Oil and gas gathering and transporting treatment system and treatment process for fireflooding oil field

Abstract

The invention provides a fireflooding oil field oil gas gathering and transporting treatment system and a treatment process, the fireflooding oil field oil gas gathering and transporting treatment system comprises an oil gas collecting unit, the oil gas collecting unit is provided with an oil collecting pipeline and a gas collecting pipeline which are connected with a Christmas tree, the oil collecting pipeline is connected with an oil collecting manifold, and the gas collecting pipeline is connected with a gas collecting manifold and a watering system; a first communicating pipeline is connected between the oil collecting pipeline and the gas collecting pipeline; and the oil gas treatment unit is provided with a gas-liquid separator connected with the oil collecting manifold and a production separator connected with the gas collecting manifold, and a second communication pipeline is connected between an inlet of the gas-liquid separator and an inlet of the production separator. According to the invention, the problems of high investment cost and large occupied area caused by the need of independently arranging a watering pipeline and more gas-liquid separation treatment equipment in the gathering and transportation treatment process of the fireflooding oil field are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas gathering and transportation processing, and particularly to an oil and gas gathering and transportation processing system and a processing technology for a fire flooding oilfield. Background Art

[0002] The development of heavy oil oilfields generally includes three production methods: cyclic steam stimulation and steam drive production, steam assisted gravity drainage (SAGD), and fire flooding production. The fire flooding production process ignites the crude oil in the underground oil reservoir through an ignition device at the bottom of the wellhead, and at the same time injects air into the oil reservoir. Through the combustion of the crude oil in the underground oil reservoir, heat is released to continuously reduce the viscosity of the heavy oil, and the heavy oil is produced by a pumping unit. The crude oil recovery rate can reach about 60%. The fire flooding production process is suitable for the secondary development of old areas of heavy oil oilfields. Fire flooding is the earliest thermal oil recovery technology used for developing heavy oil. With the development of fire flooding oilfield development technology, the oil and gas processing technology in fire flooding oilfield stations has become increasingly important. The current conventional oil and gas gathering and transportation processing technology has the following problems when directly applied to fire flooding oilfields:

[0003] 1. For the low temperature at the wellhead of the production well, gathering and transportation methods such as water blending in series gathering and wellhead heating in series gathering can be adopted. When the temperature at the production wellhead is high, single pipe in series gathering can be adopted. However, in the early stage of fire flooding, water blending or heating gathering and transportation methods are used, and after the fire flooding becomes effective, the water blending pipelines and heating equipment are no longer used, resulting in idle equipment and wasted investment.

[0004] 2. For the separate transportation of casing gas and tubing fluid in fire flooding gathering and transportation, according to the requirements of the "Design Code for Oil and Gas Gathering and Transportation in Oilfields" (GB50350-2015), "the number of continuously operating oil and gas separators shall not be less than 2 sets". At least 2 gas-liquid separators need to be set for the tubing fluid entering the station for separation, and 1 production separator needs to be set for the casing gas for gas-liquid separation.

[0005] 3. For a large amount of liquid carried by the gas phase, a condensation separation process of an air cooler / water-cooled heat exchanger + oil remover is generally adopted. However, for the heavy oil with high viscosity produced by fire flooding development, there is a problem that the crude oil adheres to the heat exchange tubes of the air cooler or heat exchanger, resulting in blockage. Summary of the Invention

[0006] The purpose of the present invention is to provide an oil and gas gathering and transportation processing system and a processing technology for a fire flooding oilfield, which solve the problems of high investment cost and large floor area caused by the need to separately set water blending pipelines and a large number of gas-liquid separation processing equipment in the process of the fire flooding oilfield gathering and transportation processing technology.

