Same-well injection and production equipment and methods

Abstract

This application provides a co-well injection and production oil production device and method, belonging to the field of oil and gas field development technology. The co-well injection and production oil production device includes a fixedly connected water injection sub and an oil production sub. The water injection sub is used to inject water into a connected water injection fracture through a check valve located on it during the water injection cycle. The oil production sub is used to extract oil from a connected oil production fracture through a check valve located on it during the oil production cycle. In the process of oil production using the above device, oil production is stopped during water injection and water injection is stopped during oil production. This alternating operation of water injection and oil production cycles avoids pressure differentials within the device, thereby significantly reducing the requirements for tubing equipment and thus lowering equipment costs while ensuring smooth oil production operations.

Description

Technical Field

[0001] This application relates to the field of oil and gas field development technology, and in particular to a same-well injection and production oil production device and method. Background Technology

[0002] With the large-scale development of oilfield resources, the quality of these resources is gradually deteriorating. A significant portion of newly discovered geological reserves are low-permeability, ultra-low-permeability, and tight oil layers. For these lower-quality oil layers, a combined injection and production method is typically employed to improve the utilization rate of individual wells.

[0003] Currently, the following method is used for simultaneous injection and production in a single well: a water injection string and a production string are installed in one wellbore. The water injection string is used to inject high-pressure water into the water-injection fractures in the oil reservoir to drive crude oil in the reservoir to seep into the production fractures. The production string is used to extract crude oil from the production fractures and transport the crude oil to the wellhead.

[0004] In the above method, the pressure in the water injection tubing is higher than that in the oil production tubing. During oil production, since the water injection tubing and the oil production tubing operate simultaneously, the pressure difference between them will be too large. In order to carry out oil production operations smoothly under such a large pressure difference, high-end tubing equipment is required. Due to the high requirements for tubing equipment, the equipment cost will be significantly increased. Summary of the Invention

[0005] This application provides a same-well injection and production oil production device and method to reduce the cost of oil production equipment. The technical solution is as follows:

[0006] In the first aspect, a co-well injection and production oil production device is provided. The device includes a water injection sub and an oil production sub that are fixedly connected. Check valves are respectively provided on the water injection sub and the oil production sub. The water injection sub is connected to the water injection fracture in the oil layer through the check valve located on it, and the oil production sub is connected to the oil production fracture in the oil layer through the check valve located on it.

[0007] A packer is installed between the water injection sub and the oil production sub; the packer is used to separate the first well section where the water injection fracture is located and the second well section where the oil production fracture is located.

[0008] During the water injection cycle in the oil production process, the water injection sub is used to inject water flowing into the water injection fracture connected to it through a check valve located on it; the oil production sub is used to prevent water flowing into the oil production sub from flowing into the oil production fracture through a check valve located on it.

[0009] During the oil production cycle, the oil production sub is also used to extract crude oil from the oil production fracture through the check valve located on it; the water injection sub is also used to prevent water from flowing from the water injection fracture to the water injection sub through the check valve located on it.

[0010] The same-well injection-production oil production device provided in this application includes a fixedly connected water injection sub and an oil production sub. The water injection sub is used to inject water into the connected water injection fracture through a check valve located on it during the water injection cycle. The oil production sub is used to extract oil from the connected oil production fracture through a check valve located on it during the oil production cycle. In the process of oil production using the above device, oil production is stopped during water injection, and water injection is stopped during oil production. This alternating operation of water injection and oil production cycles avoids pressure differentials within the device, thereby significantly reducing the requirements for tubing equipment and ultimately lowering equipment costs while ensuring smooth oil production operations.

[0011] Optionally, the check valve includes a ball cylinder, a ball seat, and a cross-shaped baffle. The first end of the ball cylinder is connected to the ball seat, and the second end of the ball cylinder is connected to the cross-shaped baffle. The ball cylinder includes a ball.

[0012] On the water injection short section, the ball seat is located inside the water injection short section, and the cross-shaped baffle is located outside the water injection short section. The water injection short section is connected to the check valve through the ball seat.

[0013] On the oil production sub, the cross-shaped baffle is located inside the oil production sub, and the ball seat is located outside the oil production sub. The oil production sub is connected to the check valve through the cross-shaped baffle.

[0014] Optionally, for the check valve on the water injection sub, during the water injection cycle, the ball seat on the check valve is used to transfer the water flowing into the water injection sub to the check valve;

[0015] The sphere is used to move from the position of the ball seat to the position of the cross-shaped baffle under the propulsion of water. The gap between the sphere and the cross-shaped baffle is used to transfer the water flowing into the water injection section to the water injection crack.

[0016] Optionally, for the check valve on the oil production sub, during the water injection cycle, the ball is used to move from the position of the cross-shaped baffle to the position of the ball seat under the push of water, preventing the water flowing into the oil production sub from flowing through the ball seat to the oil production fracture.

