CN110714919A

CN110714919A - Oilfield associated gas recovery method and device

Info

Publication number: CN110714919A
Application number: CN201911150120.9A
Authority: CN
Inventors: 李牧坤; 林忠灿; 齐园园; 林本常
Original assignee: Xi'an Delin Petroleum Engineering Co Ltd
Current assignee: Shaanxi Aerospace Delin Science And Technology Group Co ltd; Xi'an Delin Petroleum Engineering Co ltd
Priority date: 2019-11-21
Filing date: 2019-11-21
Publication date: 2020-01-21
Anticipated expiration: 2039-11-21
Also published as: CN110714919B

Abstract

The application provides an oil field associated gas recovery method and device, the device includes the triangle rotor compressor, air inlet, inlet and discharge port have been seted up on the cylinder body of triangle rotor compressor, the triangle rotor forward rotation and reverse locking that set up in the cylinder body, air inlet and oil well sheathed tube low pressure gas export intercommunication, oil well oil pipe's high pressure oil export with be responsible for the intercommunication, be responsible for on first, two branch pipes respectively with inlet and discharge port intercommunication, the direction of switching on of being responsible for between first, two branch pipes switches on for being exported to the defeated pipeline by high pressure oil and switch on outward. The pressure difference formed by the high pressure at the liquid inlet and the low pressure at the liquid outlet is utilized to realize that the triangular rotor operates to suck and recover the low-pressure associated gas in the oil well casing pipe, the compression and recovery of the low-pressure associated gas in the oil well casing pipe can be completed without additionally providing power for sucking and recovering the low-pressure associated gas, and the recovery cost of the associated gas in the oil well casing pipe is greatly reduced.

Description

Oilfield associated gas recovery method and device

Technical Field

The application relates to the technical field of petroleum and natural gas development, in particular to a method and a device for recovering associated gas in an oil field.

Background

Along with the environment-friendly situation that the resource of the petroleum associated gas and the oil-gas exploitation are more and more strict, the low pressure and a small amount of wellhead associated gas which are not paid attention to before are not allowed to be discharged and burnt in an extensive manner any more, so that the development of the oil-gas mixed transportation technology in China is promoted, the natural gas can be enriched in an oil well casing pipe in the oil well production process, and if the natural gas in the oil well casing pipe cannot be released in time, the air pressure in the oil well casing pipe can be increased, the working fluid level of an oil well is reduced, and the normal production of the oil well is influenced.

Therefore, an oil-gas mixed transportation pump is required to be used as a key device to discharge associated gas in an oil well casing to reduce the gas pressure in the oil well casing, the associated gas generally refers to natural gas which is symbiotic with oil, wherein the oil-gas mixed transportation pump requires the performance of both a pump and a compressor, however, devices such as a screw pump, a synchronous rotary gas-liquid mixed transportation pump and a swing rotor gas-liquid mixed transportation pump in the prior art cannot be compatible, and in addition, the rotary gas-liquid mixed transportation pump and the swing rotor gas-liquid mixed transportation pump need a motor to provide the operation power of the mixed transportation pump, so that the recovery cost of the associated gas in the oil well casing is increased.

Disclosure of Invention

The application aims to provide a method and a device capable of recovering low-pressure associated gas in an oil well casing and reducing recovery cost.

In order to achieve the purpose, the application provides an oil field associated gas recovery method, which is used for an oil field associated gas recovery device, wherein the oil field associated gas recovery device comprises a triangular rotor compressor, a cylinder body of the triangular rotor compressor is provided with an air inlet, a liquid inlet and a discharge port, a triangular rotor arranged in the cylinder body rotates forwards and locks reversely, the triangular rotor and the cylinder body are matched to form independent first, second and third chambers, the air inlet is communicated with a low-pressure gas outlet of an oil well casing, a high-pressure oil outlet of the oil well oil pipe is communicated with a main pipe, first and second branch pipes on the main pipe are respectively communicated with the liquid inlet and the discharge port, and the conducting direction of the main pipe between the first and second branch pipes is conducted from the high-pressure oil outlet to an external transmission pipeline;

