Device for the section-by-section displacement pumping of oil in horizontal boreholes

Abstract

A device for the section-by-section displacement conveyance of oil in horizontal boreholes, characterized in that it comprises a borehole pipe of the horizontal borehole, a conveying pipe running through the borehole pipe, and a separating device for injection and conveyance arranged between the borehole pipe and the conveying pipe; wherein the horizontal borehole is divided along its axial direction into a water injection section and a production section, several water injection holes are formed in the pipe wall of the borehole pipe in the water injection section, and several oil production holes are formed in the pipe wall of the borehole pipe in the production section; The injection and conveying separation device comprises a first packer, a second packer, and at least one flow tube, wherein the first packer and the second packer are spaced apart along the axial direction of the horizontal borehole, and the flow tube is positioned between the first packer and the second packer; and An oil collection opening is formed in the pipe wall of the delivery pipe, which extends inside the production section, wherein the oil collection opening serves to introduce the crude oil extracted from the production section into the delivery pipe, and the delivery pipe serves to transport the introduced crude oil to the earth's surface.

Description

Technical area

[0001] The present utility model relates to the technical field of petroleum production, in particular a device for the section-by-section displacement production of oil in horizontal boreholes. State of the art

[0002] Horizontal wells, an important extraction method for increasing oil production rates, are characterized by a large oil surface area and a high single-well production rate. Particularly in the development of low-permeability oil formations, the development model currently employed is primarily one of water injection through vertical wells followed by oil production through horizontal wells, which can achieve a relatively high production rate in the initial stages. However, as development progresses, the disadvantages of this model gradually become apparent in low-permeability oil formations: the injected water tends to rapidly penetrate along the high-permeability zones of the oil formations. Furthermore, under the long-term flushing effect of the water injection, preferential flow channels can easily form within the oil formations.Once the preferred channels have formed, the water content of the horizontal boreholes rises rapidly, and the oil production rate drops drastically. Subsequently injected water circulates in large quantities along the preferred channels, resulting in ineffective water injection. However, highly saturated oil remains in the areas not reached by the water, severely limiting the development efficiency of the horizontal boreholes and thus leading to resource waste and a decrease in development effectiveness.

[0003] The traditional injection and production system using vertical and horizontal boreholes inherently has shortcomings in its overall injection and production model. The contact area between the formation rock surrounding the vertical boreholes and the borehole shafts is small, making water injection difficult. Furthermore, the effectiveness of the water containment system after water enters the horizontal boreholes is insufficient, severely limiting the efficiency of water-driven development.

[0004] Although some injection and production systems exist in the prior art, they exhibit problems such as poor separation and sealing performance, unclear flow paths, and the lack of effective backflow prevention and centering structures. Furthermore, they are unable to meet the specific requirements of the model of water injection through vertical boreholes and oil production through horizontal boreholes in low-permeability oil formations. It is not possible to locate the position of the water-filled section of the horizontal borehole using subsurface monitoring technology. Likewise, it is not possible to implement an injection and production changeover in the form of "decommissioning the water injection boreholes, converting the water-filled section into a water injection section, and production from the remaining sections."It is not possible to change the direction of water injection to mobilize the remaining oil in areas of low water flooding, meaning that the development difficulties caused by the preferred flow channels cannot be resolved. Therefore, there is an urgent need to develop a device for the section-by-section displacement production of oil in horizontal boreholes that ensures a rational structure, reliable sealing, directed flow, and stable oil production, while also meeting the requirements for flexible switching between injection and production sections in low-permeability oil formations, thus overcoming the shortcomings of the prior art. Content of the utility model

[0005] The purpose of this utility model is to provide a device for the section-by-section displacement extraction of oil in horizontal boreholes. This device is intended to achieve a section-by-section separation of injection and extraction, as well as directed flow of the injected water. Simultaneously, it ensures the stability of the production pipe and prevents backflow during oil production. Furthermore, it is designed to allow for flexible switching between water-filled sections and oil production sections, enabling the direction of water injection to be changed, and thus improving the efficiency of oil displacement extraction and the oil production rate.

[0006] To achieve the above-mentioned objective, the present utility model offers a device for the section-by-section displacement conveyance of oil in horizontal boreholes, comprising a borehole pipe of the horizontal borehole, a conveying pipe running through the borehole pipe, and a separating device for injection and conveyance arranged between the borehole pipe and the conveying pipe; wherein the horizontal borehole is divided along its axial direction into a water injection section and a production section, several water injection holes are formed in the pipe wall of the borehole pipe in the water injection section, and several oil production holes are formed in the pipe wall of the borehole pipe in the production section; The injection and conveying separation device comprises a first packer, a second packer, and at least one flow tube, wherein the first packer and the second packer are spaced apart along the axial direction of the horizontal borehole, and the flow tube is positioned between the first packer and the second packer; and An oil collection opening is formed in the pipe wall of the delivery pipe, which extends inside the production section, wherein the oil collection opening serves to introduce the crude oil extracted from the production section into the delivery pipe, and the delivery pipe serves to transport the introduced crude oil to the earth's surface.