[0017] Optionally, for the check valve on the oil production sub, during the oil production cycle, the ball seat on the check valve is used to transfer crude oil flowing from the oil production fracture to the check valve;

[0018] The ball is used to move from the position of the ball seat to the position of the cross-shaped baffle under the push of crude oil. The gap between the ball and the cross-shaped baffle is used to transfer the crude oil flowing from the oil production fracture to the oil production sub.

[0019] Optionally, for the check valve on the water injection sub, during the oil production cycle, the ball is used to move from the position of the cross-shaped baffle to the position of the ball seat under the pressure in the water injection fracture, preventing water in the water injection fracture from flowing through the ball seat to the water injection sub.

[0020] Optionally, protectors are provided on the outer sides of the water injection sub and the oil production sub, respectively, to isolate the check valve from the inner wall of the well.

[0021] Optionally, there may be multiple water injection sub-sections and multiple oil production sub-sections.

[0022] Optionally, multiple water injection sub-sections and multiple oil production sub-sections are fixedly connected according to a preset rule, which is used to indicate the distribution of water injection fractures and oil production fractures.

[0023] In a second aspect, a method for producing oil in the same well is provided. This method is applied to the same well injection and production equipment provided by the first aspect or various optional implementations of the first aspect. The equipment includes a water injection sub and an oil production sub that are fixedly connected. Check valves are respectively provided on the water injection sub and the oil production sub. The water injection sub is connected to the water injection fracture in the oil layer through the check valve located thereon, and the oil production sub is connected to the oil production fracture in the oil layer through the check valve located thereon.

[0024] The method includes:

[0025] During the water injection cycle in the oil production process, water flowing into the water injection sub is injected into the water injection fracture connected to it through a check valve located on the water injection sub; and water flowing into the oil production sub is prevented from flowing into the oil production fracture through a check valve located on the oil production sub.

[0026] During the oil production cycle, crude oil is extracted from the production fracture through a check valve located on the production sub; and water is prevented from flowing from the water injection fracture to the water injection sub through a check valve located on the water injection sub.

[0027] Based on the implementation methods provided in the above aspects, this application can be further combined to provide more implementation methods. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1This is a schematic diagram of the structure of a same-well injection and production oil production device provided in an embodiment of this application;

[0030] Figure 2 This is a schematic diagram of the structure of a check valve provided in an embodiment of this application;

[0031] Figure 3 This is a schematic diagram of the structure of a water-filled short section provided in an embodiment of this application;

[0032] Figure 4 This is a schematic diagram of the structure of an oil production sub-section provided in an embodiment of this application;

[0033] Figure 5 This is a flowchart of a method for oil production through injection and production in the same well, provided in an embodiment of this application.

[0034] The reference numerals in the figure indicate:

[0035] 11 to 15 - fractures, 2 - water injection sub, 3 - oil production sub, 41 to 45 - packers.

[0036] 21-Spherical tube, 22-Spherical base, 23-Cross-shaped baffle, 24-Spherical body. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0038] In this application, the terms "first," "second," etc., are used to distinguish identical or similar items with essentially the same function. It should be understood that there is no logical or temporal dependency between "first," "second," and "nth," nor are there any restrictions on quantity or execution order.

[0039] In this application, the term "at least one" means one or more, and "multiple" means two or more.

[0040] It should be noted that the information (including but not limited to user device information, user personal information, etc.), data (including but not limited to data used for analysis, data stored, data displayed, etc.) and signals involved in this application are all authorized by the user or fully authorized by all parties, and the collection, use and processing of related data must comply with the relevant laws, regulations and standards of the relevant countries and regions.

[0041] The following is combined with Figures 1 to 4 This application will introduce the same-well injection and production oil production device provided in the embodiments.

[0042] Figure 1 This is a schematic diagram of the structure of a same-well injection and production oil production device provided in an embodiment of this application.

[0043] like Figure 1 As shown, the same-well injection-production oil recovery device is applied to a horizontal wellbore. Before applying this device, the horizontal wellbore is subjected to staged fracturing to create multiple fractures perpendicular to the horizontal wellbore in the oil layer, such as... Figure 1 Fractures 11-15 are among the fractures. These fractures include water injection fractures and oil production fractures. The water injection fractures are used to inject water into the oil reservoir to displace the crude oil in the reservoir and flow out through the oil production fractures.

[0044] Optionally, taking one of the aforementioned fractures as an example, this fracture can be designated as a water injection fracture, and the fractures adjacent to it can be designated as oil production fractures. For example, see... Figure 1 Fractures 12 and 14 are designated as water injection fractures, while fractures 11, 13, and 15 are designated as oil production fractures.

