Gas lift pressurization mixed transportation and CNG recovery system

Abstract

The invention relates to the technical field of natural gas extraction, and discloses a gas lift pressurization mixed transportation and CNG recovery system which comprises an integrated compressor skid, a high-pressure dehydration skid and a gas generator set, the integrated compressor skid is provided with a first inlet, a first outlet, a second outlet and a third outlet, the first inlet is communicated with an external transportation pipeline through a gas inlet pipeline, and the second outlet is communicated with a second transportation pipeline through a gas outlet pipeline; the first outlet is communicated with the output pipeline through a pressurization mixed transportation pipeline, the pressurization mixed transportation pipeline is located at the downstream of the gas inlet pipeline, the second outlet is communicated with the output pipeline through a gas lift pipeline, and the gas lift pipeline is located at the upstream of the gas inlet pipeline; the high-pressure dewatering skid is provided with a recycled moisture inlet and a dewatering and sewage discharging outlet, the recycled moisture inlet is communicated with the third outlet through a CNG recycled moisture pipeline, and the dewatering and sewage discharging outlet is communicated with the gas inlet pipeline through a dewatering and sewage discharging mixed conveying pipeline; the gas generator set is electrically connected to the integrated compressor sledge and the high-pressure dewatering sledge so as to provide electric energy for the integrated compressor sledge and the high-pressure dewatering sledge.

Description

Technical Field

[0001] The present application belongs to the technical field of natural gas extraction, and specifically relates to a gas lift, pressurized, mixed transmission and CNG recovery system. Background Art

[0002] Through technological innovation and optimization, natural gas has provided key support for energy conservation, emission reduction and the realization of the "dual carbon" goals, making natural gas one of the country's important strategic reserves and clean energy sources, and is widely used in all walks of life. With the increasing demand for natural gas, on the one hand, it has brought unprecedented opportunities for the development of the natural gas industry. On the other hand, as gas wells are continuously exploited, reserves are decreasing, especially in the middle and late stages of gas well exploitation. Improving gas well recovery rates and waste well utilization rates have become an important issue in the natural gas exploitation process.

[0003] In the traditional wellhead mining process, most of them adopt direct natural drainage in the early stage and pressurized gathering and transportation in the later stage. For gas wells with liquid accumulation at the bottom of the well, intermittent high-pressure gas lift measures are adopted, which makes it impossible to ensure continuous production; and most of the equipment supporting the process has only one function, with poor applicability and imperfect process performance, which makes the actual operation on site complicated, the pressure of abandoned wells is high, and the investment and operation and maintenance costs are high; some gas wells are flooded and blocked by water, which seriously affects the overall recovery rate, seriously wastes resources, and has no obvious production increase effect, especially in most marginal wells and scattered wells, the return on investment is extremely low. Summary of the invention

[0004] The present application provides a gas lift pressurized mixed transmission and CNG recovery system to increase the return on investment of natural gas extraction.

[0005] The technical solution adopted in this application is:

[0006] A gas lift pressurized mixed transmission and CNG recovery system, comprising:

[0007] An integrated compressor skid, which is used for pressurizing, gas-liquid separation and gas lifting of natural gas and has a first inlet, a first outlet, a second outlet and a third outlet, wherein the first inlet is connected to an external transmission pipeline through an air intake pipeline, the first outlet is connected to the external transmission pipeline through a pressurized mixed transmission pipeline, and the pressurized mixed transmission pipeline is located downstream of the air intake pipeline, and the second outlet is connected to the external transmission pipeline through a gas lift pipeline, and the gas lift pipeline is located upstream of the air intake pipeline;

[0008] A high-pressure dehydration skid having a moisture recovery inlet and a dehydration sewage outlet, wherein the moisture recovery inlet is connected to the third outlet via a CNG moisture recovery pipeline, and the dehydration sewage outlet is connected to the air intake pipeline via a dehydration sewage mixed transport pipeline;

[0009] A gas generator set is electrically connected to the integrated compressor skid and the high-pressure dehydration skid to provide electrical energy to the integrated compressor skid and the high-pressure dehydration skid.

[0010] By adopting the above technical scheme, when the gas lift pressurized mixed transmission and CNG recovery system in the present application is used, the natural gas in the gas well enters the external transmission pipeline, and the natural gas entering the external transmission pipeline enters the integrated compressor skid via the air intake pipeline, so that the integrated compressor skid pressurizes the natural gas and then transmits it to the external transmission pipeline via the pressurized mixed transmission pipeline and is discharged to the downstream pipeline network; because the processing volume of the natural gas by the integrated compressor skid is greater than the original gas discharge volume of the gas well, when the integrated compressor skid is running, the pressure of the natural gas at the wellhead of the gas well will be reduced, the pressure difference between the formation and the wellhead will be increased, and production balance will be achieved, so that the formation pressure can be released to a greater extent, the pressure of the abandoned well will be reduced, the recovery cycle will be extended, and the production capacity of the gas well will be increased, so as to increase the return on investment and realize the function of reducing pressure and increasing production.

