An offshore platform autogenic carbon source CCUS device and process

Abstract

The application belongs to the technical field of offshore platform carbon dioxide flooding, and discloses a safe, efficient, economic and feasible offshore platform autogenic carbon source CCUS device and process. The device comprises an oil-gas separator, a membrane separation device, first and second compression assemblies and a bypass pipeline. The outlets of the first and second compression assemblies are connected with a CCS storage well and a CCUS effective well respectively. The inlet of the oil-gas separator is connected with the outlets of a high-carbon gas source well and the CCUS effective well. One end of the bypass pipeline is connected between the oil-gas separator and the membrane separation device, and the other end is connected between the membrane separation device and the first compression assembly. In the non-overload mode, the output gas of the high-carbon gas source well and the CCUS effective well is sent to the CCUS effective well through the oil-gas separator, the membrane separation device, the first compression assembly and / or the second compression assembly. In the overload mode, the CO2 of the high-carbon gas source well and the CCUS effective well is sent to the CCS storage well through the oil-gas separator, the bypass pipeline and the first compression assembly, and the rest is sent to the CCUS effective well through the membrane separation device and the second compression assembly.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide flooding technology for offshore platforms, specifically to a self-generated carbon source (CCUS) device and process for offshore platforms. Background Technology

[0002] Carbon capture, utilization, and storage (CCUS) is receiving increasing attention as an effective means of carbon reduction. Injecting CO2 gas into an oil reservoir can reduce the viscosity of crude oil and the interfacial tension between oil and water, causing the crude oil to expand in volume. Under specific pressure, CO2 can achieve miscible displacement with the crude oil, thereby improving oil recovery.

[0003] Offshore oil and gas production platforms face significant challenges due to their limited space, high safety requirements, and limited area. These challenges include: 1. The CCUS process involves complex components such as oil and gas separation, dehydration, dehydrogenation, capture, and pressurization units, requiring large floor space. Offshore platforms have limited space, necessitating process optimization to meet offshore construction requirements. For example, a CO2 circulation injection station in Liaohe Oilfield occupies over 13,000 square meters, which is difficult for offshore platforms to accommodate. 2. As CCUS operations progress, CO2 production from CCUS-affected wells will increase significantly, leading to substantial fluctuations in the amount of gas to be separated throughout the CCUS operation, making it difficult to match the platform's capture equipment. 3. A significant increase in platform carbon sources in the later stages of the project, coupled with the CCUS project's requirement for stable CO2 injection to ensure oil displacement, will cause problems with carbon source matching, leaving excess CO2 after capture and separation unprocessed.

[0004] Currently, CCUS in offshore oil and gas fields at home and abroad is still in its initial stage, mainly focusing on carbon dioxide marine transportation, safe release of carbon dioxide, research and development of injection tubing and parameter optimization, etc. There are few reports on research schemes for CCUS process flow design of offshore platform systems. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention proposes a safe, efficient, and economically feasible CCUS device and process for offshore platforms.

[0006] The offshore platform CCUS device according to the present invention includes: an oil-gas separator, a membrane separation unit connected to the oil-gas separator, a first compression assembly and a second compression assembly arranged in parallel and simultaneously connected to the outlet of the membrane separation unit, and a bypass line. The first compression assembly is connected to a CCS storage well, the second compression assembly is connected to a CCUS receiving well, the inlet of the oil-gas separator is connected to a high-carbon gas source well, the outlet of the CCUS receiving well is connected to the inlet of the oil-gas separator, and one end of the bypass line is connected between the oil-gas separator and the membrane separation unit, and the other end is connected to the membrane separation unit. Between the separation device and the first compression assembly, the offshore platform CCUS device is configured to have a non-overload mode: produced gas from the high-carbon gas source well and the CCUS-effected well passes sequentially through an oil-gas separator, a membrane separator, and then through the first compression assembly and / or the second compression assembly into the CCUS-effected well; and an overload mode: produced gas from the high-carbon gas source well and the CCUS-effected well passes through an oil-gas separator, and a portion of it passes through a bypass pipeline into the first compression assembly and then into the CCS storage well, while the other portion passes through the membrane separator into the second compression assembly and then into the CCUS-effected well.