when the pumping unit connected with the oil well pipe is in the down stroke, the method comprises the following steps of S1: the low-pressure associated gas in the oil well casing pipe enters the first cavity through the air inlet of the triangular rotor compressor, high-pressure oil of the output pipeline flows back to the liquid inlet of the triangular rotor compressor to enter the second cavity, and the triangular rotor of the triangular rotor compressor is driven to rotate by the pressure difference formed by the high pressure at the liquid inlet of the triangular rotor compressor and the low pressure at the discharge outlet;

step S2: the triangular rotor of the triangular rotor compressor rotates to enable the first cavity to be communicated with the liquid inlet, and high-pressure oil enters the first cavity and is mixed with low-pressure associated gas to form a mixed medium;

step S3: the triangular rotor of the triangular rotor compressor rotates to compress the mixed medium in the first chamber;

step S4: the triangular rotor of the triangular rotor compressor rotates to enable the first chamber to be communicated with a discharge port, and the mixed medium is conveyed into an oil well oil pipe through the discharge port;

the pumping unit is in the upstroke, two liang isolations of air inlet, inlet and discharge port are gone up to the triangle rotor of triangle rotor compressor, and the oil pressure of inlet department equals with the pressure of discharge port, and triangle rotor compressor stall, the fluid of pumping unit extraction and the mixed medium that stores up in the oil well oil pipe are carried from the outside pipeline of high-pressure oil export, accomplish the compression of low pressure associated gas is retrieved in the oil well sleeve pipe.

Optionally, a check valve is arranged on the main pipe body between the first branch pipe and the second branch pipe, and the communication direction of the check valve is from the high-pressure oil outlet to the external transmission pipeline;

the step S1 further includes: the check valve limits the high-pressure oil of the output pipeline to flow back to the oil pipe of the oil well;

the oil produced by the oil pumping unit and the mixed medium stored in the oil pipe of the oil well are conveyed to an external pipeline through a one-way valve from a high-pressure oil outlet.

The application also provides an oilfield associated gas recovery device, which comprises a triangular rotor compressor, wherein an air inlet, an inlet and a discharge port are formed in a cylinder body of the triangular rotor compressor, a triangular rotor arranged in the cylinder body rotates forwards and locks reversely, the air inlet is communicated with a low-pressure gas outlet of an oil well casing, a high-pressure oil outlet of an oil well oil pipe is communicated with a main pipe, a first branch pipe and a second branch pipe on the main pipe are respectively communicated with the inlet and the discharge port, and the conducting direction of the main pipe between the first branch pipe and the second branch pipe is conducted from the high-pressure oil outlet to an external transmission pipeline;

the pumping unit connected with the oil well oil pipe is in a lower stroke, the triangular rotor compressor performs suction compression on low-pressure associated gas in the oil well casing pipe and mixes the low-pressure associated gas with high-pressure oil at a high-pressure oil outlet to form mixed medium, and the mixed medium is conveyed into the oil well oil pipe from the discharge port;

and when the oil pumping unit is in an upper stroke, the oil extracted from the oil pipe of the oil well and the mixed medium accumulated in the oil pipe of the oil well are conveyed to an external transmission pipeline from a high-pressure oil outlet, so that the compression and recovery of the low-pressure associated gas in the oil well casing pipe are completed.

Optionally, a check valve is arranged on the main pipe body between the first branch pipe and the second branch pipe, and the communication direction of the check valve is from the high-pressure oil outlet to the external transmission pipeline.

Optionally, the main pipe is provided with a gate valve connected in parallel with the check valve.

Optionally, a first ball valve and a second ball valve are respectively arranged on the pipeline where the check valve and the gate valve are connected in parallel.

Optionally, a third ball valve is arranged on a pipeline of the air inlet communicated with the low-pressure air outlet of the oil well casing, and a fourth ball valve is arranged on the second branch pipe.