[0011] During the pressurization process, when water accumulates in the gas well, the integrated compressor skid injects the pressurized natural gas into the wellbore of the gas well through the gas lift pipeline, and then the accumulated liquid in the wellbore is discharged to the external transmission pipeline, and part of it enters the integrated compressor skid through the air intake pipeline, so that the accumulated liquid is discharged to the downstream of the external transmission pipeline through the pressurized mixed transmission pipeline, and the other part is directly discharged to the downstream through the external transmission pipeline, thereby realizing the gas lift drainage operation. When the gas well with water accumulation is working normally, in order to prevent the wellbore from accumulating liquid again and affecting the production, natural gas can be continuously injected into the wellbore according to the water and gas production of the gas well, so as to maintain the gas-liquid balance and perform continuous gas lift operations to completely solve the problem of liquid accumulation in the wellbore, thereby reducing the formation natural gas flow resistance and achieving the benefits of gas lift drainage and production increase.

[0012] In addition, the natural gas processed by the integrated compressor skid can enter the high-pressure dehydration skid through the CNG wet gas recovery pipeline, so that the high-pressure dehydration skid can deeply dehydrate it to a normal pressure dew point below -62°C, so that the natural gas can directly provide raw materials for the gas generator set to power the integrated compressor skid and the high-pressure dehydration skid, avoiding the need to set up transmission lines on site, reducing the difficulty of gas well exploitation, reducing the basic construction of ground projects, and greatly reducing the total investment cost and construction period.

[0013] In summary, the gas lift, pressurization, mixed transportation and CNG recovery system in this application realizes a full set of processes such as gas lift drainage, pressurization and mixed transportation, and CNG recovery. Each process can be operated independently or flexibly matched according to needs. At the same time, no additional engineering technology changes and equipment modifications are required, which solves the problem of poor adaptability of multiple single functions such as gas lift, pressurization, and CNG recovery.

[0014] The design of traditional wellhead surface engineering transition discreteness has been simplified, effectively reducing the complexity of the process and the difficulty of mining. The modular design of each component has effectively reduced the difficulty of mining and operation and maintenance technology, adapted to a wider range of working conditions, and facilitated well replacement, migration and reconstruction, reducing the permanent infrastructure of surface engineering, and greatly reducing the total investment cost and construction period. The intelligent gas lift and pressure reduction mining technology are combined to reduce the wellhead pressure during the gas lift operation, amplify the production pressure difference, reduce the pressure of abandoned wells, extend the recovery time, and improve the recovery rate.

[0015] Optionally, the high-pressure dehydration skid further has a CNG recovery dry gas outlet, the high-pressure dehydration skid is provided with a CNG recovery dry gas pipeline connected to the CNG recovery dry gas outlet, and a gas storage device is provided at the end of the CNG recovery dry gas pipeline.

[0016] By adopting the above technical solution, when there is no transmission pipeline downstream of the external transmission pipeline, the natural gas deeply dehydrated by the high-pressure dehydration skid can also enter the gas storage device through the CNG recovery dry gas outlet and the CNG recovery dry gas pipeline for storage, avoiding the waste of natural gas venting, which is beneficial to environmental protection. At the same time, it greatly increases the safety of natural gas extraction, enables the natural gas to be fully recycled and utilized, and maximizes the economic benefits and terminal value of the gas well.

[0017] Optionally, the gas storage device includes a CNG filling column disposed at the end of the CNG dry gas recovery pipeline, and the CNG filling column can be connected to a CNG tank truck to transport natural gas to the CNG tank truck.

[0018] By adopting the above technical solution, the natural gas processed by the integrated compressor skid can enter the high-pressure dehydration skid through the CNG wet gas recovery pipeline, so that the high-pressure dehydration skid can deeply dehydrate the natural gas to a normal pressure dew point below -62°C to meet the vehicle natural gas standard, and then re-enter the CNG tank truck after being metered by the CNG filling column to avoid the waste of natural gas venting, which is beneficial to environmental protection. At the same time, it greatly increases the safety of natural gas extraction, enables natural gas to be fully recycled and utilized, maximizes the economic benefits and terminal value of the gas well, and greatly increases the market value of the produced natural gas, so as to meet the natural gas demand at the extraction site in a shorter time.

[0019] Optionally, the gas storage device includes a gas storage tank connected to the CNG dry gas recovery pipeline.

[0020] By adopting the above technical solution, the natural gas processed by the integrated compressor skid can enter the high-pressure dehydration skid through the CNG wet gas recovery pipeline, so that the high-pressure dehydration skid can deeply dehydrate the natural gas to a normal pressure dew point below -62°C. The deeply dehydrated natural gas then enters the gas storage tank through the CNG dry gas recovery pipeline to achieve natural gas recovery, avoid natural gas venting and waste, which is beneficial to environmental protection. At the same time, it greatly increases the safety of natural gas extraction, enables natural gas to be fully recycled, and maximizes the economic benefits and terminal value of the gas well.

[0021] Optionally, the external transmission pipeline is provided with an anti-backflow valve group located between the air intake pipeline and the pressurized mixed transmission pipeline.

[0022] By adopting the above technical solution, since the anti-backflow valve group is arranged between the air intake pipeline and the pressurized mixed transmission pipeline, the natural gas entering the external transmission pipeline through the pressurized mixed transmission pipeline is prevented from flowing back to the upstream of the external transmission pipeline, thereby ensuring the efficiency of natural gas extraction.