[0007] Furthermore, a first shut-off valve, a first regulating valve, a first gas flow meter, and a second shut-off valve are sequentially installed on the bypass pipeline. The membrane separation unit is connected to the first compression assembly via the first pipeline. One end of the bypass pipeline is connected to the first pipeline. A third shut-off valve is installed on the first pipeline. The first compression assembly is connected to the CCS storage well via the second pipeline. The second compression assembly is connected to the CCUS effective well via the third pipeline. A fourth pipeline connects the second and third pipelines. A fourth shut-off valve is installed on the fourth pipeline. A normally closed shut-off valve is installed in the area between the fourth shut-off valve and the CCS storage well on the second pipeline. In overload mode, the first shut-off valve, the first regulating valve, the second shut-off valve, and the normally closed shut-off valve are open, while the third and fourth shut-off valves are closed. In non-overload mode, the first shut-off valve, the second shut-off valve, and the normally closed shut-off valve are closed, while the third and fourth shut-off valves are open.

[0008] Furthermore, a gas sampling port is provided between the first gas flow meter and the second shut-off valve.

[0009] Furthermore, the oil-gas separator and the membrane separation device are connected through a fifth pipeline, on which a second gas flow meter, a second regulating valve, and a third gas flow meter are sequentially installed. A bypass pipeline is connected to the area on the fifth pipeline located between the second gas flow meter and the second regulating valve.

[0010] Furthermore, the oil-gas separator is connected to the high-carbon gas source well via the sixth pipeline, on which a first multiphase flow meter is installed. The CCUS-affected well is connected to the sixth pipeline via the seventh pipeline, on which a second multiphase flow meter is installed. The first multiphase flow meter is located at the front end of the connection between the seventh and sixth pipelines.

[0011] Furthermore, a supercritical carbon dioxide flow meter is also installed on the third pipeline to measure the amount of CO2 gas injected into the CCUS-receiving well.

[0012] Furthermore, the first compression assembly includes at least two compressor stages connected in series.

[0013] Furthermore, molecular sieve dehydration devices are connected between adjacent compressor stages.

[0014] Furthermore, the second compression component is the same as the first compression component.

[0015] According to the offshore platform CCUS process of the present invention, the application of the above-mentioned offshore platform CCUS device includes: when the sum of the produced gas volume of the platform's high-carbon gas source well and the CCUS-affected well is less than or equal to the gas volume corresponding to the processing capacity of the membrane separation device, the offshore platform CCUS device is activated in a non-overload mode; when the sum of the produced gas volume of the platform's high-carbon gas source well and the CCUS-affected well is greater than the gas volume corresponding to the processing capacity of the membrane separation device, the offshore platform CCUS device is activated in an overload mode.

[0016] Compared with the prior art, the offshore platform CCUS device and process of the present invention have the following advantages:

[0017] 1) Scientific setup: The offshore platform CCUS device and process of this invention are designed for the limited space at sea. It can realize the entire process of carbon separation, compression and reinjection on a single platform. It solves the problems of increased gas volume to be processed on the surface after the CO2 produced by the CCUS effective well breaks through, equipment overload caused by large fluctuations in carbon source, and the problem of CO2 consumption being lower than gas source volume due to the adjustment of injection well process parameters. It can effectively reduce equipment investment and meet the needs of field application.

[0018] 2) Excellent economic efficiency: The offshore platform CCUS device and process of this invention optimizes the offshore CCUS process flow for the platform's self-generated carbon source. Throughout the process, CO2 remains in the gas phase without phase change, reducing equipment requirements and eliminating the need for additional energy consumption. The integrated sealing and flooding design reduces the processing capacity requirements of the membrane separation unit, thus reducing both platform area requirements and equipment investment.

