Injection-production integrated pipe column system

Abstract

The invention provides an injection-production integrated tubular column system, and relates to the technical field of thickened oil production, the device comprises an outer layer tubular column assembly, an inner layer tubular column assembly, an outer layer oil pipe, a heat insulation pipe assembly, an underground thermal power generator and a switching tool, the outer layer oil pipe is connected with the thermal power generator through the switching tool, and the heat insulation pipe assembly is connected with the outer layer tubular column assembly; the heat insulation pipe assembly is connected to the lower portion of the thermal power generator, and the bottom of the heat insulation pipe assembly is connected with a common oil pipe. The inner-layer pipe column assembly comprises an inner-layer oil pipe which is concentric with the outer-layer oil pipe and a switching insertion pipe which is used for connecting the inner-layer oil pipe with the switching tool; the multi-channel tubular column is connected with the thermal generator; the conveying pipeline assembly comprises a plurality of conveying pipelines and is used for being connected with the outer-layer pipe column assembly. Thermal fluid can be generated through underground combustion, heat loss and carbon emission can be greatly reduced, rapid injection and production integration is achieved, the operation period is shortened, the operation cost is reduced, and the thermal production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of heavy oil exploitation, and particularly to an integrated injection-production string system. Background Art

[0002] Heavy oil reservoirs have great development potential, but the development is difficult. Especially for highly viscous heavy oil, it has characteristics such as high viscosity and large frictional force, with large flow resistance in the reservoir and wellbore, and it cannot be efficiently exploited. Moreover, restricted by the small area of offshore platforms and difficult transportation, the thermal recovery of offshore heavy oil is very difficult.

[0003] Currently, the conventional heat injection technology mainly prepares hot fluid on the ground and then injects it into the reservoir through the wellbore. During the injection process, the entire wellbore is in a high-temperature working condition, which has stricter requirements for the material and size of downhole strings and tools, increasing the completion investment; the greenhouse gases generated during the heat injection process are directly emitted, and the heat loss of surface pipelines and wellbores is serious, which not only increases the ground heating cost but also makes it difficult for parameters such as the temperature and dryness of the hot fluid after reaching the bottom of the well to meet the design requirements, affecting the heat injection quality and the heavy oil exploitation effect.

[0004] The existing two-trip injection-production strings are that when injecting steam, the injection string is lowered, and when producing, the injection string is retrieved, and then the production string is lowered. The injection-production process requires string replacement, which has problems such as long operation time, high workover cost, and cold damage to the oil layer caused by the well flushing fluid during the workover process.

[0005] Therefore, there is an urgent need for an integrated injection-production string system to solve the above technical problems. Summary of the Invention

[0006] The purpose of the present invention is to provide an integrated injection-production string system, which can generate hot fluid by in-well combustion, greatly reduce heat loss and carbon emissions, and at the same time can achieve rapid integrated injection-production, shorten the operation cycle, reduce the operation cost, and improve the thermal recovery efficiency. The preferred technical solutions among the many technical solutions provided by the present invention can produce many technical effects as described below.

[0007] To achieve the above purpose, the present invention provides the following technical solutions:

[0008] An integrated injection-production string system provided by the present invention includes:

[0009] An outer string assembly, including an outer oil pipe, a heat insulation pipe assembly, a downhole thermal generator, and a transfer tool. Among them, the outer oil pipe is connected to the thermal generator through the transfer tool, the heat insulation pipe assembly is connected below the thermal generator, and the bottom of the heat insulation pipe assembly is connected to a common oil pipe;

[0010] Inner string assembly, including an inner tubing concentrically arranged with the outer tubing and an adapter spool for connecting the inner tubing to the adapter tool;

[0011] Multi-channel string, connected to the thermal generator;

[0012] Transport pipeline assembly, including a plurality of transport pipelines for connecting the outer string assembly.

[0013] Preferably, the heat insulation string assembly includes a first heat insulation pipe, a second heat insulation pipe and a third heat insulation pipe arranged in sequence from top to bottom, wherein:

[0014] One end of the first heat insulation pipe is connected to the thermal generator;

[0015] A two-way compensator is arranged between the first heat insulation pipe and the second heat insulation pipe;

[0016] A hydraulically controlled two-channel packer is arranged between the second heat insulation pipe and the third heat insulation pipe.