Optionally, the air inlet and the exhaust port are arranged adjacent to each other and on one side of the cylinder body, and the liquid inlet is on the other side of the cylinder body.

Optionally, an inner gear ring is arranged in the middle of the triangular rotor, a transmission shaft is arranged in the cylinder body, one end of the transmission shaft is located in a cavity of the cylinder body, a gear is arranged at the end of the transmission shaft, the other end of the transmission shaft is connected with a power unit, and the gear at one end of the transmission shaft is in meshing transmission with the inner gear ring of the triangular rotor.

Optionally, a pipe orifice at one end of the main pipe is connected with a high-pressure oil outlet of an oil well oil pipe, and a pipe orifice at the other end of the main pipe is communicated with an external pipeline.

Compared with the prior art, the technical effect of this application does: utilize the pressure differential of inlet opening department and exhalant outlet department, realize the unpowered operation of the triangle rotor of triangle rotor compressor to carry out suction recovery to the low pressure associated gas in the oil well sleeve pipe, need not additionally to provide the power of carrying out suction recovery to the low pressure gas, just can accomplish the compression recovery of associated gas in the oil well sleeve pipe, reduce the recovery cost of associated gas in the oil well sleeve pipe by a wide margin.

Drawings

FIG. 1 is a schematic view of the pumping unit of the present application in a down stroke operating condition;

FIG. 2 is a schematic view of the pumping unit in an up stroke state according to the present application;

fig. 3a to 3e are schematic views illustrating the operation of the delta rotor compressor.

In the reference numerals, 1-oil pumping unit, 10-triangle rotor compressor, 11-cylinder body, 12-triangle rotor, 111-air inlet, 112-liquid inlet and 113-discharge outlet; 20-oil well casing, 21-low pressure gas outlet; 30-oil well oil pipe, 31-high pressure oil outlet; 40-one-way valve, 41-first ball valve, 42-second ball valve, 43-third ball valve, 44-fourth ball valve, 45-gate valve; 51-a first branch, 52-a second branch; 60-external pipeline.

Detailed Description

The following description of specific embodiments of the present application refers to the accompanying drawings.

In this document, "upper", "lower", "front", "rear", "left", "right", and the like are used only to indicate relative positional relationships between relevant portions, and do not limit absolute positions of the relevant portions.

In this document, "first", "second", and the like are used only for distinguishing one from another, and do not indicate the degree and order of importance, the premise that each other exists, and the like.

In this context, "equal", "same", etc. are not strictly mathematical and/or geometric limitations, but also include tolerances as would be understood by a person skilled in the art and allowed for manufacturing or use, etc.

Unless otherwise indicated, numerical ranges herein include not only the entire range within its two endpoints, but also several sub-ranges subsumed therein.

The application provides an oilfield associated gas recovery device, including triangle rotor compressor 10, air inlet 111, inlet 112 and discharge port 113 have been seted up on the cylinder body 11 of triangle rotor compressor 10, the triangle rotor 12 forward rotation and the reverse locking that set up in the cylinder body 11, triangle rotor 12 forms independent first, two, three cavities with the cooperation of cylinder body 11, air inlet 111 and oil well sleeve pipe 20's low pressure gas export 21 intercommunication, oil well oil pipe 30's high pressure oil export 31 with be responsible for the intercommunication, be responsible for first, two

branch pipes

51, 52 respectively with inlet 12 and discharge port 113 intercommunication, the direction of switching on of being responsible for between first, two

branch pipes

51, 52 is for being switched on to outer pipeline 60 by high pressure oil export 31;

the pumping unit 1 connected with the oil well oil pipe 30 is in a down stroke, the triangular rotor compressor 10 performs suction compression on low-pressure associated gas in the oil well casing 20 and mixes the low-pressure associated gas with high-pressure oil at the high-pressure oil outlet 31 to form a mixed medium, and the mixed medium is conveyed into the oil well oil pipe 30 through the discharge port 113;

when the pumping unit 1 is in the upper stroke, the oil extracted from the oil well pipe 30 and the mixed medium accumulated in the oil well pipe 30 are conveyed from the high-pressure oil outlet 31 to the external conveying pipeline 60, so that the compression and recovery of the low-pressure associated gas in the oil well casing 20 are completed.

