Continuous gas lift method and system based on high-pressure and low-pressure distribution system

Abstract

The invention discloses a continuous gas lift method and system based on a high-pressure and low-pressure distribution system, and the method comprises the steps: building a high-pressure gathering and transportation pipe network and a low-pressure gathering and transportation pipe network respectively, and forming the high-pressure and low-pressure distribution system; high-pressure and low-pressure gathering and transportation pipe networks are connected through a continuous gas lift system; the normal productivity of the gas-lift gas well and the maximum gas conveying amount of the gas-lift gas are determined according to the early-stage production data; a production instruction is input, and the production instruction comprises the set value range of the gas lift gas conveying amount, the wellhead gas production amount and the gas well real gas production amount; judging whether the production instruction is in a preset reasonable range or not by combining the normal productivity and the maximum gas output, and if yes, adjusting the gas lift gas output, the wellhead gas output and the real gas output of the gas well in the production process according to the judgment result; otherwise, re-inputting or automatically generating the production instruction; and continuously monitoring, adjusting and updating production data. The gas lift flow can be reasonably adjusted, continuous gas lift of the gas well is effectively achieved, and the good effects of guaranteeing stable production of the gas well and improving the liquid carrying capacity and the recovery rate of the low-pressure gas well are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of unconventional oil and gas development, and in particular to a continuous gas lift method and system based on a high and low pressure distribution system. Background Art

[0002] my country has abundant unconventional oil and gas resources, including tight gas and shale gas. With the continuous advancement of unconventional oil and gas development technology, it has entered a stage of rapid production construction and is the main area for increasing natural gas reserves and production in the future. Taking shale gas as an example, large-scale hydraulic fracturing is usually adopted for development. These fracturing fluids will gradually flow back in subsequent production. Although most of the fracturing fluids will flow back in the early stage of production, there will still be a lot of fracturing fluids flowing back in the later stage of production. As the production capacity of gas wells decreases, most gas wells are often unable to carry liquids effectively, which will have a serious impact on the production effect of gas wells. These problems are important issues that affect production in both tight gas wells and conventional gas wells.

[0003] Drainage and gas production measures are currently the main technical means to ensure the normal liquid carrying of gas wells. Gas lift is one of the commonly used drainage and gas production measures. It is to inject high-pressure natural gas into the well, use the gas lift valve to gradually remove the accumulated liquid near the wellbore and the bottom of the well, and restore the production of the gas well. Compared with foam drainage and gas production, plunger drainage and gas production, electric submersible pump drainage and gas production, it has strong adaptability to different well trajectories, well depths, sand production, scaling, corrosive media, drainage volume, and changes in gas-liquid ratio. It can be repeatedly started, the equipment is simple, and the economic benefits are high. Among them, continuous gas lift is one of the effective methods to ensure the stable production of gas wells.

[0004] At present, there are few inventions for continuous gas lift methods, and there is only a method of continuous gas lift between high-pressure gas source wells to drain water and produce gas. It mainly uses the high-pressure gas of the high-pressure gas wells of the same gas gathering station as the gas source to achieve continuous gas lift of the low-pressure weak-spouting water-producing gas wells in the station. This method has certain limitations. If there are no high- and low-pressure gas wells in the same field station, it cannot be carried out. Therefore, it is not practical for large-scale development, multi-well field platforms, and uneven production capacity distribution of each platform. At the same time, the lack of flow control cannot effectively guarantee efficient gas lift.

[0005] At present, a large number of high-pressure gas wells (gathering and transportation pressure is usually greater than 5MPa) and low-pressure gas wells (gathering and transportation pressure is usually less than 2MPa) coexist, and there are conditions to establish a ground pipeline system for separate gathering and transportation (or adopt a high-pressure gathering and transportation system and low-pressure gas well wellhead pressurization, similar to a short-distance low-pressure gathering and transportation system). At the same time, it can also be directly connected to the regional gas gathering and transportation pipeline network to ensure sufficient gas supply.

