SAGD steam injection well integrated device of offshore oilfield

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By designing an offshore oilfield SAGD steam injection well integrated device that combines SAGD steam injection well cyclic preheating and continuous injection integrated process strings and downhole safety control systems, the problem of the lack of downhole safety control in the existing technology is solved and achieved Efficient heavy oil extraction and safe operations in offshore oil fields.

CN119333087APending Publication Date: 2025-01-21CNOOC ENERGY TECHNOLOGY & SERVICES LTD

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Patent Information

Application Number: CN202411798491.9
Authority / Receiving Office: CN · China
Patent Type: Applications(China)
Current Assignee / Owner
Filing Date: 2024-12-09
Publication Date: 2025-01-21

AI Technical Summary

Technical Problem

The existing SAGD technology lacks underground safety control in the application of land oil fields, resulting in complex operation of column replacement, heat loss and safety hazards, and cannot be directly applied to offshore oil fields.

Method used

Design an integrated device for SAGD steam injection wells in offshore oil fields, which combines SAGD steam injection well cyclic preheating and continuous injection integrated process strings and downhole safety control systems, including insulated casings, large insulated oil pipes, and dual-channel components. and downhole safety control systems such as high temperature exhaust valves, high temperature downhole packers, high temperature downhole safety valves and high temperature downhole check valves.

Benefits of technology

The SAGD steam injection well can be operated without changing pipe strings during the cycle preheating and production stages, avoiding waste of heat energy, reducing operating costs and construction periods, meeting the safety requirements of offshore oil fields, and ensuring the safety and efficiency of thermal recovery operations.

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Abstract

The invention discloses an SAGD steam injection well integrated device of an offshore oilfield. The SAGD steam injection well integrated device comprises an SAGD steam injection well circulating preheating and continuous injection integrated process pipe column and an underground safety control system. The SAGD steam injection well circulating preheating and continuous injection integrated process pipe column comprises a heat insulation sleeve, the upper end of the heat insulation sleeve is connected with a sleeve hanger, the lower end of the heat insulation sleeve is connected with a large heat insulation oil pipe, and the lower end of the large heat insulation oil pipe is externally connected with a double-channel assembly; the double-channel assembly is internally connected with a small heat-insulation oil pipe, and the upper end of the small heat-insulation oil pipe is connected with an oil pipe hanger. The lower portion of the double-channel assembly is connected with the large oil pipe and the small oil pipe, the large oil pipe is communicated with the heat insulation sleeve and the annular space between the large heat insulation oil pipe and the small heat insulation oil pipe through the double-channel assembly, and the small oil pipe is communicated with the small heat insulation oil pipe through the double-channel assembly. Circulating preheating and continuous injection of the SAGD steam injection well are integrated, the underground safety control function is combined, efficient exploitation of thickened oil is promoted, and safety of thermal recovery operation is guaranteed.

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Description

Technical Field

[0001] The invention relates to the technical field of offshore heavy oil thermal recovery, and in particular to a SAGD steam injection well integrated device for an offshore oil field. Background Art

[0002] Among the world's oil and gas resources, heavy oil fields have great potential. The characteristics of heavy oil are high content of colloid and asphaltene, resulting in high viscosity, but its viscosity is extremely sensitive to temperature. The increase in temperature will cause the viscosity of heavy oil to drop sharply. It is an important topic in the petroleum industry to use various economical and efficient heavy oil thermal recovery technologies to maximize the recovery of heavy oil and high-condensate oil. Steam-assisted gravity drive (SAGD) technology is one of the key technologies for heavy oil recovery. The key process is that in the circulation preheating stage and the production stage, two different wellbore process strings are used in steam injection wells and production wells to respectively realize the functions of circulation preheating, steam injection and crude oil lifting.

[0003] At present, SAGD technology is mostly used in onshore oil fields. Onshore oil fields mainly apply SAGD technology to double horizontal wells and horizontal wells and vertical well groups. The steam injection wellbore tubing mostly consists of two trips of tubing in the preheating stage and the production stage, and there is no downhole safety control in the wellbore tubing structure. There are hidden dangers such as complicated tubing replacement operations, heat loss at the bottom of the well, and lack of downhole safety control during operations.