Referring to fig. 1 and 2, the hollow arrows in the drawing indicate low pressure associated gas to be recovered in the well casing 20, the solid arrows indicate high pressure oil that is returned, and the double-tailed hollow arrows indicate the mixing medium.

In the present application, the conducting direction of the main pipe between the first branch pipe 51 and the second branch pipe 52 is from the high-pressure oil outlet 41 to the external pipeline 60, that is, the medium in the main pipe can be transported from the high-pressure oil outlet 41 to the external pipeline 60, and the medium in the main pipe is cut off from the direction of the external high-pressure oil outlet 31.

When the pumping unit 1 is in a lower stroke in the working state, the air pressure at the air inlet 111 is P1, the flowing direction of the medium in the main pipe from the outside to the high-pressure oil outlet 41 is cut off, the backflow high-pressure oil of the main pipe directly flows to the liquid inlet 112, the pressure at the liquid inlet 112 maintains P2, at this time, the pressure P2 at the liquid inlet 112 is far greater than the pressure P3 of the discharge port 113, due to the pressure difference formed between the liquid inlet 112 and the discharge port 113, and the triangular rotor 12 arranged in the cylinder body 11 rotates forward and locks reversely, so that the high pressure at the liquid inlet 112 drives the triangular rotor 12 to rotate along the direction of the increase of the volume of the cylinder chamber, so as to realize the forward rotation of the triangular rotor 12, and the low-pressure associated gas in the casing 20 is pumped into the chamber formed by the triangular rotor 12 and the cylinder body.

The operation of the delta rotor compressor will be described in detail with reference to fig. 3a to 3 e.

The low pressure associated gas in the well casing 20 in fig. 3a enters the first chamber a through the gas inlet 111, the high pressure oil in the well tubing 30 enters the second chamber b through the liquid inlet 112, the discharge port 113 is communicated with the third chamber c, and the high pressure in the second chamber b and the low pressure in the third chamber c form a pressure difference.

The high pressure in the second chamber b in fig. 3b will drive the delta rotor 12 to rotate in the direction of the volume increase of the second chamber b, the delta rotor 12 will rotate in the forward direction to suck the low pressure associated gas due to the forward rotation and reverse locking of the delta rotor 12, and the delta rotor 12 rotates so that the first chamber a forms a closed chamber.

In fig. 3c, the high-pressure oil in the outgoing line 60 flows back to the first chamber a and is mixed with the low-pressure associated gas to form a mixed medium.

In fig. 3d the triangular rotor 12 is rotating in the forward direction, the volume of the first chamber a is reduced and the mixed medium in the first chamber a is compressed.

The mixed medium in the first chamber a in fig. 3e is pressurized and discharged to the well tubing 30, and the process is one working cycle of the delta rotor compressor 10.

The oil-gas mixed medium is conveyed into the oil well oil pipe 30 through the discharge port 113, the oil-gas mixed medium is accumulated in the oil well oil pipe 30, the pumping unit 1 is in an up-stroke, the triangular rotor 12 of the triangular rotor compressor 10 isolates the air inlet 111, the liquid inlet 112 and the discharge port 113 in pairs, the oil pressure at the liquid inlet 112 is almost equal to the pressure at the discharge port 113, that is, the triangular rotor 12 cannot be driven to rotate by the pressure difference between the liquid inlet 112 and the discharge port 113, the triangular rotor compressor 10 stops operating, the oil extracted by the pumping unit 1 and the mixed medium accumulated in the oil well oil pipe 30 are conveyed to the external transmission pipeline 60 from the high-pressure oil outlet 31, that is, the high-pressure oil and the mixed medium accumulated in the oil well oil pipe 30 are conveyed downstream to collect low-pressure associated gas, and the compression and recovery of the low-pressure associated.