[0045] The method described above for identifying water injection fractures and oil production fractures from multiple fractures is merely an example. By designating fractures adjacent to water injection fractures as oil production fractures, the pressure generated by water injection can be effectively utilized, thereby improving crude oil extraction efficiency. Of course, relevant personnel can also determine water injection fractures and oil production fractures through other methods according to actual needs, and this application does not limit this approach.

[0046] The structure of the same-well injection and production oil production device provided in the embodiments of this application will be described below.

[0047] See Figure 1 The same-well injection and production unit includes a fixedly connected water injection section 2 and an oil production section 3. Check valves are installed on both sections. The water injection section 2 is connected to the water injection fracture in the oil layer via its check valve, and the oil production section 3 is connected to the oil production fracture in the oil layer via its check valve. For example, Figure 1 In the process, the water injection sub-section 2 is connected to the water injection fracture 12 in the oil layer through a check valve located on it, and the oil production sub-section 3 is connected to the oil production fracture 13 in the oil layer through a check valve located on it.

[0048] In this design, the fixedly connected water injection subsection 2 and oil production subsection 3 are implemented as a single tubing, which can be a thickened tubing, etc., and this application does not limit this to any particular type. A packer is installed between the water injection subsection 2 and the oil production subsection 3. The packer is located in the annular space between the tubing and the wellbore, and is used to separate the first well section where the water injection fracture is located and the second well section where the oil production fracture is located. For example, Figure 1In this design, packers 41 to 45 divide the horizontal well into five sections. The section between packers 41 and 42 is the second section containing the oil production fracture 11, and the section between packers 42 and 43 is the first section containing the water injection fracture 12. By using packers to separate the first section containing the water injection fracture from the second section containing the oil production fracture, water injected into the first section can be prevented from flowing into the second section containing the oil production fracture during water injection, and crude oil flowing into the second section containing the oil production fracture can be prevented from flowing into the first section containing the water injection fracture during oil production, thereby improving crude oil extraction efficiency.

[0049] The oil production process of the aforementioned same-well injection-production oil production unit includes a water injection cycle and an oil production cycle, which alternate. For example, the first 16 days of the oil production process are the water injection cycle, the next 16 days are the oil production cycle, and the following 16 days are the water injection cycle again.

[0050] During the water injection cycle in the oil production process, the water injection sub 2 is used to inject water flowing into the water injection fracture connected to it through the check valve located on it, and the oil production sub 3 is used to prevent water flowing into the oil production sub 3 from flowing into the oil production fracture through the check valve located on it.

[0051] Accordingly, during the aforementioned water injection cycle, the water injection equipment injects high-pressure water into the tubing. After the water in the tubing flows into the water injection sub, the check valve located on the water injection sub 2 discharges the water from the sub into the well section connected to it. This well section is the first well section where the water injection fracture is located. After the check valve discharges water into the first well section, the water is injected into the water injection fracture within the first well section, causing the water injected into the water injection fracture to displace the crude oil in the oil layer and flow out through the production fracture. Figure 1 As shown, after the check valve on the water injection section 2 injects water into the water injection fracture 12, the water flows to both sides of the water injection fracture 12 to apply pressure to the crude oil in the oil layer, causing the crude oil to flow in the direction of the oil production fractures 11 and 13.

[0052] During the aforementioned water injection cycle, after water flows into production subsection 3 from the tubing, a check valve located on production subsection 3 seals the passage between production subsection 3 and the well section where it is located. This prevents water flowing into production subsection 3 from passing through the check valve and entering the well section where it is located. This well section is the second well section where the production fracture is located. By sealing the passage between production subsection 3 and the second well section, the check valve prevents water from being injected into the production fracture in the second well section, thus avoiding simultaneous pressure exerted by the injected water on both the water injection fracture and the production fracture, facilitating the subsequent flow of crude oil from the production fracture. Furthermore, since a packer is installed between the first well section where the water injection fracture is located and the second well section where the production fracture is located, water flowing into the first well section cannot flow into the second well section. This similarly prevents simultaneous pressure exerted by the injected water on both the water injection fracture and the production fracture, facilitating the subsequent flow of crude oil from the production fracture and thus improving crude oil extraction efficiency.

[0053] During the oil production cycle, the oil production sub 3 is also used to extract crude oil from the oil production fracture through the check valve located on it, and the water injection sub 2 is also used to prevent water in the water injection fracture from flowing into the water injection sub 2 through the check valve located on it.

[0054] Accordingly, during the aforementioned oil production cycle, after the crude oil in the oil layer flows into the second well section where the oil production fracture is located through the oil production fracture under the displacement of water, the check valve located on the oil production sub 3 discharges the crude oil in the second well section connected to the oil production sub 3 into the oil production sub 3 so that the oil pumping equipment can extract the crude oil from the tubing.