[0004] The existing SAGD wellbore technology for onshore oil fields cannot meet the safety requirements of downhole safety control and cannot be directly applied to offshore oil fields. Therefore, it is urgent to develop a SAGD wellbore technology that meets the requirements of offshore oil fields. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a SAGD steam injection well integrated device for an offshore oil field.

[0006] The present invention is achieved by adopting the following technical solutions.

[0007] A SAGD steam injection well integrated device for an offshore oil field comprises a SAGD steam injection well circulation preheating and continuous injection integrated process string and a downhole safety control system; the SAGD steam injection well circulation preheating and continuous injection integrated process string comprises an insulating sleeve, the upper end of the insulating sleeve is connected to a sleeve hanger, the lower end of the insulating sleeve is connected to a large insulating oil pipe, and the lower end of the large insulating oil pipe is connected to the outside of a dual-channel component; the dual-channel component is connected to a small insulating oil pipe, and the upper end of the small insulating oil pipe is connected to the oil pipe hanger; the lower part of the dual-channel component is respectively connected to a large oil pipe and a small oil pipe, the large oil pipe is connected through the annulus between the dual-channel component and the insulating sleeve, the large insulating oil pipe and the small insulating oil pipe, and the small oil pipe is connected to the small insulating oil pipe through the dual-channel component.

[0008] Furthermore, the dual-channel component is divided into three parts, namely, upper, middle and lower parts, along the axial direction. The upper part of the dual-channel component forms a through bridge channel, the lower part of the dual-channel component forms through outlet channel one and outlet channel two, and the middle part of the dual-channel component forms a connecting cavity, which connects the bridge channel and outlet channel one, and outlet channel one is connected to a large oil pipe; an oil pipe channel is also formed in the center of the dual-channel component along its axial direction, which connects the small insulated oil pipe and outlet channel two, and outlet channel two is connected to the small oil pipe.

[0009] Furthermore, the downhole safety control system includes a high-temperature exhaust valve, which is connected to a high-temperature downhole packer, and the high-temperature downhole packer is connected to a large insulated oil pipe to seal the annular space between the large insulated oil pipe and the production casing.

[0010] Furthermore, the downhole safety control system includes a high-temperature downhole safety valve, which is arranged inside the dual-channel component to seal the space inside the second pipe of the outlet channel inside the dual-channel component.

[0011] Furthermore, the downhole safety control system includes a high-temperature downhole check valve, which is connected to the large oil pipe to seal the inner space of the large oil pipe.

[0012] Furthermore, the lower end of the large oil pipe is connected to the large incline.

[0013] Furthermore, the lower end of the small oil pipe is connected to the small guide bevel.

[0014] This application has the following beneficial effects.

[0015] The present invention combines the SAGD steam injection well circulation preheating and continuous injection integration with the underground safety control function, which can realize the SAGD steam injection well operation without changing the pipe string during the circulation preheating and production stages, avoiding the waste of heat energy caused by changing the pipe string during the SAGD preheating and production stages, reducing the operation cost and construction period, and promoting the efficient recovery of heavy oil. At the same time, the present invention meets the offshore safety requirements, designs a safety control system underground, can ensure the safety of thermal recovery operations and provide technical support for the optimization of later process solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the present invention;

[0017] Figure 2 This is a diagram of the outer pipe column being lowered into the present invention;

[0018] Figure 3 This is a diagram of the inner pipe column being lowered into the present invention.

[0019] Among them, A-1: tubing hanger, A-2: production casing, A-3: casing hanger, A-4: small insulated tubing, A-5: insulated casing, A-6: large insulated tubing, A-7: dual-channel assembly, A-8: large tubing, A-9: small tubing, A-10: small guide angle, A-11: large guide angle;

[0020] B-1: hydraulic control pipeline, B-2: high temperature exhaust valve, B-3: high temperature downhole packer, B-4: high temperature downhole safety valve, B-5: high temperature downhole check valve;

[0021] C-1: bridge channel, C-2: oil pipe channel, C-3: outlet channel one, C-4: outlet channel two, C-5: connecting cavity. DETAILED DESCRIPTION

[0022] The present patent application is further described below in conjunction with embodiments.

