Valve group prying device suitable for well head gas recovery

Abstract

The utility model relates to a valve group prying device suitable for wellhead gas recovery. The valve group prying device comprises a wellhead gas inlet pipeline, a high-pressure pipeline, a low-pressure pipeline, a high-pressure gathering pipeline, a low-pressure gathering pipeline and a safe diffusion pipeline. According to the wellhead gas environment and using conditions, the wellhead gas recovery valve group prying device is developed, automatic shunting is achieved, through dual pressure reduction and hierarchical control, it is guaranteed that a stable gas source is conveyed to a downstream pipe network, the high-low pressure (1.6-35 MPa) gas conveying function is achieved, and the wellhead gas recovery rate is improved to the maximum extent.

Description

Technical Field

[0001] The utility model relates to a valve group skid device suitable for wellhead gas recovery, which can realize the recovery of wellhead gas with different pressures and achieve the maximum recovery rate at the same time. Background Art

[0002] At present, there are a large number of small natural gas wells in Shaanxi, Sichuan and other places in China, with a gas production of about 10,000 to 50,000 cubic meters. They are usually compressed into CNG or LNG for transportation to other places, or compressed to a certain pressure to enter the gas pipeline network. Conventional wellhead gas recovery first passes through the manifold to mix and stabilize the wellhead gases before entering the downstream pipeline.

[0003] The utility model is a wellhead gas recovery device that does not require an inlet gas manifold and ensures stable gas source delivery through double decompression and graded control. It is mainly used to transport wellhead gas to the downstream pipeline network, realize high and low pressure (1.6-35MPa) gas recovery and transmission functions, and realize wellhead gas recovery to the greatest extent possible. Utility Model Content

[0004] The utility model provides a pry device and process suitable for wellhead gas recovery valve group, which realizes one-key operation and partial pressure gas transmission function, automatically controls and adjusts according to the process, meets the needs of wellhead gas recovery and improves the maximum recovery rate. When wellhead gas is inlet, partial pressure transmission is automatically switched through pressure detection.

[0005] The utility model discloses a wellhead gas recovery valve group skid device, comprising one or more high-pressure wellhead gas inlet pipelines, one or more low-pressure wellhead gas inlet pipelines, more than two high-pressure pipelines, more than two low-pressure pipelines, a high-pressure aggregation pipeline, a low-pressure aggregation pipeline, one or more overpressure relief pipelines, a relief main pipe, a high-pressure aggregation pipeline relief pipeline, and a low-pressure aggregation pipeline relief pipeline.

[0006] Among them, one end of each high-pressure wellhead gas inlet pipeline is connected to a high-pressure wellhead (for example, the pressure is equal to or exceeds 9±0.5MPa, especially 9MPa), and the other end is connected to another low-pressure pipeline and another high-pressure pipeline through a three-way valve.

[0007] One end of each low-pressure wellhead gas inlet pipeline is connected to a low-pressure wellhead (for example, the pressure is lower than 9±0.5MPa, especially 9MPa), and the other end is connected to a low-pressure pipeline and a high-pressure pipeline through a three-way valve.

[0008] Each high-pressure wellhead gas inlet pipeline is equipped with a high-pressure valve, angle valve, check valve, and pressure transmitter in sequence along the gas inlet direction.

[0009] Each low-pressure wellhead gas inlet pipeline is equipped with a high-pressure valve, a check valve, and a pressure transmitter in sequence along the gas inlet direction.

[0010] All high-pressure pipelines are connected to the high-pressure pipeline through high-pressure valves, and all low-pressure pipelines are connected to the low-pressure pipeline through high-pressure valves.

[0011] An overpressure relief pipeline is drawn out between the check valve and the three-way valve of each high-pressure wellhead gas inlet pipeline. Each overpressure relief pipeline is equipped with a safety valve and merges into the relief main pipe.

[0012] The high-pressure collection pipeline leads to a high-pressure collection pipe release pipeline to the release main pipe. A safety valve is installed on the high-pressure collection pipe release pipeline.

[0013] The low-pressure collection pipeline leads to a low-pressure collection pipe release pipeline to the release main pipe. A safety valve is installed on the low-pressure collection pipe release pipeline.