[0019] 3) Promoting technological development: Currently, there is no offshore CCUS business in China. This invention will help offshore oil and gas fields to carry out CCUS business by optimizing carbon sources and process design, which will help promote the development of offshore CCUS business and also help the advancement of offshore CCUS technology in multiple modes such as ship transportation of carbon sources and pipeline transportation of carbon sources. Attached Figure Description

[0020] Figure 1This is a schematic diagram of the structure of a CCUS device for an offshore platform according to an embodiment of the present invention. Detailed Implementation

[0021] To better understand the purpose, structure, and function of this invention, the invention will be described in further detail below with reference to the accompanying drawings.

[0022] Figure 1 The structure of a CCUS device 100 for an offshore platform according to an embodiment of the present invention is shown. Figure 1 As shown, the offshore platform CCUS device 100 may include: an oil-gas separator 2, a membrane separator 6 connected to the oil-gas separator 2, a first compression assembly 30 and a second compression assembly 40 arranged in parallel and simultaneously connected to the outlet of the membrane separator 6, and a bypass line 13. The first compression assembly 30 is connected to a CCS (Carbon Capture and Storage) well 60, the second compression assembly 40 is connected to a CCUS receiving well 70, the inlet of the oil-gas separator 2 is connected to a high-carbon gas source well 50, the outlet of the CCUS receiving well 70 is connected to the inlet of the oil-gas separator 2, one end of the bypass line 13 is connected between the oil-gas separator 2 and the membrane separator 6, and the other end is connected between the membrane separator 6 and the first compression assembly 30. The offshore platform CCUS device 100 is configured to have a non-overload mode: from high-carbon gas... The produced gas from source well 50 and CCUS effective well 70 passes sequentially through oil-gas separator 2 and membrane separator 6, and then enters CCUS effective well 70 through first compression assembly 30 and / or second compression assembly 40; and in overload mode: the produced gas from high carbon gas source well 50 and CCUS effective well 70 passes through oil-gas separator 2, and then enters first compression assembly 30 through bypass pipeline 13 and then enters CCS storage well 60, while the other part passes through membrane separator 6 and then enters second compression assembly 40 and then enters CCUS effective well 70.

[0023] In the offshore platform CCUS device of this invention embodiment, considering the limited area of ​​the offshore platform, a membrane separation device 6 is equipped according to the CCUS injection process parameter requirements. The CO2 produced by the inherent high-carbon gas source well 50 is directly applied to the production of the CCUS receiving well 70, which can effectively improve the utilization efficiency of CO2 and reduce production costs. At the same time, the produced gas in the CCUS receiving well 70 enters the membrane separation device 6 for processing through the oil-gas separator 2. The separated high-hydrocarbon gas enters the natural gas pipeline network, and the separated CO2 is reinjected into the CCUS receiving well 70 through the first compression component 30 and / or the second compression component 40. In the early stages of the CCUS project, the membrane separation unit 6 can handle the load of produced gas from the CCUS receiving well 70 and the high-carbon gas source well 50. At this time, all CO2 can be compressed by the first compression component 30 and / or the second compression component 40 and then injected into the CCUS receiving well 70 for production. In the later stages of the CCUS project, the produced gas volume of the CCUS receiving well 70 increases significantly. The excess gas volume can be directly compressed and injected into the CCS storage well 60 without separation by the membrane separation unit 6. This setup can simultaneously solve problems such as the need for precise CCUS injection, the periodic fluctuations of offshore gas sources, and the limited space on the offshore platform. To enable simultaneous injection into the CCUS receiving well 70 and the CCS storage well 60, the first compression component 30 and the second compression component 40 can be configured according to the peak gas volume. That is, in the early stages of the project, one of the first compression component 30 and the other of the second compression component 40 will be in use and the other will be on standby. Once the peak gas volume is reached, the equipment can operate at full capacity.