[0007] Preferably, the first packer and the second packer are arranged symmetrically between the borehole pipe and the production pipe in a sealing manner, wherein the first packer is located on the side of the production section that is closer to the borehole head, the second packer is located on the side of the production section that is closer to the water injection section, and the first and the second packer serve to insulate the annular space of the production section.

[0008] The flow pipe is arranged parallel to the axis of the delivery pipe on one side of the delivery pipe, with one end of the flow pipe sealingly penetrating the first packer and communicating with the annular space of the water supply section located on the side of the first packer facing the wellhead, the other end of the flow pipe sealingly penetrating the second packer and communicating with the annular space of the water injection section, and the flow pipe serves to direct the injected water in the annular space of the water supply section into the annular space of the water injection section.

[0009] Preferably, the device further comprises a metering valve arranged at the borehole head, wherein the inlet of the metering valve is connected to the surface water injection pipeline network, the outlet of the metering valve is connected to the annular space of the water supply section, and the metering valve serves to control the supply, shut-off and flow control of the injected water.

[0010] Preferably, the number of flow pipes is one or two, wherein, in the case of two flow pipes, the two flow pipes are arranged symmetrically to the central axis of the conveying pipe on both sides of the conveying pipe, and both ends of the flow pipes are connected to the annular space of the water conveying section and the annular space of the water injection section, respectively.

[0011] Preferably, at least one centering device is arranged in the lower end of the borehole pipe, wherein the centering device is pushed onto the outer wall of the production pipe, the outer circumference of the centering device rests against the inner wall of the borehole pipe, and the centering device serves to center the production pipe along its axial direction.

[0012] Preferably, a foot valve is arranged at the lower end of the production pipe, wherein the foot valve is located in the sealed space between the lower end of the well pipe and the lowest centering device, the flow direction of the foot valve is in the direction from the production section to the earth's surface, and the foot valve serves to prevent the crude oil in the production pipe from flowing back into the well pipe.

[0013] Accordingly, the present utility model uses the aforementioned device for the section-by-section displacement conveyance of oil in horizontal boreholes, which has the following technical effects: (1) The present application achieves, through the symmetrical sealing arrangement of the first packer and the second packer, an effective isolation of the annular space of the production section from the annular space of the water conveying section and the water injection section. This completely solves the problem of cross-flow between the sections and ensures that injected water and crude oil each flow along predetermined paths. (2) The present application connects the annular space of the water-carrying section to the water-injection section via the flow tube, so that the injected water enters the water-injection section along the predetermined path. This avoids the waste of injected water and improves the directivity of the water-driven displacement pumping. In particular, the device is suitable for the requirement of converting a water-carrying section in a low-permeability oil formation into a water-injection section. It changes the direction of water injection, effectively mobilizes the remaining oil in the low-water-flooding areas, and alleviates the problem of preferred flow channels. (3) The present application increases the contact area with the oil layer by means of sectional injection and conveyance. This significantly reduces the water injection pressure and solves the problem of the difficulty of water injection through vertical boreholes.

[0014] The technical solution of the present utility model is described in more detail below with reference to the drawings and exemplary embodiments. Description of the attached drawings Fig. Figure 1 is a schematic structural view of a device for the section-by-section displacement conveyance of oil in horizontal boreholes according to the present utility model. Reference symbol list:

[0015] 1-Borehole pipe; 2-Conveyor pipe; 3-First packer; 4-Second packer; 5-Flow pipe; 6-Water injection section; 7-Production section; 8-Water injection hole; 9-Oil delivery hole; 10-Oil collection port; 11-Metering valve; 12-Centerer; 13-Foot valve; and 14-Water conveying section. Examples of implementation

[0016] The technical solution of the present utility model will be further explained below with reference to the drawings and examples of embodiment.

[0017] Unless otherwise defined, the technical or scientific terms used in this utility model shall have the usual meanings understood by a person skilled in the art in the field of this utility model. Terms such as "first," "second," and similar terms used in this utility model do not denote any order, quantity, or importance, but serve only to distinguish between different components. Terms such as "comprising" or "containing" and similar terms mean that the element or object preceding the word includes the elements or objects listed after the word, as well as their equivalents, but does not exclude any other elements or objects. Terms such as "connected" or "linked" and similar terms are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.Terms like "above," "below," "left," "right," and similar terms are used only to indicate relative positions. If the absolute position of the described object changes, the relative position can be changed accordingly.