[0055] During the same oil production cycle, after crude oil flows into production subsection 3, since production subsection 3 and water injection subsection 2 are interconnected, the crude oil in production subsection 3 will flow into water injection subsection 2. When the water from the aforementioned water injection fracture flows into the first well section where the water injection fracture is located, the check valve on water injection subsection 2 closes the channel between water injection subsection 2 and the first well section to prevent water flowing into the first well section from flowing back into water injection subsection 2. This prevents water from the water injection fracture from contaminating the crude oil in water injection subsection 2 and improves crude oil extraction efficiency.

[0056] Optionally, such as Figure 1 As shown, there are multiple water injection sub-sections 2 and multiple oil production sub-sections 3. Multiple water injection sub-sections 2 and multiple oil production sub-sections 3 can improve the utilization rate of oil wells and improve the development efficiency of crude oil.

[0057] Optionally, the aforementioned multiple water injection sub-units 2 and multiple oil production sub-units 3 are fixedly connected according to a preset rule. This preset rule is used to indicate the distribution of water injection fractures and oil production fractures, so that the water injection sub-units 2 are connected to the water injection fractures, and the oil production sub-units 3 are connected to the oil production fractures. This allows for water injection through some fixed fractures and oil production through other fixed fractures, and enables a coupled injection-production method where oil production is stopped during water injection and water injection is stopped during oil production, thereby improving crude oil extraction efficiency. For example, Figure 1 In this configuration, water injection fractures and oil production fractures are distributed alternately. Therefore, water injection sub-section 2 and oil production sub-section 3 are also distributed alternately, ensuring a one-to-one correspondence between water injection sub-section 2 and water injection fractures, and a one-to-one correspondence between oil production sub-section 3 and oil production fractures. The above... Figure 1 The distribution of multiple water injection subsections 2 and multiple oil production subsections 3 is merely an example. Optionally, the distribution of multiple water injection subsections 2 and multiple oil production subsections 3 may be such that a first number of fixedly connected water injection subsections 2 and a second number of fixedly connected oil production subsections 3 are distributed alternately, with the first number of fixedly connected water injection subsections 2 connected to the same water injection fracture and the second number of fixedly connected oil production subsections 3 connected to the same oil production fracture. Alternatively, they may be distributed according to reservoir requirements. This application does not limit this distribution.

[0058] Optionally, such as Figure 1 As shown, a bridge plug is provided on the aforementioned tubing. The bridge plug is used to fix the tubing to prevent it from moving in the wellbore, thereby preventing the water injection sub-section 2 from connecting with the oil production fracture or the oil production sub-section 3 from connecting with the water injection fracture, so that the aforementioned same-well injection and production oil production device can carry out oil production operations smoothly.

[0059] Optionally, such as Figure 1 As shown, the end of the aforementioned oil pipe is blocked to prevent water or crude oil flowing into the oil pipe from flowing out from its end.

[0060] The structure of the check valve in the above-mentioned well injection and production oil production device is described below.

[0061] Figure 2 This is a schematic diagram of a check valve provided in an embodiment of this application. See also... Figure 2 The check valve includes a ball cylinder 21, a ball seat 22, and a cross-shaped baffle 23. Figure 2In the diagram, the left side of the check valve is a left view, and the right side is a right view. The first end of the ball cylinder 21 is connected to the ball seat 22, and the second end is connected to the cross-shaped baffle 23. The ball cylinder 21 includes a ball 24 and is connected to the outside world through the ball seat 22 and the cross-shaped baffle 23. The ball 24 can be a solid steel ball, with a diameter smaller than the diameter of the ball cylinder 21 and a diameter greater than or equal to the diameter of the ball seat 22. The smaller diameter of the ball 24 compared to the ball cylinder 21 creates a gap between the ball 24 and the ball cylinder 21, allowing the liquid flowing through the check valve to pass through this gap and thus enabling the check valve to transfer liquid. The diameter of the ball 24 is greater than or equal to the diameter of the ball seat 22, so that the ball 24 can seal the ball seat 22, that is, seal the ball seat 22 to prevent the liquid flowing into the check valve from the position of the cross-shaped baffle 23 from flowing out from the position of the ball seat 22, ensuring that the check valve can only transmit liquid in one direction.