[0017] Preferably, the outer string assembly further includes a hydraulically controlled switch, a jet pump and a check valve, wherein:

[0018] The hydraulically controlled switch is arranged on the outer tubing;

[0019] The jet pump is arranged between the adapter tool and the outer tubing;

[0020] The check valve is arranged between the hydraulically controlled switch and the jet pump.

[0021] Preferably, the transport pipeline assembly includes an ignition cable and a switch hydraulically controlled pipeline, wherein:

[0022] The switch hydraulically controlled pipeline is connected to the hydraulically controlled switch;

[0023] The ignition cable is connected to the igniter of the thermal generator.

[0024] Preferably, the transport pipeline assembly further includes a packer hydraulically controlled pipeline and a gas release valve hydraulically controlled pipeline. A gas release valve is provided on the hydraulically controlled two-channel packer. The packer hydraulically controlled pipeline is connected to the hydraulically controlled two-channel packer, and the gas release valve hydraulically controlled pipeline is connected to the gas release valve.

[0025] Preferably, the injection-production integrated string system further includes an outer tubing hanger and an inner tubing hanger, wherein:

[0026] The outer tubing hanger is connected above the outer tubing;

[0027] The inner tubing hanger is connected above the inner tubing.

[0028] Preferably, the injection-production integrated string system further includes a downhole safety valve. The pipeline assembly includes a hydraulic control pipeline for the safety valve. The downhole safety valve is disposed between the third heat-insulating pipe and the hydraulic control double-channel packer, and the hydraulic control pipeline for the safety valve is connected to the downhole safety valve.

[0029] Preferably, the injection-production integrated string system further includes an injection valve and a sand control screen pipe, wherein:

[0030] The injection valve is disposed on the common tubing;

[0031] The sand control screen pipe is disposed on the periphery of the common tubing.

[0032] Preferably, the multi-channel string includes at least: a liquid injection channel, a fuel injection channel, and a gas injection channel, which are respectively used for delivering liquid, fuel, and air to the downhole heat generator.

[0033] Preferably, the first heat-insulating pipe, the second heat-insulating pipe, and the third heat-insulating pipe all adopt P110 high-vacuum or aerogel heat-insulating pipes;

[0034] The inner tubing adopts L80-13Cr or P110-13Cr airtight tubing.

[0035] The injection-production integrated string system provided by the present invention can directly inject heat into the reservoir by generating hot fluid with the downhole heat generator 10, so as to realize efficient heat injection and efficient production of the reservoir while solving the problems of serious wellbore heat loss and greenhouse gas emissions. By providing a concentric outer string assembly and an inner string assembly, and setting a multi-channel string and a pipeline assembly, air, water, and fuel can be respectively sent to the combustion chamber of the downhole heat generator 10 for mixing, and the fuel is ignited by the ignition cable of the pipeline assembly, so that the high-temperature and high-pressure multi-component thermal composite carrier generated by the combustion of the fuel in the combustion chamber flows into the formation through the heat-insulating pipe assembly, realizing direct downhole combustion to generate hot fluid and greatly reducing heat loss. This injection-production integrated string system realizes all process operations from heat injection to production through workover without pulling the string, meets the workover conditions of thermal recovery wells in heavy oil fields, avoids the problem of cold damage to the oil layer caused by well flushing during conventional workover, can shorten the workover cycle, reduce the workover cost, and improve the thermal recovery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0037] Figure 1 This is a schematic structural diagram of an embodiment of an integrated injection-production string system of the present invention.

[0038] In the figure: 1. Outer tubing hanger; 2. Outer layer tubing; 3. Inner layer tubing; 4. Jet pump; 5. Check valve; 6. Hydraulic control switch; 7. Thread adapter; 8. Transfer insert tube; 9. Transfer tool; 10. Thermal generator; 11. First heat insulation tube; 12. Bidirectional compensator; 13. Second heat insulation tube; 14. Hydraulic control two-way packer; 15. Third heat insulation tube; 16. Ordinary tubing; 17. Injection allocation valve; 18. Sand control screen pipe; 19. Inner tubing hanger; 20. Downhole safety valve; 21. Casing; a. Ignition cable; b. Fuel pipeline; c. Packer hydraulic control pipeline; d. Bleed valve hydraulic control pipeline; e. Optical cable; f. Switch hydraulic control pipeline; g. Safety valve hydraulic control pipeline. Specific embodiments

[0039] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without any creative work shall fall within the scope protected by the present invention.