[0014] A first cut-off valve and a first automatic pressure regulating valve are provided in sequence downstream of the low-pressure pipeline at the connection point between the low-pressure pipeline and the low-pressure pipeline.

[0015] A second shut-off valve, a heater, and a second automatic pressure regulating valve are sequentially arranged downstream of the high-pressure collecting pipeline at the connection point between the high-pressure pipeline and the high-pressure collecting pipeline.

[0016] Furthermore, a pressure transmitter and / or a temperature transmitter is provided downstream of the low-pressure collecting pipeline at the connection point between the low-pressure pipeline and the low-pressure collecting pipeline and after the first automatic pressure regulating valve.

[0017] Furthermore, a pressure transmitter and / or a temperature transmitter is provided downstream of the high-pressure merging pipeline at the connection point between the high-pressure pipeline and the high-pressure merging pipeline and after the second automatic pressure regulating valve.

[0018] The high-pressure valve is preferably a 35MPa high-pressure ball valve. Since the nominal diameter of the wellhead high-pressure valve is DN65, a 35MPa high-pressure valve is selected because it has good versatility and can meet the pressure requirements of different wells.

[0019] Furthermore, the heater is a three-speed heater. Through the control program setting, the first-speed heater is started when the temperature is lower than 0°C, the first and second-speed heaters are started when the temperature is lower than -5°C, the first, second and third-speed heaters are started when the temperature is lower than -10°C, and the heater stops heating when the temperature is higher than 5°C.

[0020] In the present application, all shut-off valves are preferably automatic shut-off valves, which fully automatically realize the opening and closing functions of each pipeline, and realize one-button start and stop of wellhead gas intake, diversion, and pressure regulation.

[0021] Furthermore, the wellhead gas with a pressure exceeding 9 MPa is connected to the high-pressure wellhead gas inlet pipeline; the wellhead gas with a pressure not exceeding 9 MPa is connected to the low-pressure wellhead gas inlet pipeline.

[0022] Furthermore, when the pressure transmitter detects that the pressure of the high-pressure wellhead gas inlet pipeline or the low-pressure wellhead gas inlet pipeline is greater than or equal to 4MPa, the inlet gas enters the high-pressure pipeline; when the pressure transmitter detects that the pipeline pressure is less than 4MPa, the inlet gas enters the low-pressure pipeline. Each pipeline is controlled separately without interfering with each other.

[0023] Furthermore, when the pressure transmitter on the high-pressure wellhead gas inlet pipeline or the low-pressure wellhead gas inlet pipeline detects that the pressure of the wellhead gas inlet pipeline exceeds 10MPa, the second automatic shut-off valve is cut off; when the pressure is lower than 10MPa, the second automatic shut-off valve is automatically opened to prevent high-pressure gas exceeding 10MPa from entering the high-pressure collecting pipeline.

[0024] When the pressure transmitter on the downstream of the high-pressure pipeline detects that the pressure of the high-pressure pipeline exceeds 4MPa, the second automatic shut-off valve automatically shuts off; when the pressure of the high-pressure pipeline is lower than 4MPa, the second automatic shut-off valve automatically opens. The second pressure regulating valve on the high-pressure pipeline adjusts the pressure after the regulating valve to 3.5~3.8MPa and enters the downstream pipeline.

[0025] One end of the low-pressure pipeline is connected to the low-pressure pipeline, and the other end is connected to the downstream booster pipeline. The pipeline is equipped with an automatic shut-off valve, a pressure regulating valve, a pressure transmitter and a temperature transmitter. When the pressure transmitter on the high-pressure wellhead gas inlet pipeline or the low-pressure wellhead gas inlet pipeline detects that the pressure of the wellhead gas inlet pipeline exceeds 3.5MPa, the first automatic shut-off valve is cut off; when the pressure is lower than 3.5MPa, the first automatic shut-off valve automatically opens to prevent gas exceeding 3.5MPa from entering the low-pressure pipeline. At the same time, the first pressure regulating valve stabilizes the pressure to below 3.5MPa.