In the above technical solution, when the pumping unit 1 is in the lower stroke, the pressure difference between the liquid inlet 112 and the discharge port 113 is utilized to realize the unpowered operation of the triangular rotor 12 of the triangular rotor compressor 10, so as to pump and recover the low-pressure associated gas in the oil well casing 20, without providing extra power for pumping and recovering the low-pressure associated gas, and complete the compression and recovery of the low-pressure associated gas in the oil well casing 20.

The main pipe body between the first branch pipe 51 and the second branch pipe 52 is provided with a check valve 40, and the communication direction of the check valve 40 is from the high-pressure oil outlet 31 to the external transmission pipeline 60.

The check valve 40 is arranged on the main pipe body between the first branch pipe 51 and the second branch pipe 52, the conducting direction of the main pipe is conducted from the high-pressure oil outlet 31 to the external transmission pipeline 60, the check valve 40 is arranged, in the lower stroke of the pumping unit, high-pressure oil is prevented from flowing back to the high-pressure oil outlet 31, the high-pressure oil can be conveyed to the oil inlet 121 on the cylinder body 11, the check valve 40 can stably and reliably realize one-way conduction and reverse stop of a medium, and the check valve 40 is convenient to arrange and maintain.

Of course, a ball valve may be disposed between the first and

second branch pipes

51, 52, and during the upper stroke of the pumping unit 1, the ball valve is opened to enable the high-pressure oil to be normally delivered from the high-pressure oil outlet 31 to the external delivery pipe 60, and during the lower stroke of the pumping unit 1, the ball valve is closed to enable the high-pressure oil to be delivered to the oil inlet 121 of the cylinder 11, and the ball valve may be replaced by an electromagnetic valve to implement the automatic connection and disconnection of the main pipe.

A gate valve 45 is provided on the main pipe in parallel with the check valve 40.

The pipeline of the check valve 40 connected with the gate valve 45 in parallel is respectively provided with a first ball valve 41 and a second ball valve 42.

A third ball valve 44 is arranged on a pipeline of the air inlet 111 communicated with the low-pressure air outlet 21 of the oil well casing 20, and a fourth ball valve 44 is arranged on the second branch pipe 52.

Under the condition that the three-lobe rotor compressor 10 needs to be changed or maintained, that is to say, the operation of the three-lobe rotor compressor 10 is stopped, in order to avoid influencing the normal collection and transportation of the oil liquid of the pumping unit 1, the first, second and

third ball valves

41, 42 and 43 are closed, and the gate valve 45 is opened, so that the normal collection of the oil liquid is avoided being influenced, and the collected oil liquid can be normally transported to the outward transportation pipeline 60 through the high-pressure oil outlet 31 and the gate valve 45.

The air inlet 111 and the exhaust port 113 are disposed adjacent to each other and are located at one side of the cylinder 11, and the liquid inlet 112 is located at the other side of the cylinder 11.

An inner gear ring is arranged in the middle of the triangular rotor 12, a transmission shaft is arranged in the cylinder body 11, one end of the transmission shaft is located in a cavity of the cylinder body 11, a gear is arranged at the end of the transmission shaft, the other end of the transmission shaft is connected with a power unit, and the gear at one end of the transmission shaft is in meshing transmission with the inner gear ring of the triangular rotor 12.

Above-mentioned power unit can be the motor, gasoline engine or diesel engine power supply, and it is less to avoid the pressure differential of inlet 112 department and discharge port 113 department, and can't ensure the stable condition of retrieving of low pressure associated gas, and this application orders about the transmission shaft through setting up power unit and rotates, and the transmission shaft orders about the triangle rotor 12 rotation to this makes the low pressure associated gas can stably retrieve in the oil well sleeve pipe 20, and improves the recovery efficiency of low pressure associated gas in the oil well sleeve pipe 20.