[0062] Both the ball seat 22 and the cross-shaped baffle 23 are used to transfer the liquid flowing through the check valve. The ball 24 is used to roll within the ball cylinder 21 under the pressure of the liquid flowing through the check valve. When the liquid flows into the check valve through the ball seat 22, the ball 24 is moved from the position of the ball seat 22 to the position of the cross-shaped baffle 23 under the pressure of the liquid. After the ball 24 moves to the position of the cross-shaped baffle 23, the cross-shaped baffle 23 blocks the ball 24, preventing it from rolling out of the ball cylinder 21. The gaps between the ball 24 and the ball cylinder 21, and between the ball 24 and the cross-shaped baffle 23, are used to transfer the liquid, allowing it to flow out through the gap between the ball 24 and the ball cylinder 21, and then through the gap (fan-shaped space) between the ball 24 and the cross-shaped baffle 23, and out of the ball cylinder 21. When liquid flows into the check valve through the cross-shaped baffle 23, the ball 24 is moved from the position of the cross-shaped baffle 23 to the position of the ball seat 22 under the push of the liquid. After the ball moves to the position of the ball seat 22, the ball seat 22 blocks the ball 24 to prevent the ball 24 from rolling out of the ball cylinder 21, and the ball 24 seals the ball seat 22 to prevent the liquid in the ball cylinder 21 from flowing out of the ball cylinder 21 through the ball seat 22.

[0063] The above embodiment is illustrated by taking the movement of the ball 24 driven by liquid as an example. Optionally, the ball 24 is used to move in the ball cylinder 21 under the pressure of a certain end of the ball cylinder 21. This application does not limit this.

[0064] The above content describes the structure of the check valve in the same-well injection and production oil production unit. The following section describes the structure of the water injection sub and the oil production sub in the same-well injection and production oil production unit, based on the above check valve structure.

[0065] Figure 3 This is a schematic diagram of the structure of a water-filled short section provided in an embodiment of this application. For example... Figure 3 As shown, the water injection section is implemented as a section of oil pipe, and multiple check valves are distributed on the pipe wall. The distribution of these multiple check valves can be uniformly distributed according to a preset interval, etc., and this application does not limit this.

[0066] On the water-filled short section, such as Figure 3 As shown, the ball of the check valve is positioned perpendicular to the pipe wall. The solid circle indicates the location of the ball seat, and the cross shape indicates the location of the cross-shaped baffle. Clearly, the ball seat of the check valve is located inside the water injection sub-section, and the cross-shaped baffle is located outside the water injection sub-section. The water injection sub-section is connected to the check valve via the ball seat. When liquid flows from the water injection sub-section to the well section where it is located, as described above, the ball seat on the check valve transfers the liquid from the water injection sub-section to the check valve. The ball, propelled by the liquid, moves from the ball seat to the cross-shaped baffle. When the ball reaches the cross-shaped baffle, it is blocked by the baffle, and the liquid flows out of the check valve and into the well section where the water injection sub-section is located through the gaps between the ball and the ball barrel, and between the ball and the cross-shaped baffle.

[0067] When fluid flows from the well section containing the water injection sub to the water injection sub, as described above, the cross-shaped baffle on the check valve transfers the fluid from the well section to the check valve. The ball, propelled by the fluid, moves from the position of the cross-shaped baffle to the position of the ball seat. Once the ball reaches the ball seat, it closes the seat, preventing fluid from flowing out of the check valve and thus avoiding fluid flowing into the water injection sub. Alternatively, when the pressure in the water injection sub is lower than the pressure in the water injection fracture, the ball, propelled by the pressure in the water injection fracture, moves from the position of the cross-shaped baffle to the position of the ball seat. Once the ball reaches the ball seat, it closes the seat, preventing fluid flowing out of the water injection fracture from flowing out of the check valve and thus avoiding fluid flowing into the water injection sub.

[0068] Optionally, such as Figure 3 As shown, a protector is installed on the outside of the water injection sub. The protector is used to isolate the check valve from the inner wall of the oil well, so as to prevent the check valve on the oil pipe from rubbing or bumping against the inner wall of the oil well when the oil pipe is being run into or pulled out of the oil well. This extends the service life of the oil pipe, reduces the wear rate of the oil pipe, and reduces the cost of the oil pipe.

[0069] Figure 4 This is a schematic diagram of the structure of an oil production sub-section provided in an embodiment of this application. For example... Figure 4As shown, the oil production sub is also implemented as a section of tubing, with multiple check valves distributed on the tubing wall. The distribution of these check valves can be uniform at predetermined intervals, etc., and this application does not limit this. The distribution of check valves on the oil production sub can be the same as or different from the distribution of check valves on the water injection sub; this application does not limit this.

[0070] On the oil production sub, such as Figure 4 As shown, the ball valve's cylinder is positioned perpendicular to the pipe wall. The solid circle indicates the location of the ball seat, and the cross shape indicates the location of the cross-shaped baffle. Clearly, the cross-shaped baffle is located inside the oil production sub, while the ball seat is located outside. The oil production sub is connected to the check valve via the cross-shaped baffle.