[0023] like Figure 1-3 As shown, an integrated SAGD steam injection well device for an offshore oil field includes a SAGD steam injection well circulation preheating and continuous injection integrated process string and a downhole safety control system.

[0024] The SAGD steam injection well circulation preheating and continuous injection integrated process string includes a tubing hanger A-1, a casing hanger A-3, a small insulated tubing A-4, an insulated casing A-5, a large insulated tubing A-6, a dual-channel assembly A-7, a large tubing A-8, a small tubing A-9, a large guide inclination A-11, and a small guide inclination A-10.

[0025] Among them, the upper part of the insulating sleeve A-5 is connected to the sleeve hanger A-3, and the lower part is connected to the large insulating oil pipe A-6; the lower part of the large insulating oil pipe A-6 is connected to the outside of the dual-channel component A-7; the inside of the dual-channel component A-7 is connected to the small insulating oil pipe A-4, the upper part of the small insulating oil pipe A-4 is connected to the oil pipe hanger A-1, and the lower part of the dual-channel component A-7 is connected to the large oil pipe A-8 and the small oil pipe A-9; the lower part of the large oil pipe A-8 is connected to the large guide angle A-11; the lower part of the small oil pipe A-9 is connected to the small guide angle A-10.

[0026] The dual-channel component A-7 is divided into three parts along the axial direction, namely, upper, middle and lower parts. The upper part of the dual-channel component A-7 forms a through bridge channel C-1, the lower part of the dual-channel component A-7 forms through outlet channel 1 C-3 and outlet channel 2 C-4, the middle part of the dual-channel component A-7 forms a connecting cavity C-5, the connecting cavity C-5 connects the bridge channel C-1 and outlet channel 1 C-3, and outlet channel 1 C-3 is connected to the large oil pipe A-8; an oil pipe channel C-2 is also formed in the center of the dual-channel component A-7 along its axial direction, the oil pipe channel C-2 is arranged in the upper and middle parts of the dual-channel component A-7, the oil pipe channel C-2 connects the small insulated oil pipe A-4 and outlet channel 2 C-4, and outlet channel 2 C-4 is connected to the small oil pipe A-9.

[0027] Thus, the device of the present application forms two fluid channels: Channel 1 is composed of the annulus of the insulating sleeve A-5, the large insulating oil pipe A-6 and the small insulating oil pipe A-4, the bridge channel C-1, the connecting cavity C-5, the outlet channel 1 C-3 and the large oil pipe A-8; Channel 2 is composed of the small insulating oil pipe A-4, the oil pipe channel C-2, the outlet channel 2 C-4 and the small oil pipe A-9.

[0028] The downhole safety control system includes a high-temperature downhole packer B-3, a high-temperature exhaust valve B-2, a high-temperature downhole safety valve B-4, a high-temperature downhole check valve B-5 and a hydraulic control pipeline B-1.

[0029] Among them, the high-temperature exhaust valve B-2 is connected to the high-temperature downhole packer B-3, and the high-temperature downhole packer B-3 is connected to the large insulated oil pipe A-6, which can seal the annular space between the large insulated oil pipe A-6 and the production casing A-2. The high-temperature downhole safety valve B-4 is installed inside the dual-channel component A-7, which can seal the space inside the outlet channel C-4 inside the dual-channel component A-7. The high-temperature downhole single-flow valve B-5 is connected to the large oil pipe A-8, which can seal the space inside the large oil pipe A-8.

[0030] In this application, the high-temperature downhole packer B-3 provides safety control for the annulus between the insulation casing A-5 and the production casing A-2, the high-temperature downhole safety valve B-4 provides safety control for channel two, and the high-temperature downhole check valve B-5 provides safety control for channel one.

[0031] The working principle of the present invention is: using the dual-channel component A-7 to establish two independent fluid channels in a single wellbore, while having a downhole safety control function.

[0032] During the circulation preheating stage of the SAGD steam injection well, steam passes through the annulus of the insulating casing A-5, the large insulating oil pipe A-6 and the small insulating oil pipe A-4, the bridge channel C-1, the connecting cavity C-5, the outlet channel 1 C-3 and the large oil pipe A-8 into the toe of the horizontal section, and then returns to the small inclination A-10 through the large oil pipe A-8 and the screen pipe annulus, and returns to the wellhead through the small oil pipe A-9, the outlet channel 2 C-4, the oil pipe channel C-2 and the small insulating oil pipe A-4.