[0023] Optionally, the gas lift pipeline is provided with at least one gas lift gas distribution pipeline, each of which is connected to the gas inlet of a gas well, and the external transmission pipeline is provided with at least one output pipeline, each of which is connected to the gas outlet of a gas well, and the number of the gas lift gas distribution pipelines is the same as that of the output pipelines.

[0024] By adopting the above-mentioned technical scheme, the number of gas lift gas distribution pipelines and output pipelines in the present application can be adjusted according to the number of gas wells, so that the gas lift pressurization mixed transportation and CNG recovery system in the present application can act on multiple gas wells at the same time, so as to improve the utilization rate of the gas lift pressurization mixed transportation and CNG recovery system and greatly reduce the natural gas extraction cost, and at the same time greatly reduce the investment cost of natural gas extraction, so as to further improve the return on investment of natural gas extraction.

[0025] Optionally, at least part of the gas lift gas distribution pipeline is provided with a gas lift regulating valve group.

[0026] By adopting the above technical solution, when water accumulates in all or any one of the gas wells, the opening of the gas lift distribution pipeline can be adjusted through the gas lift regulating valve group, and high-pressure natural gas can be injected into the wellbores that require gas lift operations separately or simultaneously, so that the accumulated liquid in the wellbore can be discharged to the external transmission pipeline and into the integrated compressor skid through the air intake pipeline, so as to realize gas lift for all or any one of the gas wells.

[0027] Optionally, the integrated compressor skid includes a reciprocating compressor, a natural gas engine for providing kinetic energy to the reciprocating compressor, a cooler for cooling the reciprocating compressor and the natural gas engine, a separator for separating gas and inter-stage condensed liquid in the reciprocating compressor, and a control system for the natural gas engine.

[0028] By adopting the above technical solution, when the integrated compressor skid is working, the control system sends a start signal to the natural gas engine, which then starts the natural gas engine and provides kinetic energy to the reciprocating compressor, so that the reciprocating compressor pressurizes the natural gas, the separator separates the gas and the interstage liquid of the reciprocating compressor, and the cooler cools the natural gas engine and the reciprocating compressor to reduce the temperature of the reciprocating compressor and the natural gas engine, thereby ensuring the working efficiency of the integrated compressor skid.

[0029] Optionally, the integrated compressor skid further includes a skid seat, and the reciprocating compressor, the natural gas engine, the cooler, the separator and the control system are all arranged on the skid seat.

[0030] By adopting the above technical solution, since the reciprocating compressor, natural gas engine, cooler, separator and control system are all arranged on the skid base, the integration of the integrated compressor skid is realized, so that the integrated compressor skid can be moved, and at the same time, the location where the integrated compressor skid is installed only needs simple compaction treatment, avoiding the need for concrete hardening, reducing the permanent infrastructure construction of the ground project, and greatly reducing the investment cost and construction period.

[0031] Optionally, the integrated compressor skid further includes a sound insulation protective cover, which is disposed outside the reciprocating compressor, the natural gas engine, the cooler, the separator and the control system.

[0032] By adopting the above technical scheme, since the sound insulation protective cover is arranged on the outside of the reciprocating compressor, natural gas engine, cooler, separator and control system, on the one hand, the sound insulation protective cover can soundproof the reciprocating compressor, natural gas engine and cooler to reduce the noise of the integrated compressor skid during operation, thereby greatly improving the working comfort of the staff; on the other hand, the sound insulation protective cover can protect the reciprocating compressor, natural gas engine, cooler and separator to avoid the reciprocating compressor, natural gas engine, cooler and separator from being damaged by objects, thereby reducing the failure rate of the integrated compressor skid to extend the service life of the integrated compressor skid.

[0033] Due to the adoption of the above technical solution, the beneficial effects achieved by this application are as follows:

[0034] The gas lift, pressurization, mixed transportation and CNG recovery system in this application realizes a full set of processes such as gas lift drainage, pressurization and mixed transportation, and CNG recovery. Each process can be operated independently or flexibly matched according to needs. At the same time, no additional engineering technology changes and equipment modifications are required, which solves the problem of poor adaptability of multiple single functions such as gas lift, pressurization, and CNG recovery.

[0035] The design of traditional wellhead surface engineering transition discreteness has been simplified, effectively reducing the complexity of the process and the difficulty of mining. The modular design of each component has effectively reduced the difficulty of mining and operation and maintenance technology, adapted to a wider range of working conditions, and facilitated well replacement, migration and reconstruction, reducing the permanent infrastructure of surface engineering, and greatly reducing the total investment cost and construction period. The intelligent gas lift and pressure reduction mining technology are combined to reduce the wellhead pressure during the gas lift operation, amplify the production pressure difference, reduce the pressure of abandoned wells, extend the recovery time, and improve the recovery rate.