[0071] When fluid flows from the production sub to the well section where it is located, as described above, the cross-shaped baffle on the check valve transfers the fluid from the production sub to the check valve. The ball, propelled by the fluid, moves from the position of the cross-shaped baffle to the position of the ball seat. Once the ball reaches the ball seat, it seals the seat, preventing fluid from flowing out of the check valve and thus avoiding fluid flowing into the well section where the production sub is located. Conversely, when fluid flows from the well section where the production sub is located to the production sub, as described above, the ball seat on the check valve transfers the fluid from the well section to the check valve. The ball, propelled by the fluid, moves from the position of the ball seat to the position of the cross-shaped baffle. Once the ball reaches the cross-shaped baffle, it is blocked by the baffle, and the fluid flows out of the check valve and into the production sub through the gaps between the ball and the ball barrel, and between the ball and the cross-shaped baffle.

[0072] The above content describes the structure of the water injection sub and the oil production sub. As can be seen from the structural description of the same-well injection-production unit, the oil production process includes a water injection cycle and an oil production cycle, which alternate. The following section, in conjunction with the structure of the water injection sub and the oil production sub, explains the application of different subs in the water injection cycle and the oil production cycle.

[0073] First, the application of water injection sub-sections and oil production sub-sections in the water injection cycle will be explained.

[0074] During the water injection cycle, the pressure in the tubing, which consists of a water injection sub and a production sub, increases. Driven by this pressure, water in the tubing flows toward the check valve on the sub. The water injection sub is used to inject water into the water injection fracture it connects to through the check valve located on it. The production sub is used to prevent water from flowing into the production fracture it connects to through the check valve located on it.

[0075] Correspondingly, for the check valve on the water injection sub, the ball seat on the check valve is used to transfer the water flowing into the water injection sub to the check valve, and the ball on the check valve is used to move from the position of the ball seat to the position of the cross-shaped baffle under the push of the water. The gap between the ball and the cross-shaped baffle is used to transfer the water flowing into the water injection sub to the water injection fracture connected to the water injection sub, so that the water can apply pressure to the oil layer through the water injection fracture, thereby displacing the crude oil in the oil layer and moving it in the direction of the oil production fracture.

[0076] For the check valve on the oil production sub, the ball on the check valve is used to move from the position of the cross-shaped baffle to the position of the ball seat under the push of water, to prevent the water flowing into the oil production sub from flowing through the ball seat to the oil production fracture connected to the oil production sub, so as to avoid the oil production fracture and the water injection fracture being subjected to the pressure applied by water at the same time, and to avoid affecting the speed at which crude oil flows out of the oil production fracture, thereby avoiding reducing the crude oil extraction efficiency.

[0077] Secondly, the application of oil production sub-sections and water injection sub-sections in the oil production cycle is explained.

[0078] During the oil production cycle, the pressure inside the tubing decreases, and the crude oil in the reservoir flows into the well section where the production fracture is located through the production fracture under the displacement of water and the driving force of the pressure difference. The production sub is used to transfer the crude oil in the well section to the production sub through the check valve located on it. The water injection sub is used to prevent water from flowing into the water injection sub through the water injection fracture connected to it through the check valve located on it.

[0079] Accordingly, for the check valve on the oil production sub, the ball seat on the check valve is used to transfer the crude oil flowing from the oil production fracture to the check valve, and the ball on the check valve is used to move from the position of the ball seat to the position of the cross-shaped baffle under the push of the crude oil. The gap between the ball and the cross-shaped baffle is used to transfer the crude oil flowing from the oil production fracture to the oil production sub so that the crude oil can be subsequently extracted from the tubing.

[0080] For the check valve on the water injection sub, during the oil production cycle, the pressure in the tubing is lower than the pressure in the oil layer. The ball on the check valve is moved from the position of the cross-shaped baffle to the position of the ball seat under the pressure of water or water injection fracture, preventing water in the water injection fracture from flowing through the ball seat into the water injection sub. This avoids water flowing into the water injection fracture back into the water injection sub, thereby preventing water in the water injection fracture from contaminating the crude oil in the water injection sub and improving the crude oil extraction efficiency.

[0081] In summary, the same-well injection-production oil recovery device provided in this application includes a fixedly connected water injection sub and an oil recovery sub. The water injection sub is used to inject water into the water injection fracture connected to it through a check valve located on it during the water injection cycle. The oil recovery sub is used to extract oil from the oil recovery fracture connected to it through a check valve located on it during the oil recovery cycle. In the process of oil recovery using the above device, oil recovery is stopped during water injection and water injection is stopped during oil recovery. This alternating operation of water injection and oil recovery cycles avoids pressure differentials in the device, thereby significantly reducing the requirements for tubing equipment and thus reducing equipment costs while ensuring smooth oil recovery operations. Furthermore, the above-mentioned same-well injection-production oil recovery device is applied to horizontal wellbores, utilizing the advantages of long well sections and large well-controlled reserves in horizontal wells to expand the swept volume of water injection and improve crude oil recovery.