[0006] Therefore, in view of the current problems of a large number of gas wells being put into production, uneven distribution of high-yield and low-yield gas wells, and difficulty in normal production of low-pressure gas wells, it is necessary to develop a method that can effectively mobilize high-pressure gas sources in a large area and stably assist low-pressure gas wells in continuous and efficient production. Summary of the invention

[0007] In view of the problems that existing drainage and gas production measures will inject chemical substances, have high costs, and intermittent well opening and closing may affect gas wells, the present invention proposes a continuous gas lift method and system based on high- and low-pressure distribution systems on the basis of separate collection and transportation of high-pressure gas and low-pressure gas on the ground. The high-pressure gas source is sufficient, no chemical substances are injected, the operating cost is low, the gas lift flow rate can be reasonably adjusted, and continuous gas lift of gas wells can be effectively realized, which has a good effect on ensuring stable production of gas wells and improving the liquid carrying capacity and recovery rate of low-pressure gas wells.

[0008] The technical solution adopted by the present invention is as follows:

[0009] A continuous gas lift method based on a high and low pressure distribution system comprises the following steps:

[0010] Step 1: Establish high-pressure and low-pressure gathering and transmission pipeline networks respectively to form high-pressure and low-pressure distribution and transmission systems;

[0011] Step 2: Connect high and low pressure gathering and transportation pipelines through a continuous gas lift system;

[0012] Step 3: Determine the normal production capacity Q of the gas-lifted well using previous production data 气 Maximum gas delivery volume Q of gas lift 举 ;

[0013] Step 4: Input production instructions, including the gas lift gas delivery volume setting value range Q 举-设 , Wellhead gas production setting value range Q 产-设 The setting value range of the actual gas production of the gas well Q 实-设 ;

[0014] Step 5: Combine the normal capacity Q 气 and maximum gas flow rate Q 举 , determine whether the production instruction is within a preset reasonable range, if so, execute the next step; otherwise, return to the previous step and re-enter or automatically generate the production instruction;

[0015] Step 6: Monitor the production process. If the actual value of the gas lift gas input M1 is lower or higher than the set value range Q 举-设 , then the continuous gas lift system is adjusted to increase or decrease the gas lift gas input;

[0016] Step 7: Monitor the production process. If the actual value of the wellhead gas production M2 is lower or higher than the set value range Q 产-设, then the continuous gas lift system is adjusted to increase or decrease the wellhead gas production;

[0017] Step 8: Monitor the production process. If the actual value of the actual gas production of the gas well M2-M1 is lower or higher than the set value range Q 实-设 , then the actual gas production of the gas well is increased or decreased by adjusting the continuous gas lift system;

[0018] Step 9: Maintain normal production according to the adjustment results of steps 6 to 8, continuously monitor and adjust, and update production data.

[0019] Furthermore, in step 6, if the actual value M1 of the gas lift gas input is lower or higher than the set value range Q 举-设 , the gas lift gas input amount is increased or decreased by adjusting the throttle valve opening degree of the continuous gas lift system.

[0020] Furthermore, in step 7, if the actual value M2 of the wellhead gas production is lower or higher than the set value range Q 产-设 , the wellhead gas production is increased or decreased by adjusting the opening degree of the throttle valve of the continuous gas lift system.

[0021] Furthermore, in step 8, if the actual value M2-M1 of the actual gas production of the gas well is lower or higher than the set value range Q 实-设 , the actual gas production of the gas well can be increased or decreased by adjusting the opening degree of the throttle valve of the continuous gas lift system.

