Injection and production combined well washing and oil layer protecting process pipe column and operation method of injection and production combined well washing and oil layer protecting process pipe column

Abstract

The invention discloses an injection and production combined well washing and oil layer protecting process pipe column and an operation method. The process pipe column comprises a full-bore gas anchor, a core-free valve, a first screen pipe nipple, a soluble ball seat, a well washing self-sealing device, a second screen pipe nipple and a perforating gun which are sequentially connected from top to bottom. The core-free valve is used for being in an open state during perforation operation and well washing operation and being in a closed state during oil extraction operation; a liquid inlet hole is formed in the side surface of the full-bore gas anchor; the soluble ball seat is used for being vacant during perforation operation and oil extraction operation, containing the soluble ball during well washing operation and installing the adjustable rod type pump during oil extraction operation. The device is ingenious in structure, low in cost, easy to operate and good in stability, and achieves the beneficial effects of protecting an oil and gas reservoir from being polluted by well washing liquid in the well washing process under the condition of injection and production combination.

Description

Technical Field

[0001] The invention relates to the field of oil field production engineering, in particular to a process pipe string for well washing and oil layer protection by combined shooting and production. Background Art

[0002] In the early stage of development, volatile oil reservoirs have good self-flowing ability and single-well daily production. As the crude oil in the reservoir is continuously produced, the reservoir formation pressure will gradually decrease, resulting in a decrease in the permeability of the reservoir formation. For low-permeability volatile oil reservoirs in the later stage, due to the obvious pressure-sensitive effect of low-permeability reservoirs, if the well-washing fluid flows into the formation during the well-washing operation, it will cause oil layer pollution and a further rapid decrease in reservoir permeability, resulting in a decrease in the production volume, production capacity and recovery rate of the production well. Therefore, it is urgent to develop an effective and practical process string and corresponding operation method to achieve the completion of perforation and oil production while avoiding the pollution of oil and gas layers by the well-washing fluid. Summary of the invention

[0003] In view of the above problems, the present invention is proposed to provide a drilling and production combined well washing and oil layer protection process string and operation method that overcome the above problems or at least partially solve the above problems.

[0004] In a first aspect, an embodiment of the present invention provides a drilling and production combined well-washing and oil layer protection process string, comprising:

[0005] A drilling and production combined well-washing and oil layer protection process string, characterized by comprising:

[0006] The full-bore air anchor, coreless valve, first screen tube nipple, soluble ball seat, well-washing self-sealing device, second screen tube nipple and perforating gun are connected in sequence from top to bottom;

[0007] The coreless valve is connected to the lower inlet of the full-diameter air anchor, and the coreless valve is used to be in an open state during perforation operations and well washing operations, and in a closed state during oil production operations;

[0008] The side surface of the full-diameter air anchor is provided with a liquid inlet hole;

[0009] The soluble ball seat is arranged between the first screen tube nipple and the well-washing self-sealing device. The soluble ball seat is used to be empty during perforating operations and oil production operations, and to accommodate the soluble ball during well-washing operations.

[0010] In one embodiment, the process string further comprises: multiple sections of tubing;

[0011] The multi-section oil pipe is threadedly connected from top to bottom with the full-bore air anchor, the first screen tube short section, the soluble ball seat, the well-washing self-sealing device, the second screen tube short section and the perforating gun.

[0012] In one embodiment, the process pipe string further comprises: an adjustable rod pump, wherein the adjustable rod pump is disposed in the oil pipe above the full-bore air anchor.

[0013] In one embodiment, the well-washing self-sealing device is threadedly connected to the outer wall of the oil pipe between the soluble ball seat and the second screen tube nipple.

[0014] In one embodiment, the cross-sectional area of ​​the soluble ball seat is larger than the cross-sectional area of ​​the oil pipe connected thereto.

[0015] In one embodiment, the coreless valve has no valve core during perforating operations and well washing operations, and has a valve core during oil production operations.

[0016] In a second aspect, an embodiment of the present invention provides a method for performing related operations using a well-washing and oil layer protection process string as described above, including:

[0017] The process pipe string is lowered into the designed position in the oil well, and the perforating gun is started to perform perforating operation on the oil and gas layer;

[0018] After the perforation operation is completed, the soluble ball is put into the process pipe string, so that the soluble ball falls onto the soluble ball seat, and the well washing operation is performed;

[0019] After the well washing operation is completed, the coreless valve is closed, and the adjustable rod pump is lowered into the process pipe string to carry out oil production operations.