[0036] In addition, the natural gas processed by the integrated compressor skid can enter the high-pressure dehydration skid through the CNG wet gas recovery pipeline, so that the high-pressure dehydration skid can deeply dehydrate it to a normal pressure dew point below -62°C, so that the natural gas can directly provide raw materials for the gas generator set to power the integrated compressor skid and the high-pressure dehydration skid, avoiding the need to set up transmission lines on site, reducing the difficulty of gas well exploitation, reducing the basic construction of ground projects, and greatly reducing the total investment cost and construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0038] Figure 1 This is a schematic structural diagram of a gas lift pressurized mixed transmission and CNG recovery system according to one implementation mode of the present application;

[0039] Figure 2 This is a schematic diagram of the structure of the integrated compressor skid according to one embodiment of the present application, in which the sound insulation protective cover is omitted in the main figure;

[0040] Figure 3 This is a schematic structural diagram of the integrated compressor skid according to one embodiment of the present application, mainly showing a sound insulation protective cover.

[0041] Reference numerals:

[0042] 1. Integrated compressor skid; 2. High-pressure dehydration skid; 3. CNG filling column; 4. Anti-backflow valve group; 5. Gas generator set; 6. Gas lift regulating valve group; 1.1. Pressurized mixed transmission pipeline; 1.2. Gas lift pipeline; 1.3. Intake pipeline; 1.4. CNG wet gas recovery pipeline; 1.5. Dehydration and sewage mixed transmission pipeline; 1.6. CNG dry gas recovery pipeline; 1.7. External transmission pipeline; 1.8. Gas lift gas distribution pipeline; 1.9. Output pipeline; 11. Reciprocating compressor; 12. Natural gas engine; 13. Cooler; 14. Separator; 15. Control system; 16. Sound insulation protection cover; 17. Auxiliary system; 18. Skid seat. DETAILED DESCRIPTION

[0043] In order to more clearly illustrate the overall concept of the present application, a detailed description is given below in an illustrative manner in conjunction with the accompanying drawings.

[0044] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present application is not limited by the specific embodiments disclosed below. It should be noted that the embodiments of the present application and the features in each embodiment may be combined with each other without conflict.

[0045] In addition, in the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "top", "bottom", "inside", "outside", "axial", "radial", "circumferential", etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0046] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0047] In the present application, unless otherwise clearly specified and limited, a first feature "above" or "below" a second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in an appropriate manner in any one or more embodiments or examples.

[0048] Reference Figures 1 to 3 , discloses a gas lift pressurized mixed transmission and CNG recovery system, which includes an integrated compressor skid 1, a high-pressure dehydration skid 2 and a gas generator set 5; wherein the integrated compressor skid 1 is used for pressurizing, gas-liquid separation and gas lift of natural gas and has a first inlet, a first outlet, a second outlet and a third outlet, the first inlet is connected to an external transmission pipeline 1.7 through an intake pipeline 1.3, the first outlet is connected to the external transmission pipeline 1.7 through a pressurized mixed transmission pipeline 1.1, and the pressurized mixed transmission pipeline 1.1 is located downstream of the intake pipeline 1.3, and the third outlet is connected to the external transmission pipeline 1.7 through a pressure-boosted mixed transmission pipeline 1.1. The second outlet is connected to the external transmission pipeline 1.7 through the gas lift pipeline 1.2, and the gas lift pipeline 1.2 is located upstream of the air intake pipeline 1.3; the high-pressure dehydration skid 2 has a moisture recovery inlet and a dehydration sewage outlet, the moisture recovery inlet is connected to the third outlet through the CNG moisture recovery pipeline 1.4, and the dehydration sewage outlet is connected to the air intake pipeline 1.3 through the dehydration sewage mixed transmission pipeline 1.5; the gas generator set 5 is electrically connected to the integrated compressor skid 1 and the high-pressure dehydration skid 2 to provide electrical energy to the integrated compressor skid 1 and the high-pressure dehydration skid 2.

[0049] It can be understood that the external transmission system is connected to the gas well, that is, the natural gas in the external transmission system comes from the gas well.

[0050] It should be noted that the above-mentioned pressurized mixed pipeline 1.1 being located downstream of the air intake pipeline 1.3 means that the connecting position of the pressurized mixed pipeline 1.1 and the external transmission pipeline 1.7 is located downstream of the connecting position of the air intake pipeline 1.3 and the external transmission pipeline 1.7; the gas lift pipeline 1.2 being located upstream of the air intake pipeline 1.3 means that the connecting position of the gas lift pipeline 1.2 and the external transmission pipeline 1.7 is located upstream of the connecting position of the air intake pipeline 1.3 and the external transmission pipeline 1.7, that is, the gas lift pipeline 1.2, the air intake pipeline 1.3 and the pressurized mixed pipeline 1.1 are connected in sequence along the extending direction of the external transmission pipeline 1.7.

[0051] When the gas lift pressurized mixed transmission and CNG recovery system in the present application is used, the natural gas in the gas well enters the external transmission pipeline 1.7, and the natural gas entering the external transmission pipeline 1.7 enters the integrated compressor skid 1 via the air intake pipeline 1.3, so that the integrated compressor skid 1 pressurizes the natural gas and then transmits it to the external transmission pipeline 1.7 via the pressurized mixed transmission pipeline 1.1 and is discharged to the downstream pipeline network; because the processing capacity of the natural gas by the integrated compressor skid 1 is greater than the original gas discharge of the gas well, when the integrated compressor skid 1 is running, the pressure of the natural gas at the wellhead of the gas well will be reduced, the pressure difference between the formation and the wellhead will be increased, and production balance will be achieved, so that the formation pressure can be released to a greater extent, the pressure of the abandoned well will be reduced, the recovery period will be extended, and the production capacity of the gas well will be increased, so as to increase the return on investment and realize the function of reducing pressure and increasing production.