[0040] In the description of the present invention, it should be understood that the terms "center", "lateral", "length", "width", "height", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "side", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0041] In the description of the present invention, it should also be noted that unless otherwise clearly defined and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] Figure 1 This is a schematic structural diagram of this embodiment. As Figure 1 shown, this embodiment provides an integrated injection-production string system, including an outer string assembly, an inner string assembly, a multi-channel string, and a delivery pipeline assembly.

[0043] Among them, the outer string assembly includes an outer tubing 2, a heat insulation string assembly, a downhole thermal generator 10, and an adapter tool 9. The outer tubing 2 is connected to the downhole thermal generator 10 through the adapter tool 9. The adapter tool 9 is a high-temperature adapter tool, which provides the functions of a sealed water path and a gas path for the downhole thermal generator 10. The heat insulation string assembly is connected below the thermal generator 10, and the bottom of the heat insulation string assembly is connected to a common tubing 16. The common tubing 16 in this embodiment is a 2-7 / 8" chamfered tubing.

[0044] Preferably, the thermal generator 10 adopted in this embodiment can operate at 350 °C and 21 MPa, with reliable performance, and is particularly suitable for the operating conditions of thermal recovery wells in offshore oilfields.

[0045] Conventional heat injection technologies mainly prepare hot fluids on the ground and then inject them into the reservoir through the wellbore. This integrated injection-production string system uses a downhole thermal generator 10 to directly inject the generated hot fluids into the reservoir, solving the problems of serious wellbore heat loss and greenhouse gas emissions.

[0046] The inner string assembly includes an inner tubing 3 concentrically arranged with the outer tubing 2 and an adapter insert 8 for connecting the inner tubing 3 and the adapter tool 9. The inner string assembly is sleeved inside the outer string assembly, and the connection parts are sealed and connected by threads. The inner tubing 3 in this embodiment adopts a 2-7 / 8" L80-13Cr or P110-13Cr gas-tight tubing, and the upper part of the inner tubing 3 is connected to an inner tubing hanger 19.

[0047] The multi-channel string (not shown in the figure) is connected to the thermal generator 10; the multi-channel string in this embodiment includes at least an injection liquid channel, an injection fuel channel, and an injection gas channel, which are respectively used to transport liquid, fuel, and air for the downhole thermal generator 10. Among them, the liquid includes water. The pipeline assembly includes a plurality of pipelines for connecting the outer string assembly.

[0048] This integrated injection-production string system directly injects heat into the reservoir using the hot fluid generated by the downhole heat generator 10. It can achieve efficient reservoir heat injection while realizing efficient reservoir production, solving the problems of serious wellbore heat loss and greenhouse gas emissions. By setting concentric outer string components and inner string components, and setting multi-channel strings and transportation pipeline components, air, water, and fuel can be sent to the combustion chamber of the downhole heat generator 10 for mixing respectively. Ignited by the ignition cable of the transportation pipeline component, the high-temperature and high-pressure multi-component thermal composite carrier generated by the combustion of the fuel in the combustion chamber flows into the formation through the heat insulation pipe component, realizing direct downhole combustion to generate hot fluid, greatly reducing heat loss, and achieving efficient reservoir heat injection. This integrated injection-production string system realizes all process operations from heat injection to production through workover without pulling the string, meets the operating conditions of thermal recovery wells in heavy oil fields, avoids the problem of cold damage to the oil layer caused by well flushing during conventional workovers, can shorten the operation cycle, reduce the operation cost, and improve the thermal recovery efficiency.

[0049] As an alternative embodiment, the heat insulation pipe component includes a first heat insulation pipe 11, a second heat insulation pipe 13, and a third heat insulation pipe 15 arranged in sequence from top to bottom.

[0050] Among them, one end of the first heat insulation pipe 11 is connected to the heat generator 10; a two-way compensator 12 is arranged between the first heat insulation pipe 11 and the second heat insulation pipe 13; a hydraulic control two-channel packer 14 is arranged between the second heat insulation pipe 13 and the third heat insulation pipe 15.