The pipe orifice at one end of the main pipe is connected with the high-pressure oil outlet 31 of the oil well pipe 30, the pipe orifice at the other end is communicated with the external pipeline, and the conduction direction of the check valve 40 is that the high-pressure oil outlet 31 is conducted to the external pipeline 60.

The pipe orifice at the other end of the main pipe is communicated with the external pipeline 60, that is, the pipe orifice at the other end of the main pipe is communicated with the conveying pipeline of the downstream gas collecting station, so that the oil gas is mixed and conveyed to the gas collecting station to realize the recovery of the low-pressure associated gas in the oil well casing pipe 20.

The application also provides an oil field associated gas recovery method, which is used for an oil field associated gas recovery device, the oil field associated gas recovery device comprises a triangular rotor compressor 10, an air inlet 111, a liquid inlet 112 and a discharge port 113 are formed in a cylinder body 11 of the triangular rotor compressor 10, a triangular rotor 12 arranged in the cylinder body 11 rotates forwards and locks reversely, the triangular rotor 12 and the cylinder body 11 are matched to form independent first, second and third chambers, the air inlet 111 is communicated with a low-pressure gas outlet 21 of an oil well casing pipe 20, a high-pressure oil outlet 31 of the oil well oil pipe 30 is communicated with a main pipe, first and

second branch pipes

51 and 52 on the main pipe are respectively communicated with the liquid inlet 112 and the discharge port 113, and the conducting direction of the main pipe between the first and

second branch pipes

51 and 52 is conducted to an external transmission pipeline 60 through the high-pressure oil outlet 31;

when the pumping unit 1 connected with the oil well pipe 30 is in the down stroke, the method comprises the following steps:

step S1: the low-pressure associated gas in the oil well casing 20 enters the first chamber through the air inlet 111 of the delta-rotor compressor 10, the high-pressure oil of the output pipeline flows back to the liquid inlet 112 of the delta-rotor compressor 10 to enter the second chamber, and the delta-rotor 12 of the delta-rotor compressor 10 is driven to rotate by the pressure difference formed by the high pressure at the liquid inlet 112 and the low pressure at the discharge outlet 113 of the delta-rotor compressor 10;

step S2: the triangular rotor 12 of the triangular rotor compressor 10 rotates to enable the first cavity to be communicated with the liquid inlet 112, and high-pressure oil enters the first cavity to be mixed with low-pressure associated gas to form a mixed medium;

step S3: the triangular rotor 12 of the triangular rotor compressor 10 rotationally compresses the mixed medium in the first chamber;

step S4: the triangular rotor 12 of the triangular rotor compressor 10 rotates to make the first chamber communicate with the discharge port 113, and the mixed medium is conveyed into the oil well pipe 30 through the discharge port 113;

the pumping unit 1 is in the upstroke, the triangular rotor 12 of the triangular rotor compressor 10 isolates the air inlet 111, the liquid inlet 112 and the discharge port 113 two by two, the oil pressure at the liquid inlet 112 is equal to the pressure at the discharge port 131, the triangular rotor compressor 10 stops running, the oil liquid extracted by the pumping unit 1 and the mixed medium accumulated in the oil well oil pipe 30 are conveyed to the external transmission pipeline 60 from the high-pressure oil outlet 31, and the compression and recovery of the low-pressure associated gas in the oil well casing pipe 20 are completed.

A check valve 40 is arranged on the main pipe body between the first branch pipe 51 and the second branch pipe 52, and the conduction direction of the check valve 40 is from the high-pressure oil outlet 31 to the external transmission pipeline 60;

the step S1 further includes: the check valve 40 restricts the backflow of the high pressure oil of the outgoing line to the well tubing 30.

The oil liquid that the beam-pumping unit 1 was produced and the mixed medium that piles up in oil well oil pipe 30 are carried to defeated pipeline 60 outward from high-pressure oil export 31, include:

the oil extracted by the pumping unit 1 and the mixed medium accumulated in the oil pipe 30 of the oil well are delivered from the high-pressure oil outlet 31 to the external delivery pipeline 60 through the check valve 40.