[0020] In one embodiment, starting the perforating gun to perform perforating operations on the oil and gas layer includes:

[0021] During the perforating operation, an ignition rod is put into the process pipe string to start the perforating gun.

[0022] In one embodiment, the coreless valve is closed by inserting a valve core into the coreless valve to close the coreless valve.

[0023] In one embodiment, during the oil production operation, the adjustable rod pump adjusts the pumping depth of the adjustable rod pump by lifting and lowering the sucker rod according to the dynamic liquid level depth in the oil pipe above the full-bore air anchor.

[0024] The beneficial effects of the above technical solution provided by the embodiment of the present invention include at least:

[0025] The above-mentioned perforating and production-linked well-washing and oil layer protection process string and operation method provided by the embodiment of the present invention, the above-mentioned process string, from top to bottom, has the main components connected in sequence including a full-diameter gas anchor, a coreless valve, a first screen tube short section, a soluble ball seat, a well-washing self-sealing device, a second screen tube short section and a perforating gun. The above-mentioned process string can be used to continuously complete perforating operations, well-washing operations and oil production operations. Before the perforating operation, the main components of the above-mentioned process pipe string and the axial direction of the oil pipe string composed of multiple oil pipes are internally connected; after the perforating operation is completed, during the well washing operation, the soluble ball is contained on the soluble ball seat, and the soluble ball and the well washing self-sealing device separate the path of the well washing fluid flowing to the lower part of the annulus and the lower part of the oil pipe string, so as to avoid the well washing fluid from entering the oil and gas layer to cause pollution, and even cause a sharp drop in the permeability of the oil and gas layer; after the well washing operation is completed, during the oil production operation, the centerless valve is in a closed state, and the soluble ball has been dissolved, and the production fluid can smoothly pass through the soluble ball seat from the oil pipe string, enter the annulus through the first screen pipe short section, and then complete the oil and gas separation through the lateral liquid inlet of the full-bore gas anchor, and finally be lifted to the ground by the adjustable rod pump above the full-bore gas anchor. The process string provided in the embodiment of the present invention has an ingenious structure, low cost, simple operation and good stability. By utilizing the innovation of the structure of the process string, the well washing operation in the case of perforation and production is realized. The well washing operation in the embodiment of the present invention is carried out almost simultaneously with the perforation operation and the oil production operation. The entire operation process is completed in one go, saving economic and time costs. In addition, according to the characteristics of the oil wells in actual working conditions, a variety of tools can be provided to realize or improve other operation functions or requirements.

[0026] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0027] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0029] Figure 1 It is a schematic structural diagram of a well-washing and oil layer protection process string (during perforating operation) in an embodiment of the present invention;

[0030] Figure 2 It is a process string for well-washing and oil-layer protection in the embodiment of the present invention (during well-washing operation);

[0031] Figure 3It is a process string for well washing and protecting oil layer in the embodiment of the present invention (during oil production operation);

[0032] Figure 4 The present invention is a flowchart of an operation method of a well-washing and oil-layer protection process string based on the combined operation of shooting and production in an embodiment of the present invention.

[0033] 1. Full-bore gas anchor 2. Coreless valve 3. First screen tube short section 4. Soluble ball seat 5. Well flushing self-sealing device 6. Second screen tube short section 7. Perforating gun 8. Adjustable rod pump 91. First oil pipe 92. Second oil pipe 93. Third oil pipe 94. Fourth oil pipe 95. Fifth oil pipe 10. Oil pipe string 11. Perforating gun 12. Oil and gas layer 13. Soluble ball 14. Valve core. DETAILED DESCRIPTION

[0034] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0035] The embodiment of the present invention provides a drilling and production combined well washing and oil layer protection process string, comprising:

[0036] The full-bore air anchor, coreless valve, first screen tube nipple, soluble ball seat, well-washing self-sealing device, second screen tube nipple and perforating gun are connected in sequence from top to bottom;

[0037] The coreless valve is connected to the lower inlet of the full-bore air anchor. The coreless valve is in an open state during perforation and well washing operations, and is in a closed state during oil production operations. The full-bore air anchor has a liquid inlet hole on its side.