[0024] The technical approach of this invention is to optimize the surface oil and gas separation, carbon separation, compression, and injection processes by combining the design principles of onshore CO2 recirculation injection stations with the current status of offshore oil and gas separation and decarbonization technologies. Adopting an integrated sealing and flooding design concept, two backup emergency pipelines were designed: one for direct compression injection into the CCUS effective well 70 after carbon source separation, and another for direct injection of excess carbon source into the CCS storage well 60. This solves the problems of increased platform CO2 volume leading to overload of the membrane separator 6 and the difficulty in handling CO2 due to the platform's CO2 source exceeding the design injection volume in the later stages of the CCUS project. It enables CCUS operations within the limited space of an offshore oil and gas platform and allows for long-term full-load operation of the equipment even under fluctuating gas source and injection parameters, thereby effectively reducing investment in surface equipment and improving equipment utilization.

[0025] In such Figure 1In the preferred embodiment shown, a first shut-off valve 16, a first regulating valve 17, a first gas flow meter 18, and a second shut-off valve 20 are sequentially installed on the bypass line 13. The membrane separation device 6 is connected to the first compression assembly 30 via the first line 102. One end of the bypass line 13 is connected to the first line 102. A third shut-off valve 7 is installed on the first line 102. The first compression assembly 30 is connected to the CCS storage well 60 via the second line 104. The second compression assembly 40 is connected to the CCUS effective well 70 via the third line 105. The second line 104 is connected to the first... A fourth pipeline 107 is connected between the three pipelines 105. A fourth shut-off valve 11 is installed on the fourth pipeline 107. A normally closed shut-off valve 21 is installed on the second pipeline 104 in the area between the fourth shut-off valve 11 and the CCS storage well 60. In overload mode, the first shut-off valve 16, the first regulating valve 17, the second shut-off valve 20 and the normally closed shut-off valve 21 are open, and the third shut-off valve 7 and the fourth shut-off valve 11 are closed. In non-overload mode, the first shut-off valve 16, the second shut-off valve 20 and the normally closed shut-off valve 21 are closed, and the third shut-off valve 7 and the fourth shut-off valve 11 are open.

[0026] Preferably, such as Figure 1 As shown, a gas sampling port 19 is also provided between the first gas flow meter 18 and the second shut-off valve 20. This gas sampling port 19 can be used to sample the gas that has not passed through the membrane separation device 6, and the CO2 gas content in the gas sample can be obtained through indoor tests, thereby obtaining the gas content of CO2 sealed in the CCS well.

[0027] In such Figure 1 In the preferred embodiment shown, the oil-gas separator 2 and the membrane separator 6 are connected via a fifth pipeline 108. A second gas flow meter 3, a second regulating valve 4, and a third gas flow meter 5 are sequentially installed on the fifth pipeline 108. A bypass pipeline 13 connects to the area on the fifth pipeline 108 located between the second gas flow meter 3 and the second regulating valve 4. In this embodiment, the second gas flow meter 3 obtains the total amount of gas requiring CO2 separation. If the gas volume is higher than the processing capacity of the membrane separator 6, an overload mode is activated; if the gas volume is lower than the processing capacity of the membrane separator 6, an unloaded mode is activated. The third gas flow meter 5 and the first gas flow meter 18 respectively obtain the gas volume entering the membrane separator 6 and the gas volume directly compressed and injected into the CCS storage well 60.

[0028] Furthermore, such as Figure 1As shown, the oil-gas separator 2 is connected to the high-carbon gas source well 50 via a sixth pipeline 101. A first multiphase flow meter 1 is installed on the sixth pipeline 101. The CCUS-affected well 70 is connected to the sixth pipeline 101 via a seventh pipeline 106. A second multiphase flow meter 22 is installed on the seventh pipeline 106. The first multiphase flow meter 1 is located at the front end of the connection between the seventh pipeline 106 and the sixth pipeline 101. In this embodiment, the first multiphase flow meter 1 is used to monitor the oil and gas production of the high-carbon gas source well 50, and the second multiphase flow meter 22 is used to monitor the oil and gas production of the CCUS-affected well 70. The total amount of oil and gas that the oil-gas separator 2 needs to process can be obtained from these two data points.