The pressure difference of inlet 112 department and discharge port 113 department is utilized to this application, realizes the unpowered operation of the triangle rotor 12 of triangle rotor compressor 10 to carry out the suction to the low pressure associated gas in the oil well sleeve pipe 20 and retrieve, need not additionally to provide the power of carrying out the suction to the low pressure associated gas and retrieving, can accomplish the compression of natural gas in the oil well sleeve pipe and retrieve, reduce the recovery cost of associated gas in the oil well sleeve pipe by a wide margin.

The preferred embodiments and examples of the present application have been described in detail with reference to the accompanying drawings, but the present application is not limited to the embodiments and examples described above, and various changes can be made within the knowledge of those skilled in the art without departing from the concept of the present application.

Claims

1. The oilfield associated gas recovery method is characterized by being used for an oilfield associated gas recovery device, the oilfield associated gas recovery device comprises a triangular rotor compressor (10), an air inlet (111), a liquid inlet (112) and a discharge port (113) are formed in a cylinder body (11) of the triangular rotor compressor (10), a triangular rotor (12) arranged in the cylinder body (11) rotates in the forward direction and locks in the reverse direction, the triangular rotor (12) and the cylinder body (11) are matched to form independent first, second and third chambers, the air inlet (111) is communicated with a low-pressure gas outlet (21) of an oil well casing (20), a high-pressure oil outlet (31) of an oil well oil pipe (30) is communicated with a main pipe, first and second branch pipes (51 and 52) on the main pipe are respectively communicated with the liquid inlet (112) and the discharge port (113), and the first and second branch pipes (51 and (51, 113), 52) The conducting direction of the main pipe between the two pipes is from the high-pressure oil outlet (31) to the external pipeline (60);

when the pumping unit (1) connected with the oil well pipe (30) is in a down stroke, the method comprises the following steps:

step S1: low-pressure associated gas in the oil well casing (20) enters a first cavity through an air inlet (111) of the triangular rotor compressor (10), high-pressure oil of an output pipeline flows back to an liquid inlet (112) of the triangular rotor compressor (10) to enter a second cavity, and the triangular rotor (12) of the triangular rotor compressor (10) is driven to rotate by a pressure difference formed by high pressure at the liquid inlet (112) and low pressure at a discharge port (113) of the triangular rotor compressor (10);

step S2: the triangular rotor (12) of the triangular rotor compressor (10) rotates to enable the first cavity to be communicated with the liquid inlet (112), and high-pressure oil enters the first cavity and is mixed with low-pressure associated gas to form a mixed medium;

step S3: the triangular rotor (12) of the triangular rotor compressor (10) rotationally compresses the mixed medium in the first chamber;

step S4: the triangular rotor (12) of the triangular rotor compressor (10) rotates to enable the first chamber to be communicated with a discharge port (113), and the mixed medium is conveyed into an oil well pipe (30) through the discharge port (113);

the oil pumping unit (1) is in the upstroke, the triangular rotor (12) of the triangular rotor compressor (10) isolates the air inlet (111), the liquid inlet (112) and the discharge port (113) in pairs, the oil pressure at the liquid inlet (112) is equal to the pressure at the discharge port (131), the triangular rotor compressor (10) stops running, oil extracted by the oil pumping unit (1) and mixed media accumulated in the oil well oil pipe (30) are conveyed to an external pipeline (60) from the high-pressure oil outlet (31), and compression and recovery of low-pressure associated gas in the oil well casing pipe (20) are completed.

2. The oilfield associated gas recovery method according to claim 1, wherein a check valve (40) is arranged on the main pipe between the first branch pipe (51) and the second branch pipe (52), and the check valve (40) is communicated from the high-pressure oil outlet (31) to the external pipeline (60);

the step S1 further includes: the check valve (40) limits the high-pressure oil of the external pipeline (60) to flow back to the oil well oil pipe (30);

the fluid of beam-pumping unit (1) extraction and the mixed medium who piles up in oil well oil pipe (30) are carried to defeated pipeline (60) outward from high-pressure oil export (31), include:

the oil extracted by the oil pumping unit (1) and the mixed medium accumulated in the oil pipe (30) of the oil well are conveyed to an external conveying pipeline (60) from a high-pressure oil outlet (31) through a one-way valve (40).