[0022] A continuous gas lift system based on a high- and low-pressure distribution system comprises an inlet control valve, a first flow meter, a first bypass valve, a rear-end control valve, a first throttle valve, a gas well and a production system, a second throttle valve, a second flow meter, a second bypass valve and a boosting system, wherein the inlet end of the inlet control valve is connected to a high-pressure gathering and transportation pipeline network, and the outlet end is connected to the inlet end of the rear-end control valve through the first flow meter and the bypass valve, respectively; the outlet end of the rear-end control valve is connected to the inlet end of the gas well and the production system through the first throttle valve, the outlet end of the gas well and the production system is connected to the second flow meter and the second bypass valve, respectively, through the second throttle valve; the outlet end of the second bypass valve is connected to a low-pressure gathering and transportation pipeline network and is connected to a high-pressure gathering and transportation pipeline network through the boosting system.

[0023] Furthermore, during the production monitoring process, if the actual value M1 of the gas lift gas input is less than the set value range Q 举-设 , the first throttle valve of the continuous gas lift system is adjusted to increase the opening degree to increase the gas lift gas input; otherwise, the opening degree is reduced to reduce the gas lift gas input.

[0024] Furthermore, during the production monitoring process, if the actual value M2 of the wellhead gas production is less than the set value range Q 产-设, then adjust the second throttle valve of the continuous gas lift system to increase the opening degree to increase the wellhead gas production; otherwise, reduce the opening degree to reduce the wellhead gas production.

[0025] Furthermore, during the production monitoring process, if the actual value of the actual gas production of the gas well M2-M1 is less than or greater than the set value range Q 实-设 , then adjust the opening degree of the first throttle valve and / or the second throttle valve of the continuous gas lift system.

[0026] Furthermore, the high-pressure gathering and transportation pipeline network includes a plurality of high-pressure wells and corresponding high-pressure process stations, and the high-pressure wells and high-pressure process stations can be connected to the regional gathering and transportation pipeline network.

[0027] Furthermore, the low-pressure gathering and transportation pipeline network includes a plurality of low-pressure wells, and the low-pressure wells can be connected to a booster station or a user end.

[0028] The beneficial effects of the present invention are:

[0029] (1) The continuous gas lift method and system of the present invention is based on a system for collecting and transporting high-pressure gas and low-pressure gas on the ground respectively. The high-pressure gas source is sufficient, no chemical substances are injected, the operating cost is low, the gas lift flow rate can be reasonably adjusted, and the continuous gas lift of the gas well can be effectively realized. It has a good effect on ensuring the stable production of the gas well and improving the liquid carrying capacity and recovery rate of the low-pressure gas well.

[0030] (2) The present invention can call upon high-pressure gas sources within a large area to provide sufficient high-pressure gas sources for gas lift, and can also reasonably adjust the gas lift flow rate to ensure continuous and efficient operation of gas lift. The process flow and implementation process are simple, and can effectively realize low-cost continuous gas lift operations in gas wells, thereby ensuring continuous and normal production of gas wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flow chart of the continuous gas lift method according to an embodiment of the present invention.

[0032] Figure 2 Schematic diagram of a high and low pressure distribution system according to an embodiment of the present invention.

[0033] Figure 3 Schematic diagram of a continuous gas lift system according to an embodiment of the present invention.

[0034] Description of the drawings: 1-station control valve, 2-first flow meter, 3-first bypass valve, 4-rear-end control valve, 5-first throttle valve, 6-gas well and production system, 7-second throttle valve, 8-second flow meter, 9-second bypass valve, 10-boosting system, NET1-high-pressure gathering and transportation pipeline network, NET2-low-pressure gathering and transportation pipeline network. DETAILED DESCRIPTION

[0035] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0036] Example 1

[0037] At present, a large number of high-pressure gas wells (gathering and transportation pressure is usually greater than 5MPa) and low-pressure gas wells (gathering and transportation pressure is usually less than 2MPa) coexist, and there are conditions to establish a ground pipeline system for separate gathering and transportation (or adopt a high-pressure gathering and transportation system and low-pressure gas well wellhead pressurization, similar to a short-distance low-pressure gathering and transportation system). At the same time, it can also be directly connected to the regional gas gathering and transportation pipeline network to ensure sufficient gas supply.