[0007] On the one hand, the present invention provides an oil and gas gathering and transportation processing system for a fire flooding oilfield, which includes:

[0008] An oil and gas collection unit, having an oil collection pipeline and a gas collection pipeline connected to a Christmas tree, the oil collection pipeline being connected to an oil collection manifold, the gas collection pipeline being connected to a gas collection manifold and a water blending system, and a first communication pipeline being connected between the oil collection pipeline and the gas collection pipeline;

[0009] An oil and gas treatment unit, having a gas-liquid separator connected to the oil collection manifold and a production separator connected to the gas collection manifold, and a second communication pipeline being connected between the inlet of the gas-liquid separator and the inlet of the production separator.

[0010] In a preferred embodiment of the present invention, the gas phase outlet of the gas-liquid separator and the gas phase outlet of the production separator are connected to a secondary separator through a gas phase pipeline.

[0011] In a preferred embodiment of the present invention, a cooling device is provided on the gas phase pipeline, the cooling device having a cooling water casing sleeved on the gas phase pipeline, and cooling water flowing through the cooling water casing.

[0012] In a preferred embodiment of the present invention, the liquid phase outlet of the gas-liquid separator and the liquid phase outlet of the production separator are connected to a crude oil dehydration system through a liquid phase pipeline.

[0013] In a preferred embodiment of the present invention, the discharge outlet of the gas-liquid separator and the discharge outlet of the production separator are connected to a venting device through a venting pipeline.

[0014] In a preferred embodiment of the present invention, the liquid phase outlet of the gas-liquid separator, the liquid phase outlet of the production separator and the liquid phase outlet of the secondary separator are connected to a crude oil dehydration system through a liquid phase pipeline.

[0015] In a preferred embodiment of the present invention, the discharge outlet of the gas-liquid separator, the discharge outlet of the production separator and the discharge outlet of the secondary separator are connected to a venting device through a venting pipeline.

[0016] In a preferred embodiment of the present invention, the gas phase outlet of the secondary separator is connected to a gas treatment system.

[0017] In a preferred embodiment of the present invention, safety valves are provided at the discharge outlet of the gas-liquid separator, the discharge outlet of the production separator and the discharge outlet of the secondary separator.

[0018] In a preferred embodiment of the present invention, gas phase self-operated regulating valves are provided at the gas phase outlet of the gas-liquid separator, the gas phase outlet of the production separator and the gas phase outlet of the secondary separator.

[0019] In a preferred embodiment of the present invention, liquid-phase electric control valves are provided at the liquid-phase outlets of the gas-liquid separator, the production separator, and the secondary separator.

[0020] In a preferred embodiment of the present invention, pressure transmitters, first temperature transmitters, first check valves, and sampling stop valves are provided on both the oil gathering pipeline and the gas gathering pipeline.

[0021] In a preferred embodiment of the present invention, a second check valve and a first on-off valve are provided on the first connecting pipeline.

[0022] In a preferred embodiment of the present invention, a second on-off valve is provided on the oil gathering pipeline, and the second on-off valve is located on the oil gathering pipeline between the oil gathering header and the first connecting pipeline; a third on-off valve is provided on the gas gathering pipeline, and the third on-off valve is located on the gas gathering pipeline between the Christmas tree and the first connecting pipeline.

[0023] In a preferred embodiment of the present invention, second temperature transmitters are provided at both ends of the gas pipeline in the cooling device.

[0024] In a preferred embodiment of the present invention, a cooling water channel surrounding the gas pipeline is formed in the cooling water jacket, and the opposite ends of the cooling water channel are respectively connected to a cooling water inlet pipe and a cooling water outlet pipe.

[0025] In a preferred embodiment of the present invention, a third connecting pipeline is connected between the cooling water inlet pipe and the cooling water outlet pipe, and a fourth on-off valve is provided on the third connecting pipeline.

[0026] On the other hand, the present invention also provides a process for gathering, transporting, and processing oil and gas in a fire flooding oilfield, which includes:

[0027] In the initial stage of fire flooding oilfield development, a part of the gas gathering pipeline connected to the Christmas tree is closed and used as a water injection pipeline, and water is injected into the oil gathering pipeline through the first connecting pipeline connected between the gas gathering pipeline and the oil gathering pipeline to increase the temperature of the wellhead;

[0028] After the fire flooding becomes effective, the first connecting pipeline is cut off, and the gas gathering pipeline is opened for normal gas gathering operation.