[0026] The utility model further relates to a wellhead gas recovery process, comprising the following steps:

[0027] 1) Wellhead gas intake steps: connect different wellhead gas pipelines to the valve group skid, and wellhead gas with pressure higher than or equal to 9±0.5MPa, especially 9MPa, is connected to the high-pressure wellhead gas inlet pipeline respectively, and wellhead gas with pressure lower than 9±0.5MPa, especially 9MPa, is connected to the low-pressure wellhead gas inlet pipeline respectively (wellhead gas pipeline can be connected to the valve group skid with a high-pressure hose);

[0028] 2) First-stage decompression step: The wellhead gas connected to the high-pressure wellhead gas inlet pipeline will enter the check valve and then the automatic three-way valve after being decompressed to 9MPa or lower through the angle valve; the wellhead gas connected to the low-pressure wellhead gas inlet pipeline will directly enter the check valve and then the automatic three-way valve;

[0029] 3) Three-way diversion step: The inlet gas entering the automatic three-way valve is measured by the pressure transmitter to the pressure before the three-way valve. When the pressure is equal to or higher than 4±0.2MPa, especially 4MPa, the wellhead gas will enter the high-pressure pipeline; when the pressure is lower than 4±0.2MPa, especially 4MPa, the wellhead gas will enter the low-pressure pipeline;

[0030] 4) High-pressure heating and pressure regulation step: the inlet gas entering the high-pressure pipeline enters the second automatic shut-off valve. When the second automatic shut-off valve detects that the pressure is higher than 10±0.2MPa, especially 10MPa, it automatically cuts off to protect downstream equipment and pipelines; when the inlet gas passing through the second automatic shut-off valve detects that the outlet temperature is lower than 0°C through the temperature transmitter, the heater is started (preferably, the heating temperature is automatically calculated and determined through the data transmitted by the pressure transmitter and the temperature transmitter on the high-pressure collection pipeline, and is generally heated to above 5°C), the heated wellhead gas enters the second pressure regulating valve, stabilizes the pressure to 3~4MPa (specifically, it can be adjusted according to the pressure of the high-pressure pipeline network) and then enters the downstream pipeline;

[0031] 5) Low-pressure stabilization and pressure-boosting step: The inlet gas entering the low-pressure pipeline enters the first automatic cut-off valve. When the first automatic cut-off valve detects that the pressure is higher than 10±0.2MPa (the device is equipped with a pressure-stabilizing valve, the pressure is set to 9MPa, and the overpressure cut-off pressure is set to 10MPa), it is automatically cut off to protect downstream equipment and pipelines. The wellhead gas passing through the first automatic cut-off valve enters the first pressure regulating valve, stabilizes the pressure to 1~4MPa (adjusted according to the inlet pressure of the booster), and then enters the booster to increase the pressure to the downstream pipeline network;

[0032] 6) Safe release steps: When the natural gas in the wellhead gas inlet pipeline passes through the angle valve, the pressure is reduced to 9MPa or lower. When the pressure exceeds 9.9±0.2MPa, especially 9.9MPa, the safety valve will trip to release the overpressure gas to the vent main pipe; when the pressure of the high-pressure manifold exceeds 4±0.2MPa after pressure regulation, especially 4MPa, the safety valve on the release line of the high-pressure manifold will trip to release the overpressure gas to the vent main pipe; when the pressure of the low-pressure manifold exceeds the set pressure of the booster inlet after pressure regulation, the safety valve on the release line of the low-pressure manifold will trip to release the overpressure gas to the vent main pipe.

[0033] The utility model has the following functions:

[0034] 1) Double pressure reduction, dual control of angle valve and automatic pressure regulating valve, coarse and fine coordination, first adjust the pressure higher than 9MPa to 9MPa through the angle valve, and then stabilize the pressure to 3~4MPa through the automatic pressure regulating valve. The high-pressure wellhead gas directly enters the downstream pipeline network, and the low-pressure wellhead gas enters the downstream booster unit to be boosted to 3~4MPa and enters the downstream pipeline network. This combination can realize the pressure reduction and stabilization function, while improving the product cost performance, and can flexibly adjust the outlet pressure according to the conditions of each wellhead.