[0018] As in Fig. As shown in Figure 1, the device for the section-by-section displacement conveyance of oil in horizontal boreholes comprises a borehole pipe 1 of the horizontal borehole, a conveying pipe 2 running through the borehole pipe 1 and a separating device for injection and conveyance arranged between the borehole pipe 1 and the conveying pipe 2.

[0019] The horizontal well is divided along its axial direction into a water injection section 6 and a production section 7. Several water injection holes 8 are formed in the casing wall of the well pipe 1 in the water injection section 6. The water injection holes 8 are evenly distributed along the circumference of the well pipe 1 and serve to introduce the injected water into the oil formation area. Several oil recovery holes 9 are formed in the casing wall of the well pipe 1 in the production section 7, which serve to collect the crude oil displaced from the oil formation.

[0020] The injection and production separation device comprises a first packer 3, a second packer 4, and at least one flow pipe 5. The first packer 3 and the second packer 4 are spaced apart along the axial direction of the horizontal borehole and are both designed as hydraulic expansion packers. The first packer 3 and the second packer 4 are arranged symmetrically between the borehole casing 1 and the production casing 2, sealing against each other. The first packer 3 is located on the side of the production section 7 that is closer to the borehole head. The second packer 4 is located on the side of the production section 7 that is closer to the water injection section 6. The expanding seal of the two packers isolates the annular space of the production section 7 from other areas and prevents cross-flow.

[0021] The flow pipe 5 is arranged parallel to the axis of the delivery pipe 2 on one side of the delivery pipe 2 and is made of a high-strength, corrosion-resistant steel pipe. One end of the flow pipe 5 penetrates the first packer 3, sealing it, and communicates with the annular space of the water supply section 14, which is located on the side of the first packer 3 facing the wellhead. The other end of the flow pipe 5 penetrates the second packer 4, sealing it, and communicates with the annular space of the water injection section 6. It serves to direct the injected water located in the annular space of the water supply section 14 into the annular space of the water injection section 6, thus ensuring precise penetration of the injected water into the water injection section 6.

[0022] The number of flow pipes 5 is one or two. With two flow pipes 5, the two flow pipes 5 are arranged symmetrically to the central axis of the delivery pipe 2 on both sides of the delivery pipe 2. Both ends of the flow pipes 5 are connected to the annular space of the water supply section 14 and the annular space of the water injection section 6, respectively, thereby improving the efficiency of the water supply system.

[0023] Oil collection openings 10 are formed in the pipe wall of the production pipe 2, which extends inside the production section 7. The oil collection openings 10 are designed as elongated holes and are evenly distributed along the circumference of the production pipe 2. They serve to introduce the crude oil extracted from the production section 7 into the production pipe 2. The end of the production pipe 2, which extends away from the wellhead, reaches the end of the well casing 1 and serves to transport the introduced crude oil to the surface.

[0024] A centering element 12 is also arranged at the lower end of the borehole casing 1 and is slid onto the outer wall of the production pipe 2. The outer circumference of the centering element 12 rests against the inner wall of the borehole casing 1. It serves to center the production pipe 2 along its axial direction, to prevent eccentric wear and bending of the production pipe 2, and thus to ensure the stability of oil production.

[0025] A foot valve 13, designed as a one-way ball valve, is located at the lower end of the production pipe 2. It is situated in the sealed space between the lower end of the well casing 1 and the centering device 12. The flow direction of the foot valve 13 is from the production section 7 to the surface. It serves to prevent backflow of crude oil in the production pipe 2 into the well casing 1 and to ensure oil production efficiency.

[0026] The device further comprises a metering valve 11 arranged at the borehole head, which is designed as an electromagnetic flow control valve. The inlet of the metering valve 11 is connected to the surface water injection pipeline network, and the outlet is connected to the annular space of the water supply section 14. It serves to control the supply, shut-off, and flow regulation of the injected water, thus enabling demand-based water injection. Operating principle:

[0027] Equipment Installation: After determining the position of the water-filled section of the horizontal borehole using subsurface monitoring techniques, the original vertical water injection boreholes are shut down. The water-filled section is designated as water injection section 6, and the remaining non-water-filled sections as production section 7. After assembling the delivery pipe 2, first packer 3, second packer 4, flow pipe 5, centering device 12, and foot valve 13, the entire assembly is lowered into the borehole casing 1 of the horizontal borehole. Hydraulic control expands and seals the first packer 3 and second packer 4, isolating the annular space of production section 7 from other areas.