[0038] The soluble ball seat is arranged between the first screen tube short section and the well-washing self-sealing device. The soluble ball seat is used to be empty during perforating and oil production operations and to accommodate the soluble ball during well-washing operations.

[0039] The process string for well washing and oil layer protection provided by the embodiment of the present invention mainly comprises: a full-bore gas anchor 1, a coreless valve 2, a first screen tube short section 3, a soluble ball seat 4, a well washing self-sealing device 5, a second screen tube short section 6, a perforating gun 7 and an adjustable rod pump 8. By using the process string in the embodiment of the present invention, well washing operations can be carried out in the case of combined shooting and production, and the oil and gas layers can be protected from pollution.

[0040] The process string in the embodiment of the present invention is used in conjunction with perforating operations, well washing operations and oil production operations. In different operation processes, some of its components or structural forms are slightly different. In order to better explain the process and beneficial effects of the process string in the embodiment of the present invention, the structure, composition and process of the process string are explained respectively through different operation stages.

[0041] The process string in the embodiment of the present invention can continuously perform and complete the perforation operation, well washing operation and oil production operation in sequence.

[0042] During the perforation operation, the structure of the process string in the embodiment of the present invention is as follows: Figure 1 At this time, the structure of the process pipe string includes a plurality of oil pipes in addition to the main components, but the adjustable rod pump 8 is not installed.

[0043] For example, the process string includes, from top to bottom, the first oil pipe 91, the full-bore gas anchor 1, the coreless valve 2, the second oil pipe 92, the first screen tube short section 3, the third oil pipe 93, the soluble ball seat 4, the fourth oil pipe 94, the well washing self-sealing device 5, the second screen tube short section 6, the fifth oil pipe 95 and the perforating gun 7. The above main components (except the adjustable rod pump 8) and the multiple oil pipes are connected together by threaded fixing to form an oil pipe string 10. It can be said that the main components of the process string can be indirectly connected from top to bottom, or these main components can be directly connected.

[0044] During the perforating operation, for example, in order to ensure that the ignition rod 11 dropped from the upper entrance of the oil pipe string 10 reaches the position of the perforating gun 7 smoothly, and then the perforating gun 7 is started, Figure 1 The oil pipe string 10 in the oil pipe string 10 is axially connected. For example, the full-bore air anchor 1 has an axially connected upper and lower inlet and outlet, and the oil and gas inlet is set at a lateral position; the coreless valve 2 is threadedly connected to the lower inlet of the full-bore air anchor 1. Although the coreless valve 2 has a matching valve core, it is not installed at this time and the interior is hollow; the soluble ball seat 4 is empty and does not include a soluble ball. Its interior is also hollow. The movement route of the ignition rod 11 in the oil pipe string 10 is as follows Figure 1 Indicated by the dashed arrow. Figure 1 The oil pipe string 10 is pre-assembled on the ground and then lowered into the designed position.

[0045] After the perforation operation is completed, the well washing operation is required. The structural form of the process string during the well washing operation can be referred to Figure 2 At this time, the process pipe column is not installed with the adjustable rod pump 8, the coreless valve 2 still does not include a valve core, but the soluble ball seat 4 contains a soluble ball. The soluble ball can be dropped from the upper inlet of the oil pipe string 10 so that it is just seated on the soluble ball seat 4.

[0046] When performing a well-washing operation, for example, the well-washing fluid first enters the annulus from above. Due to the setting of the well-washing self-sealing device 5, the well-washing fluid cannot flow downward when it reaches the well-washing self-sealing device 5. The well-washing self-sealing device 5 is threadedly connected to the outer wall of the fourth oil pipe 94, which plays a role in blocking the well-washing fluid from continuing to flow to the lower part of the annulus. Therefore, the well-washing fluid can only enter the oil pipe string 10 through the sieve holes on the first screen tube short section 3. Since the soluble ball 13 is accommodated on the soluble ball seat 4, the cross-sectional area of ​​the soluble ball seat 4 is larger than the cross-sectional area of ​​the connected fourth oil pipe 94, or the diameter of the soluble ball 13 is larger than the inner diameter of the fourth oil pipe 94. The soluble ball 13 also plays a role in blocking the well-washing fluid from continuing to flow to the lower part of the oil pipe string 10.