[0038] In view of the current problems of a large number of gas wells being put into production, uneven distribution of high-yield and low-yield gas wells, and difficulty in normal production of low-pressure gas wells, this embodiment provides a continuous gas lift method based on a high- and low-pressure distribution system, which can effectively mobilize high-pressure gas sources in a large area and stably assist low-pressure gas wells in continuous and efficient production.

[0039] like Figure 1 As shown, the continuous gas lift method of this embodiment includes the following steps:

[0040] Step 1: Figure 2 As shown, high and low pressure gathering and transportation pipeline networks are established respectively. Specifically, a high pressure gathering and transportation pipeline network NET1 in a large area and a low pressure gathering and transportation pipeline network NET2 in a large area or in a well field can be established, thereby forming a high and low pressure distribution system.

[0041] Step 2: If Figure 3 As shown, the high and low pressure gathering and transportation pipelines are connected through a continuous gas lift system, wherein the continuous gas lift system includes a control valve, a flow meter, a throttle valve, etc.

[0042] Step 3: Determine the normal production capacity Q of the gas-lifted well using previous production data 气 Maximum gas delivery volume Q of gas lift 举 , where the normal capacity Q 气 It can be the average daily production within 10 days when the gas well is in continuous and stable production and the daily gas production variation is less than 10%.

[0043] Step 4: Input production instructions, including the gas lift gas delivery volume setting value range Q 举-设 , Wellhead gas production setting value range Q 产-设 The setting value range of the actual gas production of the gas well Q 实-设, which can be one or more of them.

[0044] Step 5: Combine normal capacity Q 气 and maximum gas flow rate Q 举 , determine whether the production instruction is within the preset reasonable range. If so, execute the next step to automatically adjust and monitor the process; otherwise, return to the previous step and re-enter or automatically generate the production instruction.

[0045] Step 6: Monitor the production process. If the actual value of the gas lift gas input M1 is lower or higher than the set value range Q 举-设 , the continuous gas lift system is adjusted to increase or decrease the gas lift gas input.

[0046] Step 7: Monitor the production process. If the actual value of the wellhead gas production M2 is lower or higher than the set value range Q 产-设 , the continuous gas lift system is adjusted to increase or decrease the wellhead gas production.

[0047] Step 8: Monitor the production process. If the actual value of the actual gas production of the gas well M2-M1 is lower or higher than the set value range Q 实-设 , the continuous gas lift system is adjusted to increase or decrease the actual gas production of the gas well.

[0048] Step 9: Maintain normal production according to the adjustment results of steps 6 to 8, continuously monitor and adjust, and update production data.

[0049] Preferably, in step 6, if the actual value M1 of the gas lift gas input is lower or higher than the set value range Q 举-设 , the gas lift gas input can be increased or decreased by adjusting the throttle valve opening degree of the continuous gas lift system.

[0050] Preferably, in step 7, if the actual value M2 of the wellhead gas production is lower than or higher than the set value range Q 产-设 , the wellhead gas production can be increased or decreased by adjusting the throttle valve opening degree of the continuous gas lift system.

[0051] Preferably, in step 8, if the actual value M2-M1 of the actual gas production of the gas well is lower or higher than the set value range Q 实-设 , the actual gas production of the gas well can be increased or decreased by adjusting the opening degree of the throttle valve of the continuous gas lift system.

[0052] The continuous gas lift method of this embodiment can call on high-pressure gas sources within a large area to provide sufficient high-pressure gas sources for gas lift, and can also reasonably adjust the gas lift flow rate to ensure efficient operation of continuous gas lift. The process flow and implementation process are simple, and can effectively realize low-cost continuous gas lift operations in gas wells, ensuring continuous and normal production of gas wells.