[0082] The above describes the same-well injection and production oil production device. The following describes the same-well injection and production oil production method provided in the embodiments of this application. This method is applied to the above-mentioned same-well injection and production oil production device.

[0083] Before implementing the same-well injection and production oil production method provided in this application embodiment, some preparatory work needs to be performed to ensure smooth oil production operations. This preparatory work includes: manually fracturing the horizontal wellbore in stages to create multiple water injection fractures and oil production fractures distributed according to a preset fracture distribution rule. Based on the distribution rule of the multiple water injection fractures and multiple oil production fractures, tubing conforming to this distribution rule is run into the horizontal wellbore so that the water injection sub-section in the tubing is connected to the water injection fracture, and the oil production sub-section in the tubing is connected to the oil production fracture.

[0084] After completing the above preparations, the same-well injection and production process begins. Figure 5 This is a flowchart of a same-well injection and production oil recovery method provided in an embodiment of this application. For example... Figure 5 As shown, taking an oil recovery process that includes one continuous water injection cycle and one oil recovery cycle as an example, the method includes the following steps:

[0085] 501. During the water injection cycle in the oil production process, the same-well injection and production unit injects water flowing into the water injection sub through a check valve located on the water injection sub and into the water injection fracture connected to it. The check valve located on the production sub prevents the water flowing into the production sub from flowing into the production fracture connected to it.

[0086] In this embodiment, during the water injection cycle, the pressure in the tubing increases. After water flows into the tubing, it flows towards the check valve on the tubing under pressure. The same-well injection-production device transmits water to the check valve via a ball seat located on the water injection sub. The ball in the check valve moves from the ball seat location to the cross-shaped baffle location under the drive of water or pressure. The same-well injection-production device transmits the water flowing into the water injection sub to the water injection fracture connected to the water injection sub through the gap between the ball and the cross-shaped baffle, allowing water to apply pressure to the oil layer through the water injection fracture, thereby displacing the crude oil in the oil layer and moving it towards the production fracture. The same-well injection-production device transmits water to the check valve via a cross-shaped baffle located on the production sub. The ball in the check valve moves from the cross-shaped baffle location to the ball seat location under the drive of water or pressure. The same-well injection and production unit uses a ball to seal the ball seat, preventing water flowing into the production sub from flowing through the ball seat to the production fracture connected to the production sub. This avoids the production fracture and the water injection fracture being simultaneously subjected to water pressure, thus preventing the rate at which crude oil flows out of the production fracture and avoiding a reduction in crude oil extraction efficiency.

[0087] 502. During the oil production cycle, the same well injection and production unit extracts crude oil from the production fracture through a check valve located on the production sub, and prevents water in the water injection fracture from flowing into the water injection sub through a check valve located on the water injection sub.

[0088] In this embodiment, during the oil production cycle, the pressure in the tubing decreases, making it lower than the pressure in the fracture. Driven by water displacement and pressure differential, crude oil in the reservoir flows through the production fracture into the well section where the fracture is located. The same-well injection-production unit transfers crude oil flowing from the production fracture to the check valve via a ball seat located on the production sub. The ball on the check valve, pushed by the pressure of the crude oil or the production fracture, moves from its position to the position of the cross-shaped baffle. The same-well injection-production unit then transfers crude oil flowing from the production fracture to the production sub through the gap between the ball and the cross-shaped baffle, so that the crude oil can be subsequently extracted from the tubing. The same-well injection-production unit also transfers water flowing from the water injection fracture to the check valve via a cross-shaped baffle located on the water injection sub. Under the pressure of water or water injection fracture, the ball on the check valve moves from the position of the cross-shaped baffle to the position of the ball seat. The well injection and production unit seals the ball seat through the ball, preventing water in the water injection fracture from flowing through the ball seat into the water injection sub-section. This prevents water flowing into the water injection fracture from flowing back into the water injection sub-section, thereby avoiding water contamination from the water injection fracture and its flow into the crude oil in the water injection sub-section, and improving the crude oil extraction efficiency.

[0089] 503. The same well injection and production unit will execute the next round of oil production process.

[0090] In the same-well injection and production oil production method provided in this application embodiment, water is injected into the water injection fracture connected to it through a check valve located on the water injection sub, and oil is extracted from the oil production fracture connected to it through a check valve located on the oil production sub. This achieves oil production through a single tubing, and allows for stopping oil production during water injection and stopping water injection during oil production. This alternating operation of water injection and oil production cycles avoids pressure differences in the equipment, thereby significantly reducing the requirements for tubing equipment while ensuring smooth oil production operations, and thus reducing equipment costs.