[0047] Since the coreless valve 2 (without valve core) and the full-bore air anchor 1 connected thereto are internally connected, the well washing fluid that continuously enters the oil pipe string 10 can only flow toward the following path, namely: the second oil pipe 92 on the upper part of the first screen tube short section 3, that is, the well washing fluid passes through the annulus, the first screen tube short section 3, the coreless valve 2 (without valve core), the lower inlet of the full-bore air anchor 1, and finally returns from the upper outlet of the full-bore air anchor 1, thereby completing the well washing work.

[0048] In addition, during the well washing operation, the perforating gun 7 has opened the oil and gas layer 12, and the production fluid passes through the casing and the cement ring from the oil and gas layer 12 into the annulus. Due to the limitation of the well washing self-sealing device 5, the production fluid cannot continue to move upward in the annulus and can only enter the oil pipe string 10 through the sieve holes on the second screen pipe short section 6. Similarly, due to the limitation of the soluble ball seat 4 (containing the soluble ball 13), the production fluid flowing upward in the oil pipe string 10 is blocked from flowing upward.

[0049] It can be seen that the well-washing self-sealing device 5 and the soluble ball seat 4 (containing the soluble ball 13) completely isolate the well-washing fluid from the production fluid, preventing the well-washing fluid from entering the oil and gas layer 12, so as to avoid contamination of the oil and gas layer 12 or a sharp drop in permeability, that is, while successfully completing the well-washing operation, the oil and gas layer 12 is also protected. Figure 2 The flow path of the well washing fluid is shown by the dotted arrows, and the flow path of the production fluid is shown by the solid arrows.

[0050] After the well washing operation is completed, the oil production operation is carried out. The structure of the process pipe string during the oil production operation is as follows: Figure 3 At this time, the process column is installed with an adjustable rod pump 8, the coreless valve 2 has a valve core 14 matched therewith, and the soluble ball seat 4 is empty and does not contain the soluble ball 13 (which has been dissolved in the aforementioned process).

[0051] The process includes: the valve core 14 can be put in from the upper inlet of the oil pipe string 10, so that it is located in the coreless valve 2, which plays the role of blocking the lower inlet of the full-bore air anchor 1. After the soluble ball 13 put in during the previous well washing operation is dissolved, the adjustable rod pump 8 is put in from the oil pipe string 10, so that it is located in the first oil pipe 91 above the full-bore air anchor 1, and then the oil production operation can be carried out.

[0052] When the valve core 14 is put in to close the coreless valve 2, the operation needs to be performed after the well washing operation is completed and before the soluble ball 13 is dissolved.

[0053] like Figure 3 As shown, during the oil production operation, since the soluble ball seat 4 is vacant at this time, the upward flow channel of the produced liquid in the oil pipe string 10 previously restricted by the soluble ball 13 has been opened, so the produced liquid can continue to flow upward through the soluble ball seat 4. When it reaches the coreless valve 2, due to the blocking effect of the valve core 14, the axial lower entrance of the full-bore gas anchor 1 is closed at this time, and the produced liquid that continuously gushes out of the oil and gas layer can only enter the annulus through the sieve holes on the first sieve tube short section 3. Since the oil and gas inlet of the full-bore gas anchor 1 is set at a lateral position, the upward moving produced liquid can enter the full-bore gas anchor 1 from the lateral inlet, and continue to flow through the full-bore gas anchor 1. After that, under the action of the adjustable rod pump 8, the produced liquid is lifted to the ground. Before the produced liquid enters the adjustable rod pump 8, part of the gas in it is separated by the full-bore gas anchor 1, reducing the impact on the adjustable rod pump 8. Figure 3 The flow path of the produced liquid is shown by the solid arrow.

[0054] The installed adjustable rod pump 8 can adjust its own immersion depth according to the dynamic liquid level depth of the produced liquid in the first oil pipe 91. For example, by lifting and lowering the sucker rod, the pump depth can be adjusted without lifting and lowering the oil pipe during operation. The operation is simple and the oil production efficiency is high.

[0055] At this point, the perforating operation, well washing operation and oil production operation have been completed successively. The process string structure in the embodiment of the present invention is simple and the cost is low. The process flow is ingeniously conceived, which can meet the requirements of protecting the oil and gas layers during the well washing process. At the same time, compared with the existing technology, the well washing operation is carried out almost simultaneously with the perforating and production operation, which can greatly shorten the construction period and save construction costs.

