure the recovery pressure and static pressure.

[0059] Step 4: After the new layer of the gas well has produced for a period of time, when the pressure difference between the new layer and the old layer section A is not large, the production sleeve 5 is opened by wire operation, the old layer section A is connected to the oil pipe to restore the production capacity, and the new and old layers can produce at the same time;

[0060] Step 5: When liquid accumulation occurs during the later production process, gas lift sleeve 2 is used to drain the liquid and resume production.

[0061] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A gas well layer inspection, perforation repair, layered fracturing and testing integrated pipe string, characterized in that: The oil pipe (1) comprises an air lift sleeve (2), a first compression packer (4), a production sleeve (5), a second compression packer (6), a ball-dropping sleeve (7), an expansion packer (9) and a constant pressure sleeve (12) which are arranged in order from top to bottom. The first compression packer (4) and the second compression packer (6) are used to plug the old layer section; The expandable packer (9) is arranged between two adjacent unconverted layer sections.

2. The integrated pipe string for layer inspection, perforation repair, layered fracturing and testing of gas wells according to claim 1, characterized in that: A safety joint (3) is provided between the air lift sliding sleeve (2) and the first compression packer (4).

3. The integrated pipe string for layer inspection, perforation repair, layered fracturing and testing of a gas well according to claim 1, characterized in that: A hydraulic anchor (8) is arranged between the ball-dropping sliding sleeve (7) and the expansion packer (9).

4. The integrated pipe string for layer inspection, perforation repair, layered fracturing and testing of a gas well according to claim 1, characterized in that: A sliding sleeve seating joint (10) is arranged below the pitching sliding sleeve (7).

5. The integrated pipe string for layer inspection, perforation repair, layered fracturing and testing of a gas well according to claim 1, characterized in that: A well gauge (11) is provided at the lower part of the oil pipe (1).

6. The integrated pipe string for layer checking, perforation repair, layered fracturing and testing of a gas well according to claim 1, characterized in that: A plug (13) is provided at the lower end of the oil pipe (1).

7. The integrated pipe string for layer checking, perforation repair, layered fracturing and testing of a gas well according to claim 1, characterized in that: The depth of the production sleeve (5) is within the old layer interval.

8. The integrated pipe string for layer inspection, perforation repair, layered fracturing and testing of a gas well according to claim 1, characterized in that: The depth of the first compression packer (4) is located above the old layer interval; The depth of the second compression packer (6) is located below the old layer interval.

9. A method for testing a gas well layer inspection, perforation repair, layered fracturing and testing integrated pipe string, based on the gas well layer inspection, perforation repair, layered fracturing and testing integrated pipe string according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: After the oil pipe (1) is lowered to a predetermined depth, a ball is thrown into the constant pressure sleeve (12) to build up pressure so that the first compression packer (4) and the second compression packer (6) are set, and when the pressure reaches 30-34 MPa, the constant pressure sleeve (12) is opened, the oil pipe (1) is connected to the second new layer, and the second new layer is subjected to fracturing transformation; S2: Throwing a ball to open the ball-throwing sleeve (7), and performing fracturing transformation on the first new layer, and carrying out fracturing operation. After the transformation of the first new layer and the second new layer, a joint test is conducted; S3: When the drainage is blocked after the transformation, gas lift is performed through the gas lift sleeve (2) to facilitate the drainage; the flow pressure of the first new layer and the second new layer is tested, and then the well is shut in to measure the recovery pressure and static pressure; S4: After the first new layer and the second new layer of the gas well have been producing for a period of time, when the pressure difference between the old layer and the first new layer and the second new layer is not much, the production sleeve (5) is opened by wire operation, the old layer is connected with the oil pipe (1) to restore the production capacity, and the old layer and the first new layer and the second new layer are produced simultaneously; S5: When liquid accumulation occurs during the later stage of production, gas lift is performed to resume production through the gas lift sleeve (2).

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