[0033] During the production stage of the SAGD steam injection well, steam enters the toe of the horizontal section through the annulus of the insulating casing A-5, the large insulating oil pipe A-6 and the small insulating oil pipe A-4, the bridge channel C-1, the connecting cavity C-5, the outlet channel 1 C-3 and the large oil pipe A-8, and enters the heel of the horizontal section through the small insulating oil pipe A-4, the oil pipe channel C-2, the outlet channel 2 C-4 and the small oil pipe A-9.

[0034] The embodiments of this specific implementation method are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A SAGD steam injection well integrated device for an offshore oil field, characterized in that: The invention comprises a SAGD steam injection well circulation preheating and continuous injection integrated process string and a downhole safety control system; the SAGD steam injection well circulation preheating and continuous injection integrated process string comprises an insulating sleeve (A-5), the upper end of the insulating sleeve (A-5) is connected to the casing hanger (A-3), the lower end of the insulating sleeve (A-5) is connected to a large insulating oil pipe (A-6), the lower end of the large insulating oil pipe (A-6) is connected to the outside of a dual-channel component (A-7); the inside of the dual-channel component (A-7) is connected to a small insulating oil pipe (A-3); The upper end of the small insulated oil pipe (A-4) is connected to the oil pipe hanger (A-1); the lower part of the dual-channel component (A-7) is respectively connected to the large oil pipe (A-8) and the small oil pipe (A-9); the large oil pipe (A-8) is connected through the annular space between the dual-channel component (A-7) and the insulation sleeve (A-5), the large insulated oil pipe (A-6) and the small insulated oil pipe (A-4); the small oil pipe (A-9) is connected to the small insulated oil pipe (A-4) through the dual-channel component (A-7).

2. The SAGD steam injection well integrated device for an offshore oil field according to claim 1, characterized in that: The dual-channel component (A-7) is divided into three parts, namely, an upper part, a middle part and a lower part, along the axial direction. The upper part of the dual-channel component (A-7) forms a through bridge channel (C-1), the lower part of the dual-channel component (A-7) forms a through outlet channel 1 (C-3) and an outlet channel 2 (C-4), and the middle part of the dual-channel component (A-7) forms a connecting cavity (C-5), the connecting cavity (C-5) connects the bridge channel (C-1) and the outlet channel 1 (C-3), and the outlet channel 1 (C-3) is connected to the large oil pipe (A-8); an oil pipe channel (C-2) is also formed in the center of the dual-channel component (A-7) along its axial direction, the oil pipe channel (C-2) connects the small heat-insulated oil pipe (A-4) and the outlet channel 2 (C-4), and the outlet channel 2 (C-4) is connected to the small oil pipe (A-9).

3. The SAGD steam injection well integrated device for an offshore oil field according to claim 1, characterized in that: The downhole safety control system includes a high-temperature exhaust valve (B-2), the high-temperature exhaust valve (B-2) and the high-temperature downhole packer (B-3), the high-temperature downhole packer (B-3) and the large insulated oil pipe (A-6) are connected to seal the annular space between the large insulated oil pipe (A-6) and the production casing (A-2).

4. The SAGD steam injection well integrated device for an offshore oil field according to claim 1, characterized in that: The downhole safety control system comprises a high-temperature downhole safety valve (B-4), which is arranged inside the dual-channel component (A-7) to seal the space inside the outlet channel 2 (C-4) tube inside the dual-channel component (A-7).

5. The SAGD steam injection well integrated device for an offshore oil field according to claim 1, characterized in that: The downhole safety control system comprises a high-temperature downhole check valve (B-5), which is connected to a large oil pipe (A-8) to seal the inner space of the large oil pipe (A-8).

6. The SAGD steam injection well integrated device for an offshore oil field according to claim 1, characterized in that: The lower end of the large oil pipe (A-8) is connected to the large incline (A-11).

7. The SAGD steam injection well integrated device for an offshore oil field according to claim 1, characterized in that: The lower end of the small oil pipe (A-9) is connected to the small guide bevel (A-10).