[0052] During the pressurization process, when water accumulates in the gas well, the integrated compressor skid 1 injects the pressurized natural gas into the wellbore of the gas well through the gas lift pipeline 1.2, and then the accumulated liquid in the wellbore is discharged to the external transmission pipeline 1.7 and a part of it enters the integrated compressor skid 1 through the air intake pipeline 1.3, so that the accumulated liquid is discharged into the downstream of the external transmission pipeline 1.7 through the pressurized mixed transmission pipeline 1.1, and the other part is directly discharged into the downstream through the external transmission pipeline 1.7, thereby realizing the gas lift drainage operation. When the gas well with water accumulation works normally, in order to prevent the wellbore from accumulating liquid again and affecting the production, natural gas can be continuously injected into the wellbore according to the water and gas production of the gas well, so as to maintain the gas-liquid balance and perform continuous gas lift operations to completely solve the problem of liquid accumulation in the wellbore, thereby reducing the formation natural gas flow resistance and realizing the benefits of gas lift drainage and production increase.

[0053] In addition, the natural gas processed by the integrated compressor skid 1 can enter the high-pressure dehydration skid 2 via the CNG wet gas recovery pipeline 1.4, so that the high-pressure dehydration skid 2 can deeply dehydrate it to a normal pressure dew point below -62°C, so that the natural gas can directly provide raw materials for the gas generator set 5 to power the integrated compressor skid 1 and the high-pressure dehydration skid 2, avoiding the need to set up transmission lines on site, reducing the difficulty of gas well exploitation, reducing the basic construction of ground projects, and greatly reducing the total investment cost and construction period.

[0054] In summary, the gas lift, pressurization, mixed transportation and CNG recovery system in this application realizes a full set of processes such as gas lift drainage, pressurization and mixed transportation, and CNG recovery. Each process can be operated independently or flexibly matched according to needs. At the same time, no additional engineering technology changes and equipment modifications are required, which solves the problem of poor adaptability of multiple single functions such as gas lift, pressurization, and CNG recovery.

[0055] The design of traditional wellhead surface engineering transition discreteness has been simplified, effectively reducing the complexity of the process and the difficulty of mining. The modular design of each component has effectively reduced the difficulty of mining and operation and maintenance technology, adapted to a wider range of working conditions, and facilitated well replacement, migration and reconstruction, reducing the permanent infrastructure of surface engineering, and greatly reducing the total investment cost and construction period. The intelligent gas lift and pressure reduction mining technology are combined to reduce the wellhead pressure during the gas lift operation, amplify the production pressure difference, reduce the pressure of abandoned wells, extend the recovery time, and improve the recovery rate.

[0056] Preferably, the dehydration and sewage mixed transportation pipeline 1.5 is provided with a check valve to prevent the natural gas in the air intake pipeline 1.3 from entering the high-pressure dehydration skid 2 via the dehydration and sewage mixed transportation pipeline 1.5, so as to ensure the pressurization effect of the natural gas.

[0057] In a preferred embodiment, referring to Figure 1 The high-pressure dehydration skid 2 also has a CNG recovery dry gas outlet. The high-pressure dehydration skid 2 is provided with a CNG recovery dry gas pipeline 1.6 connected to the CNG recovery dry gas outlet. A gas storage device is provided at the end of the CNG recovery dry gas pipeline 1.6.

[0058] Specifically, when there is no transmission pipeline downstream of the external transmission pipeline 1.7, the natural gas deeply dehydrated by the high-pressure dehydration skid 2 can also enter the gas storage device through the CNG recovery dry gas outlet and the CNG recovery dry gas pipeline 1.6 for storage, avoiding the waste of natural gas venting, which is beneficial to environmental protection, and at the same time greatly increases the safety of natural gas extraction, so that the natural gas can be fully recycled and utilized, and the economic benefits and terminal value of the gas well can be maximized.

[0059] The present application does not specifically limit the structure of the gas storage device, and the gas storage device may adopt any one of the following embodiments:

[0060] Embodiment 1, in this embodiment, refer to Figure 1 The gas storage device includes a CNG gas filling column 3 arranged at the end of the CNG recovery dry gas pipeline 1.6, and the CNG gas filling column 3 can be connected to the CNG tank truck to transport the natural gas to the CNG tank truck.

[0061] Specifically, the natural gas processed by the integrated compressor skid 1 can enter the high-pressure dehydration skid 2 through the CNG wet gas recovery pipeline 1.4, so that the high-pressure dehydration skid 2 can deeply dehydrate the natural gas to a normal pressure dew point below -62°C to meet the vehicle natural gas standard, and then re-enter the CNG tank truck after being measured by the CNG filling column 3 to avoid the waste of natural gas venting, which is beneficial to environmental protection. At the same time, it greatly increases the safety of natural gas extraction, allows natural gas to be fully recycled, maximizes the economic benefits and terminal value of the gas well, and greatly increases the market value of the extracted natural gas to meet the natural gas demand of the extraction site in a shorter time. At the same time, the CNG filling column 3 can measure the volume of natural gas transported to the CNG tank truck so as to calculate and count the returns generated by natural gas extraction.