[0051] As Figure 1 shown, the outer string component in this embodiment is sequentially provided with an outer oil pipe 2, a first heat insulation pipe 11, a second heat insulation pipe 13, a third heat insulation pipe 15, and a common oil pipe 16 from top to bottom. Among them, the outer oil pipe 2 is an anti-corrosion oil pipe, its upper end is connected to the outer oil pipe hanger 1, and its lower end is connected to the high-temperature transfer tool 9; the upper end of the first heat insulation pipe 11 is connected to the heat generator 10, and the lower end is connected to the two-way compensator 12. The two-way compensator 12 is a high-temperature two-way compensator, which can realize two-way compensation of the string, and can compensate both the deformation amount of the string contraction generated under the water injection condition and the elongation deformation amount of the string under the heat injection state; the upper end of the second heat insulation pipe 13 is connected to the high-temperature two-way compensator 12, and the lower end is connected to the hydraulic control two-channel packer 14; the upper end of the third heat insulation pipe 15 is connected to the hydraulic control two-channel packer 14, and the lower end is connected to the common oil pipe 16.

[0052] The first heat insulation pipe 11, the second heat insulation pipe 13, and the third heat insulation pipe 15 in this embodiment are all 4-1 / 2" P110 high-vacuum or aerogel heat insulation pipes, which can effectively improve the steam dryness and play a role in protecting the casing 21.

[0053] As an alternative embodiment, the outer string component further includes a hydraulic control switch 6, a jet pump 4, and a check valve 5.

[0054] Among them, the hydraulic control switch 6 is arranged on the outer layer of the oil pipe 2. The hydraulic control switch 6 is used to provide a flow channel for the oil-casing annulus space between the outer layer of the oil pipe 2 and the casing 21 for this integrated injection-production pipe string system. By adopting the method of arranging the hydraulic control switch, the opening and closing of injection and production can be controlled, which is convenient and reliable.

[0055] The jet pump 4 is arranged between the adapter tool 9 and the outer layer of the oil pipe 2; the check valve 5 is arranged between the hydraulic control switch 6 and the jet pump 4. The jet pump 4 in this embodiment is located in the upper layer of the integrated injection-production pipe string system, and a check valve 5 is arranged at the lower end of the jet pump 4. During production, the power fluid is injected from the inner layer of the oil pipe 3, the hydraulic control switch 6 is opened, the formation fluid is sucked from the oil-casing annulus through the hydraulic control switch 6 and mixed with the power fluid and enters the inner layer of the oil pipe 3. Under the action of the jet pump 4, the mixed fluid is lifted to the ground, and the check valve 5 can prevent the mixed fluid from flowing back.

[0056] As an optional implementation manner, the transportation pipeline assembly includes an ignition cable a and a switch hydraulic control pipeline f. Among them, the switch hydraulic control pipeline f is connected to the hydraulic control switch 6; the ignition cable a is connected to the igniter of the downhole heat generator 10, and the ignition cable a extends into the interior of the downhole heat generator 10 to provide energy for the fuel to burn in the combustion chamber.

[0057] Specifically, the transportation pipeline assembly further includes a packer hydraulic control pipeline c and a gas release valve hydraulic control pipeline d. A large-flow channel gas release valve is provided on the hydraulic control double-packer 14. The packer hydraulic control pipeline c is connected to the hydraulic control double-packer 14, and the gas release valve hydraulic control pipeline d is connected to the gas release valve.

[0058] Optionally, the integrated injection-production pipe string system in this embodiment further includes a downhole safety valve 20. The transportation pipeline assembly includes a safety valve hydraulic control pipeline g. The downhole safety valve 20 is arranged between the third heat insulation pipe 15 and the hydraulic control double-packer 14, and the safety valve hydraulic control pipeline g is connected to the downhole safety valve 20.

[0059] The hydraulic control pipeline in this embodiment is a 1 / 4in 825 or 625 hydraulic control pipeline.

[0060] As an optional implementation manner, the integrated injection-production pipe string system further includes an injection allocation valve 17 and a sand control screen pipe 18. Among them, the injection allocation valve 17 is arranged on the ordinary oil pipe 16; the sand control screen pipe 18 is arranged on the periphery of the ordinary oil pipe 16.