3. The utility model provides an oil field associated gas recovery unit which characterized in that: the oil well oil pipe comprises a triangular rotor compressor (10), wherein a cylinder body (11) of the triangular rotor compressor (10) is provided with an air inlet (111), a liquid inlet (112) and a discharge port (113), a triangular rotor (12) arranged in the cylinder body (11) rotates in the positive direction and is locked in the reverse direction, the triangular rotor (12) and the cylinder body (11) are matched to form a first chamber, a second chamber and a third chamber which are independent, the air inlet (111) is communicated with a low-pressure air outlet (21) of an oil well casing pipe (20), a high-pressure oil outlet (31) of an oil well oil pipe (30) is communicated with a main pipe, a first branch pipe (51) and a second branch pipe (52) on the main pipe are respectively communicated with the liquid inlet (112) and the discharge port (113), and the conducting direction of the main pipe between the first branch pipe (51) and the second branch pipe (52) is conducted from the;

the pumping unit (1) connected with the oil well oil pipe (30) is in a down stroke, the triangular rotor compressor (10) performs suction compression on low-pressure associated gas in the oil well casing pipe (20) and mixes the low-pressure associated gas with high-pressure oil at a high-pressure oil outlet (31) to form a mixed medium, and the mixed medium is conveyed into the oil well oil pipe (30) through the discharge port (113);

and when the oil pumping unit (1) is in an upper stroke, oil extracted from the oil well oil pipe (30) and mixed media accumulated in the oil well oil pipe (30) are conveyed to an external conveying pipeline (60) from a high-pressure oil outlet (31), and compression and recovery of low-pressure associated gas in the oil well casing (20) are completed.

4. The oilfield associated gas recovery device of claim 3, wherein: the main pipe is provided with a check valve (40) between the first branch pipe (51) and the second branch pipe (52), and the communication direction of the check valve (40) is from the high-pressure oil outlet (31) to the external pipeline (60).

5. The oilfield associated gas recovery device of claim 3, wherein: and the main pipe is provided with a gate valve (45) which is connected with the one-way valve (40) in parallel.

6. The oilfield associated gas recovery device of claim 5, wherein: and a first ball valve (41) and a second ball valve (42) are respectively arranged on a pipeline which is connected with the check valve (40) and the gate valve (45) in parallel.

7. The oilfield associated gas recovery device of claim 3, wherein: a third ball valve (43) is arranged on a pipeline of the air inlet (111) communicated with the low-pressure air outlet (21) of the oil well casing (20), and a fourth ball valve (44) is arranged on the second branch pipe (52).

8. The oilfield associated gas recovery device of claim 3, wherein: the air inlet (111) and the discharge port (113) are arranged adjacently and positioned at one side of the cylinder body (11), and the liquid inlet (112) is positioned at the other side of the cylinder body (11).

9. The oilfield associated gas recovery device of claim 3, wherein: the hydraulic cylinder is characterized in that an inner gear ring is arranged in the middle of the triangular rotor (12), a transmission shaft is arranged in the cylinder body (11), one end of the transmission shaft is located in a cavity of the cylinder body (11), a gear is arranged at the end of the transmission shaft, the other end of the transmission shaft is connected with a power unit, and the gear at one end of the transmission shaft is in meshing transmission with the inner gear ring of the triangular rotor (12).

10. The oilfield associated gas recovery device of claim 4, wherein: and a pipe orifice at one end of the main pipe is connected with a high-pressure oil outlet (31) of the oil well oil pipe (30), and a pipe orifice at the other end of the main pipe is communicated with an external pipeline (60).