[0056] Based on the same inventive concept, an embodiment of the present invention also provides an operating method for using a process string for well flushing and oil layer protection by combining shooting and production. Since the principle of this method is similar to the aforementioned process string for well flushing and oil layer protection by combining shooting and production, the implementation of this method can refer to the implementation of the aforementioned device, and the repeated parts will not be repeated.

[0057] The embodiment of the present invention provides an operation method using the aforementioned shooting and production combined well washing and oil layer protection process string, referring to Figure 4 As shown, including:

[0058] S41, lowering the process pipe string into the designed position in the oil well, starting the perforating gun, and performing perforating operations on the oil and gas layer;

[0059] S42, after the perforation operation is completed, a soluble ball is put into the process pipe string, so that the soluble ball falls on the soluble ball seat, and the well washing operation is performed;

[0060] S43. After completing the well washing operation, close the coreless valve and lower the adjustable rod pump into the process pipe string to carry out oil production operations.

[0061] The operation method provided by the embodiment of the present invention is adapted to the structural form of the process pipe string at different operation stages, and can continuously complete perforation operations, well washing operations and oil production operations.

[0062] In one embodiment, during the perforating operation, since the oil pipe string 10 is internally connected at this time, an ignition rod is put into the process pipe string to start the perforating gun 7.

[0063] In one embodiment, during oil production operations, a valve core 14 matching the coreless valve 2 is inserted into the process pipe column to close the coreless valve 2 .

[0064] In one embodiment, the adjustable rod pump adjusts the pumping depth of the adjustable rod pump by lifting and lowering the sucker rod according to the dynamic liquid level depth in the oil pipe above the full-bore air anchor.

[0065] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A drilling and production combined well washing and oil layer protection process string, characterized in that: include: The full-bore air anchor, coreless valve, first screen tube nipple, soluble ball seat, well-washing self-sealing device, second screen tube nipple and perforating gun are connected in sequence from top to bottom; The coreless valve is connected to the lower inlet of the full-diameter air anchor, and the coreless valve is used to be in an open state during perforation operations and well washing operations, and in a closed state during oil production operations; The side surface of the full-diameter air anchor is provided with a liquid inlet hole; The soluble ball seat is arranged between the first screen tube nipple and the well-washing self-sealing device. The soluble ball seat is used to be empty during perforating operations and oil production operations, and to accommodate the soluble ball during well-washing operations.

2. The process column according to claim 1, characterized in that: The process pipe string also includes: multiple sections of oil pipe; The multi-section oil pipe is threadedly connected from top to bottom with the full-diameter air anchor, the first screen tube short section, the soluble ball seat, the well-washing self-sealing device, the second screen tube short section and the perforating gun.

3. The process column according to claim 2, characterized in that: The process pipe string further comprises: an adjustable rod pump, and the adjustable rod pump is arranged in the oil pipe above the full-bore air anchor.

4. The process column according to claim 2, characterized in that: The well-washing self-sealing device is threadedly connected to the outer wall of the oil pipe between the soluble ball seat and the second screen pipe nipple.

5. The process column according to claim 2, characterized in that: The cross-sectional area of ​​the soluble ball seat is larger than the cross-sectional area of ​​the oil pipe connected thereto.

6. The process column according to any one of claims 1 to 5, characterized in that: The coreless valve has no valve core during perforation operation and well washing operation, and has a valve core during oil production operation.

7. An operation method using the well-washing and oil layer protection process string of any one of claims 1 to 6, characterized in that: include: The process pipe string is lowered into the designed position in the oil well, and the perforating gun is started to perform perforating operation on the oil and gas layer; After the perforation operation is completed, the soluble ball is put into the process pipe string, so that the soluble ball falls onto the soluble ball seat, and the well washing operation is performed; After the well washing operation is completed, the coreless valve is closed, and the adjustable rod pump is lowered into the process pipe string to carry out oil production operations.

8. The process column according to any one of claims 7, characterized in that: Starting the perforating gun to perform perforating operations on the oil and gas layer includes: During the perforating operation, an ignition rod is put into the process pipe string to start the perforating gun.

9. The method according to claim 7, characterized in that The coreless valve is closed by inserting a valve core into the coreless valve to close the coreless valve.

10. The method according to claim 7, characterized in that During the oil production operation, the adjustable rod pump adjusts the pumping depth of the adjustable rod pump by lifting and lowering the sucker rod according to the dynamic liquid level depth in the oil pipe above the full-bore air anchor.

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