[0061] The operation method of this embodiment includes: before heat injection, set the hydraulic control double-channel packer 14, open the hydraulic control downhole safety valve for thermal recovery 20, close the hydraulic control switch 6, and at the same time inject nitrogen into the annulus between the casing and the tubing; during steam injection, close the hydraulic control switch 6, and at the same time convey water, fuel and air to the coiled tubing multi-channel string, and the high-temperature and high-pressure multi-component thermal composite carrier generated by combustion enters the first heat-insulating pipe 11 and is finally injected into the formation through the ordinary tubing 16; after steam injection, during production, lower the pump core of the jet pump 4, open the hydraulic control switch 6, the power fluid is injected from the inner tubing 3, and the formation fluid enters the inner tubing 3 from the annulus between the casing and the tubing through the hydraulic control switch 6 and is produced from the inner tubing 3 after mixing with the power fluid.

[0062] As mentioned above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. An injection-production integrated string system, characterized in that: include: An outer tubular column assembly, comprising an outer oil pipe, an insulation pipe assembly, a downhole thermal generator and a switching tool, wherein the outer oil pipe is connected to the thermal generator via a switching tool, the insulation pipe assembly is connected below the thermal generator, and the bottom of the insulation pipe assembly is connected to a common oil pipe; An inner layer tubing assembly, comprising an inner layer tubing arranged concentrically with the outer layer tubing and a transition plug for connecting the inner layer tubing with the transition tool; A multi-channel pipe column connected to the thermal generator; The delivery pipeline assembly comprises a plurality of delivery pipelines and is used to connect the outer layer pipe string assembly.

2. The injection-production integrated string system according to claim 1, characterized in that: The thermal insulation pipe assembly comprises a first thermal insulation pipe, a second thermal insulation pipe and a third thermal insulation pipe arranged in sequence from top to bottom, wherein: One end of the first thermal insulation tube is connected to the thermal generator; A bidirectional compensator is arranged between the first thermal insulation tube and the second thermal insulation tube; A hydraulically controlled dual-channel packer is arranged between the second thermal insulation tube and the third thermal insulation tube.

3. The injection-production integrated string system according to claim 2, characterized in that: The outer tubular column assembly further comprises a hydraulically controlled switch, a jet pump and a check valve, wherein: The hydraulically controlled switch is arranged on the outer oil pipe; The jet pump is arranged between the adapter tool and the outer oil pipe; The check valve is arranged between the hydraulically controlled switch and the jet pump.

4. The injection-production integrated string system according to claim 3, characterized in that: The delivery pipeline assembly includes an ignition cable and a switch hydraulic control pipeline, wherein: The switch hydraulic control pipeline is connected to the hydraulic control switch; The ignition cable is connected to the igniter of the thermal generator.

5. The injection-production integrated string system according to claim 4, characterized in that: The delivery pipeline assembly also includes a packer hydraulic control pipeline and a bleed valve hydraulic control pipeline. The hydraulically controlled dual-channel packer is provided with a bleed valve. The packer hydraulic control pipeline is connected to the hydraulically controlled dual-channel packer, and the bleed valve hydraulic control pipeline is connected to the bleed valve.

6. An injection-production integrated string system according to any one of claims 1 to 5, characterized in that: The injection-production integrated tubing system further comprises an outer tubing hanger and an inner tubing hanger, wherein: The outer oil pipe hanger is connected to the upper part of the outer oil pipe; The inner oil pipe hanger is connected above the inner layer oil pipe.

7. An injection-production integrated tubing string system according to any one of claims 2 to 5, characterized in that: The integrated injection-production tubing system also includes a downhole safety valve. The delivery pipeline assembly includes a safety valve hydraulic control pipeline. The downhole safety valve is arranged between the third insulation pipe and the hydraulically controlled dual-channel packer. The safety valve hydraulic control pipeline is connected to the downhole safety valve.

8. An injection-production integrated string system according to any one of claims 1 to 5, characterized in that: The injection-production integrated tubing system also includes an injection valve and a sand control screen, wherein: The injection valve is arranged on the common oil pipe; The sand control screen is arranged on the peripheral side of the common oil pipe.

9. An injection-production integrated string system according to any one of claims 1 to 5, characterized in that: The multi-channel tubing string at least comprises: a liquid injection channel, a fuel injection channel and a gas injection channel, which are used to transport liquid, fuel and air to the downhole thermal generator respectively.

10. An injection-production integrated string system according to any one of claims 2 to 5, characterized in that: The first thermal insulation tube, the second thermal insulation tube, and the third thermal insulation tube are all P110 high vacuum or aerogel thermal insulation tubes; The inner layer oil pipe is made of L80-13Cr or P110-13Cr airtight oil pipe.

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