[0062] Embodiment 2: In this embodiment, the gas storage device includes a gas storage tank connected to the CNG recovery dry gas pipeline 1.6.

[0063] Specifically, the natural gas processed by the integrated compressor skid 1 can enter the high-pressure dehydration skid 2 via the CNG wet gas recovery pipeline 1.4, so that the high-pressure dehydration skid 2 deeply dehydrates the natural gas to a normal pressure dew point below -62°C. The deeply dehydrated natural gas then enters the gas storage tank via the CNG dry gas recovery pipeline 1.6 to achieve natural gas recovery, thereby avoiding the waste of natural gas venting, which is beneficial to environmental protection, and at the same time greatly increases the safety of natural gas extraction, so that the natural gas can be fully recycled and utilized, and the economic benefits and terminal value of the gas well can be maximized.

[0064] In a preferred embodiment, referring to Figure 1 The external transmission pipeline 1.7 is provided with an anti-backflow valve group 4 located between the air intake pipeline 1.3 and the pressurized mixed transmission pipeline 1.1, thereby preventing the natural gas entering the external transmission pipeline 1.7 through the pressurized mixed transmission pipeline 1.1 from flowing back to the upstream of the external transmission pipeline 1.7, so as to ensure the efficiency of natural gas extraction.

[0065] In a preferred embodiment, referring to Figure 1The gas lift pipeline 1.2 is provided with at least one gas lift gas distribution pipeline 1.8, each gas lift gas distribution pipeline 1.8 is connected to a gas well, and the external transmission pipeline 1.7 is provided with at least one output pipeline 1.9, each output pipeline 1.9 is connected to a gas well, and the number of gas lift gas distribution pipelines 1.8 and output pipelines 1.9 is the same, so that the number of gas lift gas distribution pipelines 1.8 and output pipelines 1.9 in the present application can be adjusted according to the number of gas wells, that is, when there are multiple gas wells at the mining site, the gas lift gas distribution pipeline 1.8 can be increased. The number of distribution pipelines 1.8 and output pipelines 1.9 is such that each gas well can be connected to the gas lift gas pipeline 1.2 and the external transmission pipeline 1.7 respectively through the corresponding gas lift gas distribution pipeline 1.8 and the output pipeline 1.9, so that the gas lift pressurization mixed transportation and CNG recovery system in the present application can act on multiple gas wells at the same time, so as to improve the utilization rate of the gas lift pressurization mixed transportation and CNG recovery system and greatly reduce the cost of natural gas extraction, and at the same time greatly reduce the investment cost of natural gas extraction, so as to further improve the return on investment of natural gas extraction.

[0066] Further, see Figure 1 At least part of the gas lift gas distribution pipeline 1.8 is provided with a gas lift regulating valve group 6.

[0067] Specifically, when water accumulates in all or any one of the gas wells, the opening of the gas lift gas distribution pipeline 1.8 is adjusted through the gas lift regulating valve group 6, and high-pressure natural gas can be injected into the wellbores that require gas lift operations separately or simultaneously, so that the accumulated liquid in the wellbores is discharged to the external transmission pipeline 1.7 and a part of it enters the integrated compressor skid 1 through the air intake pipeline 1.3, so that the accumulated liquid is input to the downstream of the external transmission pipeline 1.7 through the booster mixed transmission pipeline 1.1, and the other part is directly discharged to the downstream through the external transmission pipeline 1.7, so as to realize gas lift for all or any one of the gas wells.

[0068] Preferably, all gas lift gas distribution pipelines 1.8 are provided with a gas lift regulating valve assembly 6.

[0069] The present application does not specifically limit the number of gas lift gas distribution pipelines 1.8. In a specific natural gas production scenario, four gas lift gas distribution pipelines 1.8 are provided, that is, four gas wells share one gas lift pressurization mixed transmission and CNG recovery system; the vertical depth of a single well is about 2500m to 3500m, the horizontal well depth is 2000m to 3500m, the manifold design transmission pressure is 4.0MPag, the average platform production time is 4 years, and the current daily total gas production has decayed to 1 to 3.5×10 4 Nm 3 / d, the oil pipeline transmission pressure decayed to below 1.5MPag, and gravity transmission was no longer possible. Before using the gas lift pressurized mixed transmission and CNG recovery system in this application, the platform implemented an intermittent production mode, that is, production for a period of time, shutting down the well to hold the pressure, and then transmitting to the outside, a reciprocating cycle, unable to produce normally and continuously, with low gas production and low efficiency; some of the gas wells have experienced serious water accumulation and are facing the risk of complete flooding and shutdown.

[0070] After using the gas lift pressurized mixed transmission and CNG recovery system in the present application, on the one hand, it is necessary to solve the problem of water accumulation in the gas well; on the other hand, the pressure at the wellhead is reduced, and a mechanical supercharging method is used to pressurize the low-pressure natural gas at the wellhead and transmit it to the pipeline network, thereby reducing the wellhead natural gas pressure, increasing the production pressure difference, reducing the abandonment pressure of the gas well, and extending the recovery period. Considering that there is no dedicated sewage treatment equipment at the well site, the sewage treatment cost is reduced, and a dehydration sewage mixed transmission pipeline 1.5 is used to transmit the liquid discharged from the gas well to the downstream gathering and processing station via an external transmission pipeline.