[0035] 2) According to the wellhead conditions, the valve group skid can realize the recovery and use of wellhead gas with different pressures from 0 to 35MPa, but considering the well protection, it will start from the pressure above 1.5MPa. Different from the conventional wellhead gas transmission, the inlet of the valve group skid does not need a busbar, and the gas from 1 to 10 wells with different pressures can be directly connected to the valve group skid through a hose, and then transported by the automatic three-way valve at different pressures, and then transported separately after stabilizing the pressure through the automatic pressure regulating valve to achieve the maximum recovery rate.

[0036] 3) Fully automatic pressure and temperature control. According to the wellhead pressure, the valve group skid outlet temperature is detected. When the temperature is lower than 0℃, the heating device is started in stages. The heating device is set to a three-speed heater. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The technical solution of the utility model is further explained below with reference to the accompanying drawings and through specific implementation methods.

[0038] Figure 1 It is a schematic diagram of the process structure of the wellhead gas recovery device described in the utility model.

[0039] Description of reference numerals:

[0040] BV1~BV30: 1st to 30th high-pressure ball valve; JV1~JV4: 1st to 4th angle valve; CV1~CV10: 1st to 10th check valve; TV1~TV10: 1st to 10th automatic three-way valve; XV1 / XV2: 1st / 2nd automatic shut-off valve; PV1 / PV2: 1st / 2nd automatic pressure regulating valve; E01: heater; SV1~SV6: 1st to 6th safety valve; PT1~ PT12: the first to the twelfth pressure transmitters; TT1 / TT2: the first / second temperature transmitters; L1-1~L1-4: the first to the fourth low-pressure wellhead gas inlet pipelines; L1-5~L1-10: the first to the sixth high-pressure wellhead gas inlet pipelines; L6, L7, L8, L9: the first to the fourth overpressure relief pipelines; L2-1~L2-10: the first to the tenth high-pressure pipelines; L3-1~L3-10: the first to the tenth low-pressure pipelines; L10: the high-pressure collecting pipe relief pipeline; L11: the low-pressure collecting pipe relief pipeline; L12: the relief main pipe. DETAILED DESCRIPTION

[0041] The present invention will be further described below with reference to the accompanying drawings.

[0042] like Figure 1 As shown, the utility model wellhead gas recovery valve group skid device includes one or more low-pressure wellhead gas inlet pipelines (first to sixth low-pressure wellhead gas inlet pipelines L1-5~L1-10), one or more high-pressure wellhead gas inlet pipelines (first to fourth high-pressure wellhead gas inlet pipelines L1-1~L1-4), more than two high-pressure pipelines (first to tenth high-pressure pipelines L2-1~L2-10), more than two low-pressure pipelines (first to tenth low-pressure pipelines L3-1~L3-10), a high-pressure aggregation pipeline L4, a low-pressure aggregation pipeline L5, one or more overpressure relief pipelines (first to fourth overpressure relief pipelines L6, L7, L8, L9), a relief main pipe L12, a high-pressure aggregation pipe relief pipeline L10, and a low-pressure aggregation pipe relief pipeline L11.

[0043] Among them, one end of each high-pressure wellhead gas inlet pipeline (L1-1~L1-4) is connected to a high-pressure wellhead (for example, the pressure is equal to or exceeds 9±0.5MPa, especially 9MPa), and the other end is connected to a low-pressure pipeline (the first to fourth low-pressure pipelines L3-1~L3-4) and a high-pressure pipeline (the first to fourth high-pressure pipelines L2-1~L2-4) through a three-way valve (the first to fourth three-way valves TV1~TV4).

[0044] One end of each low-pressure wellhead gas inlet pipeline (L1-5~L1-10) is connected to a low-pressure wellhead (for example, the pressure is lower than 9±0.5MPa, especially 9MPa), and the other end is connected to a low-pressure pipeline (the fifth to the tenth low-pressure pipeline L3-5~L3-10) and a high-pressure pipeline (the fifth to the tenth high-pressure pipeline L2-5~L2-10) through a three-way valve (the fifth to the thirteenth way valve TV5~TV10).