[0053] Example 2

[0054] This embodiment is based on embodiment 1:

[0055] This embodiment provides a continuous gas lift system based on high and low pressure distribution systems, such as Figure 3 As shown, it includes an inlet control valve 1, a first flow meter 2, a first bypass valve 3, a rear-end control valve 4, a first throttle valve 5, a gas well and a production system 6, a second throttle valve 7, a second flow meter 8, a second bypass valve 9 and a boosting system 10. The air inlet end of the inlet control valve 1 is connected to the high-pressure gathering and transportation pipeline network NET1, and the air outlet end is connected to the air inlet end of the rear-end control valve 4 through the first flow meter 2 and the bypass valve 3 respectively, the air outlet end of the rear-end control valve 4 is connected to the air inlet end of the gas well and the production system 6 through the first throttle valve 5, the air outlet end of the gas well and the production system 6 is connected to the second flow meter 8 and the second bypass valve 9 respectively through the second throttle valve 7, and the air outlet end of the second bypass valve 9 is connected to the low-pressure gathering and transportation pipeline network NET2 and connected to the high-pressure gathering and transportation pipeline network NET1 through the boosting system 10.

[0056] Preferably, during the monitoring process, if the actual value M1 of the gas lift gas input is less than the set value range Q 举-设 , then adjust the first throttle valve 5 of the continuous gas lift system to increase the opening degree to increase the gas lift gas input; otherwise, reduce the opening degree to reduce the gas lift gas input.

[0057] Preferably, during the production monitoring process, if the actual value M2 of the wellhead gas production is less than the set value range Q 产-设 , then adjust the second throttle valve 7 of the continuous gas lift system to increase the opening degree to increase the wellhead gas production; otherwise, reduce the opening degree to reduce the wellhead gas production.

[0058] Preferably, during the production monitoring process, if the actual value M2-M1 of the actual gas production of the gas well is less than or greater than the set value range Q 实-设 , then adjust the opening degree of the first throttle valve 5 and / or the second throttle valve 7 of the continuous gas lift system.

[0059] like Figure 2 As shown, the high-pressure gathering and transportation pipeline network NET1 includes several high-pressure wells and corresponding high-pressure process stations, which can be connected to the regional gathering and transportation pipeline network; the low-pressure gathering and transportation pipeline network NET2 includes several low-pressure wells, which can be connected to the booster station or the user end.

[0060] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity of description, they are expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the order of the actions described, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

Claims

1. A continuous gas lift method based on a high and low pressure distribution system, characterized in that: The following steps are involved: Step 1: Establish high-pressure and low-pressure gathering and transmission pipeline networks respectively to form high-pressure and low-pressure distribution and transmission systems; Step 2: Connect high and low pressure gathering and transportation pipelines through a continuous gas lift system; Step 3: Determine the normal production capacity Q of the gas-lifted well using previous production data 气 Maximum gas delivery volume Q of gas lift 举 ; Step 4: Input production instructions, including the gas lift gas delivery volume setting value range Q 举-设 , Wellhead gas production setting value range Q 产-设 The setting value range of the actual gas production of the gas well Q 实-设 ; Step 5: Combine the normal capacity Q 气 and maximum gas flow rate Q 举 , determine whether the production instruction is within a preset reasonable range, if so, execute the next step; Otherwise, return to the previous step and re-enter or automatically generate production instructions; Step 6: Monitor the production process. If the actual value of the gas lift gas input M1 is lower or higher than the set value range Q 举-设 , then the continuous gas lift system is adjusted to increase or decrease the gas lift gas input; Step 7: Monitor the production process. If the actual value of the wellhead gas production M2 is lower or higher than the set value range Q 产-设 , then the continuous gas lift system is adjusted to increase or decrease the wellhead gas production; Step 8: Monitor the production process. If the actual value of the actual gas production of the gas well M2-M1 is lower or higher than the set value range Q 实-设 , then the actual gas production of the gas well is increased or decreased by adjusting the continuous gas lift system; Step 9: Maintain normal production according to the adjustment results of steps 6 to 8, continuously monitor and adjust, and update production data.