[0029] Furthermore, such as Figure 1 As shown, a supercritical carbon dioxide flow meter 15 is also installed on the third pipeline 105 to measure the amount of CO2 gas injected into the CCUS effective well 70. This supercritical carbon dioxide flow meter 15 is used to measure the amount of CO2 gas injected into the CCUS effective well 70. The second gas flow meter 3, combined with the supercritical carbon dioxide flow meter 15, can obtain the total amount of CO2 sealed in the CCS sealing well 60.

[0030] According to the present invention, the first compression assembly 30 may include at least two compressor stages connected in series to improve the compression efficiency of CO2 as needed. Preferably, as Figure 1 As shown, a molecular sieve dehydration device 9 is also connected between adjacent compressor stages. This molecular sieve dehydration device 9 is used to reduce the water content in CO2, thereby reducing the corrosive properties of CO2.

[0031] In such Figure 1 In the preferred embodiment shown, the first compression assembly 30 may include a first compressor 8 and a second compressor 10 connected in series, with a molecular sieve dehydration device 9 disposed between the first compressor 8 and the second compressor 10.

[0032] Furthermore, such as Figure 1 As shown, the second compression component 40 may be the same as the first compression component 30.

[0033] According to the offshore platform CCUS process of the present invention, the application of the above-mentioned offshore platform CCUS device 100 may include: when the sum of the produced gas volume of the platform's high-carbon gas source well 50 and the CCUS effective well 70 is less than or equal to the gas volume corresponding to the processing capacity of the membrane separation device 6, the offshore platform CCUS device 100 is activated in a non-overload mode; when the sum of the produced gas volume of the platform's high-carbon gas source well 50 and the CCUS effective well 70 is greater than the gas volume corresponding to the processing capacity of the membrane separation device 6, the offshore platform CCUS device 100 is activated in an overload mode.

[0034] In the offshore platform CCUS process of this invention embodiment, when the initial oil and gas production of the platform (the sum of the produced gas from the platform's high-carbon gas source well 50 and the CCUS-receiving well 70) is lower than the processing capacity of the membrane separator 6, the oil and gas produced from the platform's high-carbon gas source well enters the oil and gas separator 2 for gas-liquid separation. Natural gas enters the membrane separator 6, the separated high-hydrocarbon gas enters the natural gas pipeline network, and the separated CO2 is injected into the CCUS-receiving well 70 through the first compression component 30 and / or the second compression component 40. The oil and gas produced from the CCUS-receiving well 70 enters the oil and gas separator 2 together with the oil and gas produced from the high-carbon gas source well 50 through the seventh pipeline 106, and then enters the subsequent processing flow.

[0035] In the later stages of the project, when the platform's gas production exceeds the processing capacity of the membrane separator 6, the produced oil and gas are separated after passing through the oil-gas separator 2. Part of the separated gas is injected into the CCUS receiving well 70, and the remainder is injected into the CCS storage well. By opening the first shut-off valve 16, the first regulating valve 17, the second shut-off valve 20, and the normally closed shut-off valve 21, and closing the third shut-off valve 7 and the fourth shut-off valve 11, and adjusting the opening of the first regulating valve 17 and the second regulating valve 4, the CO2 separated by the membrane separator 6 meets the injection requirements of the CCUS receiving well 70 and is directly injected into the CCUS receiving well 70 through the second compression assembly 40. The remaining gas is injected into the CCS storage well 60 through the bypass pipeline 13 and the first compression assembly 30.