[0045] Each high-pressure wellhead gas inlet pipeline (L1-1~L1-4) is provided with high-pressure valves (preferably 35MPa high-pressure ball valves, the first to fourth ball valves BV1-BV4), angle valves (the first to fourth angle valves JV1-JV4), check valves (the first to fourth check valves CV1-CV4), and pressure transmitters (the first to fourth pressure transmitters PT1-PT4) in sequence along the gas inlet direction.

[0046] Each low-pressure wellhead gas inlet pipeline (L1-5~L1-10) is equipped with a high-pressure valve (preferably a 35MPa high-pressure ball valve, the fifth to tenth ball valves BV5-BV10), a check valve (the fifth to tenth check valves CV5-CV10), and a pressure transmitter (the fifth to tenth pressure transmitters PT5-PT10) in sequence along the gas inlet direction.

[0047] All high-pressure pipelines (L2-1~L2-10) are connected to the high-pressure pipeline L4 through high-pressure valves (preferably 35MPa high-pressure ball valves, the eleventh to twentieth ball valves BV11-BV20), and all low-pressure pipelines (L3-1~L3-10) are connected to the low-pressure pipeline L5 through high-pressure valves (preferably 35MPa high-pressure ball valves, the twenty-first to thirtieth ball valves BV21-BV30).

[0048] An overpressure relief pipeline (the first to tenth overpressure relief pipelines L6, L7, L8, L9) is led out between the check valve and the three-way valve of each high-pressure wellhead gas inlet pipeline L3-1~L3-4. Each overpressure relief pipeline is provided with a safety valve (the first to fourth safety valves SV1-SV4) and merges into the relief main pipe L12.

[0049] The high-pressure collecting pipeline L4 leads to a high-pressure collecting pipe release pipeline L10 to the release main pipe L12. A safety valve (fifth safety valve SV5) is provided on the high-pressure collecting pipe release pipeline.

[0050] The low-pressure collecting pipeline L5 leads to a low-pressure collecting pipe release pipeline L11 to the release main pipe L12. A safety valve (the sixth safety valve SV6) is provided on the low-pressure collecting pipe release pipeline.

[0051] The first automatic shut-off valve XV1, the first automatic pressure regulating valve PV1, the eleventh pressure transmitter PT11, and the first temperature transmitter TT1 are sequentially arranged downstream of the low-pressure pipeline at the connection point between the low-pressure pipeline and the low-pressure pipeline.

[0052] A second automatic shut-off valve XV2, a heater E01, a second automatic pressure regulating valve PV2, a twelfth pressure transmitter PT12, and a second temperature transmitter TT2 are provided in sequence downstream of the high-pressure pipeline at the connection point between the high-pressure pipeline and the high-pressure collecting pipeline.

[0053] Wellhead gas inlet pipelines L1-1~L1-10, for example, can be provided with 10 pipelines, one end of the pipeline is connected to each wellhead through a hose, the specific number of which is connected according to the number of wellheads, and a maximum of 10 wellheads can be connected, and the other end is connected to the high-pressure pipeline and the low-pressure pipeline. Wellhead gas with a pressure exceeding 9MPa is connected to the high-pressure wellhead gas inlet pipelines L1-1~L1-4; wellhead gas with a pressure not exceeding 9MPa is connected to the low-pressure wellhead gas inlet pipelines L1-5~L1-10. The first to tenth high-pressure ball valves BV1~BV10, the first to fourth angle valves JV1~JV4, the first to tenth check valves CV1~CV10, the first to tenth automatic three-way valves TV1~TV10 and the first to tenth pressure transmitters PT1~PT10 are arranged on the pipeline. When the pressure transmitter detects that the pipeline pressure is greater than or equal to 4MPa, the inlet gas enters the high-pressure pipeline L2-1~L2-10; when the pressure transmitter detects that the pipeline pressure is less than 4MPa, the inlet gas enters the low-pressure pipeline L3-1~L3-10. Each pipeline is controlled separately without interfering with each other.