2. The continuous gas lift method based on high and low pressure distribution system according to claim 1 is characterized in that: In step 6, if the actual value M1 of the gas lift gas input is lower or higher than the set value range Q 举-设 , the gas lift gas input amount is increased or decreased by adjusting the throttle valve opening degree of the continuous gas lift system.

3. The continuous gas lift method based on high and low pressure distribution system according to claim 1 is characterized in that: In step 7, if the actual value of the wellhead gas production M2 is lower or higher than the set value range Q 产-设 , the wellhead gas production is increased or decreased by adjusting the opening degree of the throttle valve of the continuous gas lift system.

4. The continuous gas lift method based on high and low pressure distribution system according to claim 1 is characterized in that: In step 8, if the actual value of the actual gas production of the gas well M2-M1 is lower or higher than the set value range Q 实-设 , the actual gas production of the gas well can be increased or decreased by adjusting the opening degree of the throttle valve of the continuous gas lift system.

5. A continuous gas lift system based on high and low pressure distribution systems, applied to the continuous gas lift method according to claim 1, characterized in that: The continuous gas lift system comprises an inlet control valve (1), a first flow meter (2), a first bypass valve (3), a rear-end control valve (4), a first throttle valve (5), a gas well and a production system (6), a second throttle valve (7), a second flow meter (8), a second bypass valve (9) and a boosting system (10); the inlet end of the inlet control valve (1) is connected to a high-pressure gathering and transportation network (NET1), and the outlet end is connected to the inlet end of the rear-end control valve (4) through the first flow meter (2) and the bypass valve (3), respectively; the outlet end of the rear-end control valve (4) is connected to the inlet end of the gas well and the production system (6) through the first throttle valve (5), the outlet end of the gas well and the production system (6) is connected to the second flow meter (8) and the second bypass valve (9) through the second throttle valve (7), respectively; the outlet end of the second bypass valve (9) is connected to a low-pressure gathering and transportation network (NET2) and is connected to a high-pressure gathering and transportation network (NET1) through the boosting system (10).

6. The continuous gas lift system based on high and low pressure distribution system according to claim 5 is characterized in that: During the production monitoring process, if the actual value of the gas lift gas input M1 is less than the set value range Q 举-设 , adjusting the first throttle valve (5) of the continuous gas lift system to increase the opening degree so as to increase the gas lift gas input; On the contrary, the opening degree is reduced to reduce the gas lift gas input.

7. The continuous gas lift system based on high and low pressure distribution system according to claim 5, characterized in that: During the production monitoring process, if the actual value of the wellhead gas production M2 is less than the set value range Q 产-设 , the second throttle valve (7) of the continuous gas lift system is adjusted to increase the opening degree to increase the wellhead gas production; otherwise, the opening degree is reduced to reduce the wellhead gas production.

8. The continuous gas lift system based on high and low pressure distribution system according to claim 5, characterized in that: During the production monitoring process, if the actual value of the actual gas production of the gas well M2-M1 is less than or greater than the set value range Q 实-设 , then adjust the opening degree of the first throttle valve (5) and / or the second throttle valve (7) of the continuous gas lift system.

9. The continuous gas lift system based on high and low pressure distribution system according to any one of claims 5 to 8, characterized in that: The high-pressure gathering and transportation pipeline network (NET1) includes a number of high-pressure wells and corresponding high-pressure process stations, and the high-pressure wells and high-pressure process stations can be connected to the regional gathering and transportation pipeline network.

10. The continuous gas lift system based on high and low pressure distribution system according to any one of claims 5 to 8, characterized in that: The low-pressure gathering and transmission pipeline network (NET2) includes a plurality of low-pressure wells, and the low-pressure wells can be connected to a booster station or a user end.

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