[0071] In a preferred embodiment, referring to Figure 2 The integrated compressor skid 1 includes a reciprocating compressor 11, a natural gas engine 12 for providing kinetic energy to the reciprocating compressor 11, a cooler 13 for cooling the reciprocating compressor 11 and the natural gas engine 12, a separator 14 for separating gas and inter-stage condensed liquid from the reciprocating compressor 11, and a control system 15 for the natural gas engine 12.

[0072] Specifically, when the integrated compressor skid 1 is working, the control system 15 sends a start signal to the natural gas engine 12, thereby starting the natural gas engine 12 and providing kinetic energy to the reciprocating compressor 11, so that the reciprocating compressor 11 pressurizes the natural gas, the separator 14 separates the gas and the interstage liquid of the reciprocating compressor 11, and the cooler 13 cools the natural gas engine 12 and the reciprocating compressor 11 to reduce the temperature of the reciprocating compressor 11 and the natural gas engine 12, thereby ensuring the working efficiency of the integrated compressor skid 1.

[0073] Preferably, the reciprocating compressor 11 adopts two rows of 4-stage compression, with a design power of 216kw and a maximum speed of 1800rpm. The first and second stage cylinders are on the right side of the crankshaft, and the third and fourth stage cylinders are on the left side. They all adopt differential single-acting air-cooled cylinders, with compact structure, small size, high power, stable performance and high reliability. The natural gas engine 12 is connected to the reciprocating compressor 11 by transmission, for example, the two are directly driven, and the power of the natural gas engine 12 is 210kw and the maximum speed is 1800rpm.

[0074] Further, see Figure 2The integrated compressor skid 1 also includes a skid seat 18. The reciprocating compressor 11, the natural gas engine 12, the cooler 13, the separator 14 and the control system 15 are all arranged on the skid seat 18, thereby realizing the integration of the integrated compressor skid 1, so that the integrated compressor skid 1 can be moved. At the same time, the location where the integrated compressor skid 1 is installed only needs to be simply compacted, avoiding the need for concrete hardening, reducing the permanent infrastructure construction of the ground project, and greatly reducing the investment cost and construction period.

[0075] Preferably, the cooler 13 is an air-cooled cooler 13, and the fan of the cooler 13 is connected to the output shaft of the natural gas engine 12 through a belt and a pulley transmission; the skid seat 18 has a first end and a second end opposite to the first end, the cooler 13 is arranged at the first end, and the airflow generated by the cooler 13 is directed toward the second end to facilitate the air intake of the cooler 13, so as to improve the cooling effect on the natural gas engine 12 and the reciprocating compressor 11, and at the same time, it can also ventilate the integrated compressor skid 1 to avoid the occurrence of combustible gas gathering in the integrated compressor skid 1 when natural gas leaks, so as to greatly improve the safety of the gas lift, pressurization and mixed transportation and CNG recovery system.

[0076] The separator 14 is arranged at the air inlet of each stage of the reciprocating compressor 11, and is used to separate the intake air and the liquid condensed between the stages to ensure the safe operation of the compressor; and a mixed transport storage tank is arranged at the lower part of the separator 14, which can store the discharge liquid of each stage, and when the discharge liquid is stored to the set liquid level, it is discharged to the downstream of the external transmission pipeline 1.7 by high-pressure gas, so as to realize the gas-liquid mixed transport function.

[0077] The control system 15 is arranged at the side of the second end for operation and maintenance. The control system 15 includes a PLC controller and a starter cabinet, which can not only control the start and stop of the natural gas engine 12 and the separator 14, but also monitor the working status in real time.

[0078] Further, see Figure 3 The integrated compressor skid 1 further comprises a soundproof protective cover 16, which is arranged outside the reciprocating compressor 11, the natural gas engine 12, the cooler 13, the separator 14 and the control system 15. On the one hand, the soundproof protective cover 16 can soundproof the reciprocating compressor 11, the natural gas engine 12 and the cooler 13 to reduce the noise during the operation of the integrated compressor skid 1, thereby greatly improving the working comfort of the staff. On the other hand, the soundproof protective cover 16 can protect the reciprocating compressor, the natural gas engine 12, the cooler 13 and the separator 14 to avoid the reciprocating compressor, the natural gas engine 12, the cooler 13 and the separator 14 from being damaged by objects, thereby reducing the failure rate of the integrated compressor skid 1 to extend the service life of the integrated compressor skid 1.

[0079] Preferably, the soundproof protective cover 16 is arranged on the top of the skid seat 18, so that the soundproof protective cover 16 and the skid seat 18 together form a storage space, and other structures of the integrated compressor skid 1 except the skid seat 18 and the soundproof protective cover 16 are all arranged in the storage space. The soundproof protective cover 16 is made of steel material and a material with fireproof and soundproof properties, and the soundproof protective cover 16 is provided with an air inlet at the first end corresponding to the skid seat 18 and an air outlet at the second end corresponding to the skid seat 18, so that the airflow in the storage space can flow and exchange with the outside.