[0091] It should be noted that the apparatus provided in the above embodiments is only illustrated by the division of the above functional modules during oil extraction. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the apparatus can be divided into different functional modules to complete all or part of the functions described above. In addition, the apparatus and method embodiments provided in the above embodiments belong to the same concept, and their specific implementation process can be found in the method embodiments, which will not be repeated here.

[0092] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0093] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A single-well injection and production oil recovery device, characterized in that, The device includes a water injection sub and an oil production sub that are fixedly connected. Each of the water injection sub and the oil production sub is equipped with a check valve. The water injection sub is connected to the water injection fracture in the oil layer through the check valve located thereon, and the oil production sub is connected to the oil production fracture in the oil layer through the check valve located thereon. A packer is provided between the water injection sub and the oil production sub; the packer is used to separate the first well section where the water injection fracture is located and the second well section where the oil production fracture is located; During the water injection cycle in the oil production process, the water injection sub is used to inject water flowing into the water injection sub into the water injection fracture connected to it through the check valve located thereon; the oil production sub is used to prevent water flowing into the oil production sub from flowing into the oil production fracture through the check valve located thereon. During the oil production cycle, the oil production sub is also used to extract crude oil from the oil production fracture through the check valve located thereon; the water injection sub is also used to prevent water in the water injection fracture from flowing into the water injection sub through the check valve located thereon.

2. The apparatus according to claim 1, characterized in that, The check valve includes a ball cylinder, a ball seat, and a cross-shaped baffle. The first end of the ball cylinder is connected to the ball seat, and the second end of the ball cylinder is connected to the cross-shaped baffle. The ball cylinder contains a ball. On the water injection short section, the ball seat is located inside the water injection short section, the cross-shaped baffle is located outside the water injection short section, and the water injection short section is connected to the check valve through the ball seat; On the oil production sub, the cross-shaped baffle is located inside the oil production sub, and the ball seat is located outside the oil production sub. The oil production sub is connected to the check valve through the cross-shaped baffle.

3. The apparatus according to claim 2, characterized in that, For the check valve on the water injection section, during the water injection cycle, the ball seat on the check valve is used to transfer the water flowing into the water injection section to the check valve; The sphere is used to move from the position of the ball seat to the position of the cross-shaped baffle under the propulsion of water, and the gap between the sphere and the cross-shaped baffle is used to transfer the water flowing into the water injection section to the water injection crack.

4. The apparatus according to claim 2, characterized in that, For the check valve on the oil production sub, during the water injection cycle, the ball is used to move from the position of the cross-shaped baffle to the position of the ball seat under the push of water, preventing water flowing into the oil production sub from flowing through the ball seat to the oil production fracture.

5. The apparatus according to claim 2, characterized in that, For the check valve on the oil production sub, during the oil production cycle, the ball seat on the check valve is used to transfer crude oil flowing from the oil production fracture to the check valve; The ball is used to move from the position of the ball seat to the position of the cross-shaped baffle under the push of crude oil, and the gap between the ball and the cross-shaped baffle is used to transfer the crude oil flowing from the oil production fracture to the oil production sub.

6. The apparatus according to claim 2, characterized in that, For the check valve on the water injection sub, during the oil production cycle, the ball is used to move from the position of the cross-shaped baffle to the position of the ball seat under the pressure in the water injection fracture, preventing water in the water injection fracture from flowing through the ball seat to the water injection sub.

7. The apparatus according to claim 1, characterized in that, Protectors are provided on the outer sides of the water injection sub and the oil production sub, respectively, and the protectors are used to isolate the check valve from the inner wall of the oil well.

8. The apparatus according to claim 1, characterized in that, There are multiple water injection sub-sections and multiple oil production sub-sections.

9. The apparatus according to claim 8, characterized in that, Multiple water injection sub-sections and multiple oil production sub-sections are fixedly connected according to a preset rule, which is used to indicate the distribution of the water injection fractures and the oil production fractures.

10. A method for oil production through injection and production in a single well, characterized in that, An oil production device for injection and production in the same well, as described in any one of claims 1 to 9, comprises a water injection sub and an oil production sub that are fixedly connected. Each of the water injection sub and the oil production sub is provided with a check valve. The water injection sub is connected to a water injection fracture in the oil layer through the check valve located thereon, and the oil production sub is connected to an oil production fracture in the oil layer through the check valve located thereon. The method includes: During the water injection cycle in the oil production process, water flowing into the water injection sub is injected into the water injection fracture connected to it through the check valve located on the water injection sub; and water flowing into the oil production sub is prevented from flowing into the oil production fracture through the check valve located on the oil production sub; during the oil production cycle in the oil production process, crude oil is extracted from the oil production fracture through the check valve located on the oil production sub; and water flowing into the water injection sub is prevented from flowing into the water injection sub through the check valve located on the water injection sub.

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