[0054] High-pressure pipelines L2-1~L2-10, for example, are provided with 10 pipelines, one end of the pipeline is connected to the first to tenth automatic three-way valves TV1~TV10, and the other end is connected to the high-pressure collection pipeline. A high-pressure ball valve is installed on the pipeline to ensure the safety of the pipeline even if the valve in front of the pipeline leaks or fails.

[0055] The low-pressure pipelines L3-1~L3-10, for example, are provided with 10 pipelines, one end of the pipeline is connected to the first to tenth automatic three-way valves TV1~TV10, and the other end is connected to the low-pressure collecting pipeline. A high-pressure ball valve is installed on the pipeline to ensure the safety of the pipeline even if the valve in front of the pipeline leaks or fails.

[0056] The high-pressure collection pipeline L4 is connected to the first to tenth high-pressure pipelines L2-1~L2-10 at one end and to the downstream pipeline at the other end. An automatic shut-off valve, a heater, a pressure regulating valve, a pressure transmitter and a temperature transmitter are installed on the pipeline. When the pressure of the wellhead gas inlet pipeline PT1~PT10 is detected to exceed 10MPa, the second automatic shut-off valve XV2 is cut off; when the pressure is lower than 10MPa, the second automatic shut-off valve XV2 automatically opens to prevent high-pressure gas exceeding 10MPa from entering L4. When the pressure PT12 of the high-pressure collection pipeline is detected to exceed 4MPa, the second automatic shut-off valve XV2 is automatically cut off; when the PT12 pressure is lower than 4MPa, the second automatic shut-off valve XV2 is automatically opened. The second pressure regulating valve PV2 adjusts the pressure after the regulating valve to 3.5~3.8MPa and enters the downstream pipeline. Heater E01 is a three-speed heater. Through the control program setting, the first-speed heater is started when the temperature is lower than 0℃, the first and second-speed heaters are started when the temperature is lower than -5℃, the first, second and third-speed heaters are started when the temperature is lower than -10℃, and the heater stops heating when the temperature is higher than 5℃.

[0057] The low-pressure collection pipeline L5 is connected to the first to tenth low-pressure pipelines L3-1~L3-10 at one end and to the downstream booster pipeline at the other end. Automatic shut-off valves, pressure regulating valves, pressure transmitters and temperature transmitters are installed on the pipeline. When the wellhead gas inlet pipeline pressure PT1~PT10 is detected to exceed 3.5MPa, the first automatic shut-off valve XV1 is cut off; when the pressure is lower than 3.5MPa, the first automatic shut-off valve XV1 automatically opens to prevent gas exceeding 3.5MPa from entering L5. At the same time, the first pressure regulating valve PV1 stabilizes the pressure to below 3.5MPa.

[0058] The safety release pipeline includes L6~L12. In a preferred embodiment, one end of the L6 pipeline is connected to L1-4 and the other end is connected to L12 to prevent the pressure of the L1-4 pipeline from exceeding 9.9MPa; one end of the L7 pipeline is connected to L1-3 and the other end is connected to L12 to prevent the pressure of the L1-3 pipeline from exceeding 9.9MPa; one end of the L8 pipeline is connected to L1-2 and the other end is connected to L12 to prevent the pressure of the L1-2 pipeline from exceeding 9.9MPa; one end of the L9 pipeline is connected to L1-1 and the other end is connected to L12 to prevent the pressure of the L1-1 pipeline from exceeding 9.9MPa; one end of the L10 pipeline is connected to L4 and the other end is connected to L12 to prevent the pressure of the L4 pipeline from exceeding 4MPa after pressure regulation; one end of the L11 pipeline is connected to L5 and the other end is connected to L12 to prevent the pressure of the L5 pipeline from exceeding 3.8MPa.

[0059] In the present application, all shut-off valves are preferably automatic shut-off valves, which fully automatically realize the opening and closing functions of each pipeline, and realize one-button start and stop of wellhead gas intake, diversion, and pressure regulation.