[0080] Furthermore, the side of the sound insulation protection cover 16 is provided with an openable door body to facilitate the maintenance of the integrated compressor skid 1, and the four corners of the top of the sound insulation protection cover 16 are provided with lifting holes to facilitate the lifting of the integrated compressor skid 1.

[0081] Further, see Figure 2 The integrated compressor skid 1 also includes an auxiliary system 17, which includes a process gas system, a venting system, a sewage system, a mixed transport system, a compressor lubrication system, an engine auxiliary system, and a piping system connecting various systems and structures of the integrated compressor skid 1, wherein the engine auxiliary system includes an engine lubrication system, a cooling system, and a fuel supply system.

[0082] Anything not described in this application can be achieved by adopting or drawing on existing technologies.

[0083] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0084] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A gas lift pressurized mixed transmission and CNG recovery system, characterized in that: include: An integrated compressor skid (1) is used for pressurizing, gas-liquid separation and gas lifting of natural gas and has a first inlet, a first outlet, a second outlet and a third outlet, wherein the first inlet is connected to an external transmission pipeline (1.7) via an air intake pipeline (1.3), the first outlet is connected to an external transmission pipeline (1.7) via a pressurized mixed transmission pipeline (1.1), and the pressurized mixed transmission pipeline (1.1) is located downstream of the air intake pipeline (1.3), and the second outlet is connected to an external transmission pipeline (1.7) via a gas lift pipeline (1.2), and the gas lift pipeline (1.2) is located upstream of the air intake pipeline (1.3); A high-pressure dehydration skid (2) having a moisture recovery inlet and a dehydration sewage outlet, wherein the moisture recovery inlet is connected to the third outlet via a CNG moisture recovery pipeline (1.4), and the dehydration sewage outlet is connected to the air intake pipeline (1.3) via a dehydration sewage mixed transport pipeline (1.5); A gas-fired generator set (5) is electrically connected to the integrated compressor skid (1) and the high-pressure dehydration skid (2) to provide electrical energy to the integrated compressor skid (1) and the high-pressure dehydration skid (2).

2. The apparatus pressurization mixed transmission and CNG recovery system according to claim 1 is characterized in that: The high-pressure dehydration skid (2) also has a CNG recovery dry gas outlet, and the high-pressure dehydration skid (2) is provided with a CNG recovery dry gas pipeline (1.6) connected to the CNG recovery dry gas outlet, and a gas storage device is provided at the end of the CNG recovery dry gas pipeline (1.6).

3. The apparatus pressurization mixed transmission and CNG recovery system according to claim 2 is characterized in that: The gas storage device comprises a CNG gas filling column (3) arranged at the end of the CNG recovery dry gas pipeline (1.6), and the CNG gas filling column (3) can be connected to a CNG tank truck to transport natural gas to the CNG tank truck.

4. The apparatus pressurization mixed transmission and CNG recovery system according to claim 2 is characterized in that: The gas storage device comprises a gas storage tank connected to the CNG recovery dry gas pipeline (1.6).

5. The apparatus pressurization mixed transmission and CNG recovery system according to claim 1 is characterized in that: The external transmission pipeline (1.7) is provided with an anti-backflow valve group (4) located between the air intake pipeline (1.3) and the pressurized mixed transmission pipeline (1.1).

6. The apparatus pressurization mixed transmission and CNG recovery system according to claim 1, characterized in that: The gas lift pipeline (1.2) is provided with at least one gas lift gas distribution pipeline (1.8), each of which is connected to the gas inlet of a gas well; the external transmission pipeline (1.7) is provided with at least one output pipeline (1.9), each of which is connected to the gas outlet of a gas well, and the number of the gas lift gas distribution pipelines (1.8) is the same as that of the output pipelines (1.9).

7. The apparatus pressurization mixed transmission and CNG recovery system according to claim 6, characterized in that: At least part of the gas lift gas distribution pipeline (1.8) is provided with a gas lift regulating valve group (6).

8. The apparatus pressurization mixed transmission and CNG recovery system according to claim 1, characterized in that: The integrated compressor skid (1) comprises a reciprocating compressor (11), a natural gas engine (12) for providing kinetic energy to the reciprocating compressor (11), a cooler (13) for cooling the reciprocating compressor (11) and the natural gas engine (12), a separator (14) for separating gas and inter-stage condensed liquid in the reciprocating compressor (11), and a control system (15) for controlling the natural gas engine (12).

9. The apparatus pressurization mixed transmission and CNG recovery system according to claim 8, characterized in that: The integrated compressor skid (1) further comprises a skid seat (18), and the reciprocating compressor (11), the natural gas engine (12), the cooler (13), the separator (14) and the control system (15) are all arranged on the skid seat (18).

10. The apparatus pressurization mixed transmission and CNG recovery system according to claim 8, characterized in that: The integrated compressor skid (1) further comprises a soundproof protective cover (16), wherein the soundproof protective cover (16) is arranged outside the reciprocating compressor (11), the natural gas engine (12), the cooler (13), the separator (14) and the control system (15).

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