[0036] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0037] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A CCUS device for an offshore platform, characterized in that, include: The system includes an oil-gas separator, a membrane separation device connected to the oil-gas separator, a first compression assembly and a second compression assembly arranged in parallel and simultaneously connected to the outlet of the membrane separation device, and a bypass pipeline. The first compression assembly is connected to a CCS storage well, and the second compression assembly is connected to a CCUS receiving well. The inlet of the oil-gas separator is connected to a high-carbon gas source well, and the outlet of the CCUS receiving well is connected to the inlet of the oil-gas separator. One end of the bypass pipeline is connected between the oil-gas separator and the membrane separation device, and the other end is connected between the membrane separation device and the first compression assembly. The offshore platform CCUS device is configured to have a non-overload mode: produced gas from the high-carbon gas source well and the CCUS receiving well passes sequentially through the oil-gas separator and the membrane separation device, and then through the first compression assembly and / or the second compression assembly into the CCUS receiving well. Overload mode: The produced gas from the high-carbon gas source well and the CCUS-effected well passes through the oil-gas separator, and part of it enters the first compression assembly through the bypass pipeline and then enters the CCS storage well. The other part enters the second compression assembly through the membrane separation device and then enters the CCUS-effected well.

2. The offshore platform CCUS device according to claim 1, characterized in that, The bypass pipeline is sequentially equipped with a first shut-off valve, a first regulating valve, a first gas flow meter, and a second shut-off valve. The membrane separation device is connected to the first compression assembly via a first pipeline. One end of the bypass pipeline is connected to the first pipeline. A third shut-off valve is installed on the first pipeline. The first compression assembly is connected to the CCS storage well via a second pipeline. The second compression assembly is connected to the CCUS effective well via a third pipeline. A fourth pipeline connects the second pipeline and the third pipeline. A fourth shut-off valve is installed on the fourth pipeline. A normally closed shut-off valve is installed in the area between the fourth shut-off valve and the CCS storage well on the second pipeline. In the overload mode, the first shut-off valve, the first regulating valve, the second shut-off valve, and the normally closed shut-off valve are open, while the third shut-off valve and the fourth shut-off valve are closed. In the non-overload mode, the first shut-off valve, the second shut-off valve, and the normally closed shut-off valve are closed, while the third shut-off valve and the fourth shut-off valve are open.

3. The offshore platform CCUS device according to claim 2, characterized in that, A gas sampling port is also provided between the first gas flow meter and the second shut-off valve.

4. The offshore platform CCUS device according to claim 2, characterized in that, The oil-gas separator is connected to the membrane separation device via a fifth pipeline. A second gas flow meter, a second regulating valve, and a third gas flow meter are sequentially installed on the fifth pipeline. The bypass pipeline is connected to the area on the fifth pipeline located between the second gas flow meter and the second regulating valve.

5. The offshore platform CCUS device according to claim 4, characterized in that, The oil-gas separator is connected to the high-carbon gas source well via a sixth pipeline, on which a first multiphase flow meter is installed. The CCUS-affected well is connected to the sixth pipeline via a seventh pipeline, on which a second multiphase flow meter is installed. The first multiphase flow meter is located at the front end of the connection between the seventh and sixth pipelines.

6. The offshore platform CCUS device according to claim 5, characterized in that, The third pipeline is also equipped with a supercritical carbon dioxide flow meter, which is used to measure the amount of CO2 gas injected into the CCUS-receiving well.

7. The offshore platform CCUS device according to any one of claims 1 to 6, characterized in that, The first compression assembly includes at least two compressor stages connected in series.

8. The offshore platform CCUS device according to claim 7, characterized in that, A molecular sieve dehydration device is also connected between the compressors in adjacent stages.

9. The offshore platform CCUS device according to claim 7, characterized in that, The second compression component is the same as the first compression component.

10. A CCUS process for offshore platforms, employing the offshore platform CCUS device according to any one of claims 1 to 9, characterized in that, include: When the sum of the gas produced by the high-carbon gas source well and the CCUS-affected well of the platform is less than or equal to the gas volume corresponding to the processing capacity of the membrane separation device, the offshore platform CCUS device is activated in the non-overload mode; when the sum of the gas produced by the high-carbon gas source well and the CCUS-affected well of the platform is greater than the gas volume corresponding to the processing capacity of the membrane separation device, the offshore platform CCUS device is activated in the overload mode.

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