[0060] The utility model further provides a wellhead gas recovery process using the wellhead gas recovery valve group skid device, comprising the following steps:

[0061] 1) Wellhead gas intake steps: connect different wellhead gas pipelines to the valve group skid, connect wellhead gas with pressure higher than or equal to 9MPa to high-pressure wellhead gas inlet pipelines L1-1 to L1-4 respectively, and connect wellhead gas with pressure lower than 9MPa to low-pressure wellhead gas inlet pipelines L1-5 to L1-10 respectively (wellhead gas pipelines can be connected to the valve group skid with high-pressure hoses);

[0062] 2) First-stage decompression step: The wellhead gas connected to the high-pressure wellhead gas inlet pipelines L1-1~L1-4 will be decompressed to 9MPa or lower through angle valves JV1~JV4 and then enter the check valves CV1~CV4, and then enter the automatic three-way valves TV1~TV4; the wellhead gas connected to the low-pressure wellhead gas inlet pipelines L1-5~L1-10 will directly enter the check valves CV5~CV10, and then enter the automatic three-way valves TV5~TV10;

[0063] 3) Three-way diversion step: The inlet gas entering the automatic three-way valve TV1~TV10 will be measured by the pressure transmitter to measure the pressure before the three-way valve. When the pressure is equal to or higher than 4MPa, the wellhead gas will enter the high-pressure pipeline L2-1~L2-10; when the pressure is lower than 4MPa, the wellhead gas will enter the low-pressure pipeline L3-1~L3-10;

[0064] 4) High-pressure heating and pressure regulation step: the inlet gas entering the high-pressure pipeline enters the second automatic shut-off valve XV2. When the second automatic shut-off valve XV2 detects that the pressure is higher than 10MPa, it is automatically cut off to protect the downstream equipment and pipelines; when the inlet gas passing through the second automatic shut-off valve XV2 detects that the outlet temperature is lower than 0°C through the temperature transmitter, the heater E01 is started (preferably, the heating temperature is automatically calculated and determined through the data transmitted by the pressure transmitter and the temperature transmitter on the high-pressure collection pipeline, and is generally heated to above 5°C), the heated wellhead gas enters the second pressure regulating valve PV2, stabilizes the pressure to 3~4MPa (specific pressure can be adjusted according to the high-pressure pipeline network), and then enters the downstream pipeline;

[0065] 5) Low-pressure stabilization and pressure-boosting step: The inlet gas entering the low-pressure pipeline enters the first automatic cut-off valve XV1. When the first automatic cut-off valve XV1 detects that the pressure is higher than 10MPa (the device is equipped with a pressure-stabilizing valve, the pressure is set to 9MPa, and the overpressure cut-off pressure is set to 10MPa), it is automatically cut off to protect downstream equipment and pipelines. The wellhead gas passing through the first automatic cut-off valve XV1 enters the first pressure regulating valve, stabilizes the pressure to 1~4MPa (adjusted according to the inlet pressure of the booster), and then enters the booster to increase the pressure to the downstream pipeline network;

[0066] 6) Safety release steps: When the natural gas in the wellhead gas inlet pipeline passes through the angle valves JV1~JV4, the pressure is reduced to 9MPa or lower. When the pressure exceeds 9.9MPa, the safety valve will trip and release the overpressure gas to the vent main pipe; when the pressure of the high-pressure manifold exceeds 4MPa after pressure regulation, the safety valve SV5 on the high-pressure manifold release pipeline will trip and release the overpressure gas to the vent main pipe 12; when the pressure of the low-pressure manifold exceeds the set pressure of the booster inlet after pressure regulation, the safety valve SV6 on the low-pressure manifold release pipeline will trip and release the overpressure gas to the vent main pipe L12.

[0067] In the above process, double pressure reduction is implemented, and the angle valve and the automatic pressure regulating valve are dually controlled, and the coarse and fine coordination is first used to adjust the pressure higher than 9MPa to 9MPa through the angle valve, and then the pressure is stabilized to 3~4MPa through the automatic pressure regulating valve. The high-pressure wellhead gas directly enters the downstream pipeline network, and the low-pressure wellhead gas enters the downstream booster unit and is boosted to 3~4MPa and enters the downstream pipeline network. This combination can not only realize the pressure reduction and stabilization function, but also improve the product cost performance, and can flexibly adjust the outlet pressure according to the conditions of each wellhead. In high-pressure pressure regulation, when the pressure regulation ratio is ≥5, two-stage pressure regulation is usually adopted. Due to the relatively high pressure, imported high-pressure pressure regulators are required, which are expensive. In this utility model, only angle valves are used to regulate the pressure in the first stage. Although the accuracy is lower than that of the pressure regulator, due to the use of high-precision pressure regulators in the second stage, stable pressure output can be guaranteed while reducing equipment investment.