[0028] Water injection displacement: The injected water is transported via the aboveground water injection pipeline network, and the metering valve 11 is opened and set to a predetermined flow rate. The injected water enters the annular space of the water conveying section 14, flows through the flow pipe 5 into the annular space of the water injection section 6, and then passes through the water injection holes 8 into the oil formation area to displace the crude oil.

[0029] Crude oil collection: The displaced crude oil enters the annular space of the production section 7 through the oil production holes 9 and flows through the oil collection openings 10 on the production pipe 2 into the interior of the production pipe 2.

[0030] Crude oil transport: The crude oil in the delivery pipe 2 is transported upwards under the influence of the pressure differential. The foot valve 13 prevents the crude oil from flowing back, so that the crude oil is finally conveyed to the aboveground oil collection system.

[0031] Finally, it should be noted that the foregoing embodiments serve only to illustrate, and not to limit, the technical solution of the present utility model. Although the present utility model has been described in detail with reference to preferred embodiments, those skilled in the art understand that they may modify the technical solution of the present utility model or replace it with equivalent alternatives without the modified technical solution departing from the spirit and scope of the technical solution of the present utility model.

Claims

[1] A device for the section-by-section displacement pumping of oil in horizontal boreholes, characterized by , comprising a borehole casing of the horizontal borehole, a conveying pipe running through the borehole casing, and a separating device for injection and conveying arranged between the borehole casing and the conveying pipe; wherein the horizontal borehole is divided along its axial direction into a water injection section and a production section, several water injection holes are formed in the pipe wall of the borehole pipe in the water injection section, and several oil production holes are formed in the pipe wall of the borehole pipe in the production section; The injection and conveying separation device comprises a first packer, a second packer, and at least one flow tube, wherein the first packer and the second packer are spaced apart along the axial direction of the horizontal borehole, and the flow tube is positioned between the first packer and the second packer; and An oil collection opening is formed in the pipe wall of the delivery pipe, which extends inside the production section, wherein the oil collection opening serves to introduce the crude oil extracted from the production section into the delivery pipe, and the delivery pipe serves to transport the introduced crude oil to the earth's surface. [2] The device for the section-by-section displacement conveyance of oil in horizontal boreholes according to claim 1, characterized by, that the first packer and the second packer are arranged symmetrically between the borehole pipe and the production pipe, with the first packer being located on the side of the production section closer to the borehole head, the second packer being located on the side of the production section closer to the water injection section, and the first and second packers serving to insulate the annular space of the production section;and that the flow tube is arranged parallel to the axis of the delivery pipe on one side of the delivery pipe, wherein one end of the flow tube seals through the first packer and communicates with the annular space of the water supply section located on the side of the first packer facing the wellhead, the other end of the flow tube seals through the second packer and communicates with the annular space of the water injection section, and the flow tube serves to direct the injected water in the annular space of the water supply section into the annular space of the water injection section. [3] The device for the section-by-section displacement conveyance of oil in horizontal boreholes according to claim 2, characterized by, that it further comprises a metering valve arranged at the borehole head, wherein the inlet of the metering valve is connected to the surface water injection pipeline network, the outlet of the metering valve is connected to the annular space of the water supply section, and the metering valve serves to control the supply, shut-off and flow control of the injected water. [4] The device for the section-by-section displacement conveyance of oil in horizontal boreholes according to claim 3, characterized by that the number of flow pipes is one or two, wherein, in the case of two flow pipes, the two flow pipes are arranged symmetrically to the central axis of the conveying pipe on both sides of the conveying pipe, and both ends of the flow pipes are connected to the annular space of the water conveying section and the annular space of the water injection section, respectively. [5] The device for the section-by-section displacement conveyance of oil in horizontal boreholes according to claim 4, characterized by , that at least one centering device is arranged in the lower end of the borehole pipe, wherein the centering device is pushed onto the outer wall of the production pipe, the outer circumference of the centering device rests against the inner wall of the borehole pipe, and the centering device serves to center the production pipe along its axial direction. [6] The device for the section-by-section displacement conveyance of oil in horizontal boreholes according to claim 5, characterized by, that a foot valve is arranged at the lower end of the production pipe, wherein the foot valve is located in the sealed space between the lower end of the well pipe and the lowest centering device, the flow direction of the foot valve is in the direction from the production section to the earth's surface, and the foot valve serves to prevent backflow of the crude oil in the production pipe into the well pipe.

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