[0068] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention of the utility model.

Claims

1. A valve group skid device suitable for wellhead gas recovery, characterized in that: It includes one or more high-pressure wellhead gas inlet pipelines, one or more low-pressure wellhead gas inlet pipelines, more than two high-pressure pipelines, more than two low-pressure pipelines, a high-pressure aggregation pipeline, a low-pressure aggregation pipeline, one or more overpressure relief pipelines, a relief main pipe, a high-pressure aggregation pipeline relief pipeline, and a low-pressure aggregation pipeline relief pipeline. Among them, one end of each high-pressure wellhead gas inlet pipeline is connected to the high-pressure wellhead, and the other end is connected to another low-pressure pipeline and another high-pressure pipeline through a three-way valve. One end of each low-pressure wellhead gas inlet pipeline is connected to a low-pressure wellhead, and the other end is connected to a low-pressure pipeline and a high-pressure pipeline through a three-way valve. Each high-pressure wellhead gas inlet pipeline is equipped with a high-pressure valve, angle valve, check valve, and pressure transmitter in sequence along the gas inlet direction. Each low-pressure wellhead gas inlet pipeline is equipped with a high-pressure valve, a check valve, and a pressure transmitter in sequence along the gas inlet direction. All high-pressure pipelines are connected to the high-pressure pipeline through high-pressure valves, and all low-pressure pipelines are connected to the low-pressure pipeline through high-pressure valves. An overpressure relief pipeline is drawn out between the check valve and the three-way valve of each high-pressure wellhead gas inlet pipeline. Each overpressure relief pipeline is equipped with a safety valve and merges into the relief main pipe. The high-pressure collection pipeline leads to a high-pressure collection pipe release pipeline to the release main pipe. A safety valve is installed on the high-pressure collection pipe release pipeline. The low-pressure collection pipeline leads to a low-pressure collection pipe release pipeline to the release main pipe. A safety valve is installed on the low-pressure collection pipe release pipeline. A first cut-off valve and a first automatic pressure regulating valve are provided in sequence downstream of the low-pressure pipeline at the connection point between the low-pressure pipeline and the low-pressure pipeline. A second shut-off valve, a heater, and a second automatic pressure regulating valve are sequentially arranged downstream of the high-pressure collecting pipeline at the connection point between the high-pressure pipeline and the high-pressure collecting pipeline.

2. The valve group skid device according to claim 1, characterized in that: A pressure transmitter and / or a temperature transmitter is also provided downstream of the low-pressure collecting pipeline at the connection point between the low-pressure pipeline and the low-pressure collecting pipeline and after the first automatic pressure regulating valve.

3. The valve group skid device according to claim 1 or 2, characterized in that: A pressure transmitter and / or a temperature transmitter is also provided downstream of the high-pressure collecting pipeline at the connection point between the high-pressure pipeline and the high-pressure collecting pipeline and after the second automatic pressure regulating valve.

4. The valve group skid device according to claim 1, characterized in that: The heater is a three-speed heater. Through the control program setting, when the temperature is lower than 0℃, the first-speed heater is started; when the temperature is lower than -5℃, the first and second-speed heaters are started; when the temperature is lower than -10℃, the first, second and third-speed heaters are started; when the temperature is higher than 5℃, the heater stops heating.

5. The valve group skid device according to claim 1, characterized in that: All shut-off valves are automatic shut-off valves.

6. The valve group skid device according to claim 1, characterized in that: Wellhead gas with a pressure exceeding 9MPa is connected to the high-pressure wellhead gas inlet pipeline; wellhead gas with a pressure not exceeding 9MPa is connected to the low-pressure wellhead gas inlet pipeline.

7. The valve group skid device according to claim 1, characterized in that: Each pipeline is controlled independently without interfering with each other.

Images