[0029] In a preferred embodiment of the present invention, the process for gathering, transporting, and processing oil and gas in the fire flooding oilfield further includes:

[0030] When the production separator for processing the gas collected by the gas gathering pipeline needs to be overhauled, the gas is introduced into the gas-liquid separator for processing through the second connecting pipeline connected between the inlet of the production separator and the inlet of the gas-liquid separator;

[0031] When the gas-liquid separator for treating the liquid collected by the oil gathering pipeline needs to be overhauled, the liquid is introduced into the production separator through the second communication pipeline for treatment.

[0032] In a preferred embodiment of the present invention, the oil-gas gathering and transportation treatment process for the fire flooding oilfield further includes:

[0033] A cooling device is arranged on the gas pipeline connected to the gas phase outlet of the production separator and the gas phase outlet of the gas-liquid separator. A cooling water channel is formed in the cooling device, which surrounds the gas pipeline outside and can cool the gas in the gas pipeline.

[0034] Compared with the prior art, the technical solution of the present invention has the following characteristics and advantages:

[0035] 1. A first communication pipeline is connected between the oil gathering pipeline and the gas gathering pipeline in the present invention. During the early stage of fire flooding, the gas gathering pipeline is used as a water injection pipeline through the first communication pipeline, solving the problem of inadaptability to the conventional gathering and transportation process caused by the low temperature of the oil production wellhead in the early stage of fire flooding and the high temperature of the oil production wellhead after the reduction of fire flooding.

[0036] 2. A second communication pipeline is connected between the inlet of the production separator and the inlet of the gas-liquid separator in the present invention. Through the second communication pipeline, the two are used as backups for each other, solving the problems of a large number of gas-liquid separators in the station, high investment, and large floor area.

[0037] 3. A cooling water sleeve is arranged outside the gas pipeline in the present invention. The gas is cooled by the cooling water in the cooling water sleeve, thereby solving the problem of a large amount of liquid carried by the gas treatment system and affecting the operation of the gas treatment device. Brief Description of the Drawings

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings. In the drawings:

[0039] The drawings described herein are only for illustrative purposes and are not intended to limit the scope of the present disclosure in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only schematic and are used to help understand the present invention, rather than specifically limiting the shapes and proportional dimensions of the components of the present invention. Those skilled in the art can choose various possible shapes and proportional dimensions according to the specific situation to implement the present invention under the teaching of the present invention.

[0040] Figure 1 It is a schematic structural diagram of the oil and gas collection unit described in the present invention;

[0041] Figure 2 It is a schematic structural diagram of the oil and gas treatment unit described in the present invention;

[0042] Figure 3 It is a schematic structural diagram of the cooling device described in the present invention.

[0043] Explanation of the reference numerals in the attached drawings:

[0044] 10. Oil and gas collection unit; 11. Oil collection pipeline; 12. Gas collection pipeline; 13. Water injection system; 14. Pressure transmitter; 15. First temperature transmitter; 16. First check valve; 17. Sampling stop valve; 18. Second switching valve; 19. Third switching valve;

[0045] 20. Oil and gas treatment unit; 21. Gas-liquid separator; 22. Production separator; 23. Gas phase pipeline; 231. Self-operated regulating valve; 24. Secondary separator; 25. Liquid phase pipeline; 251. Liquid phase electric regulating valve; 26. Vent pipeline; 261. Safety valve;

[0046] 30. Christmas tree; 31. Oil collection manifold; 32. Gas collection manifold; 33. Crude oil dehydration system; 34. Venting device; 35. Gas treatment system;

[0047] 40. First connecting pipeline; 41. Second check valve; 42. First switching valve;

[0048] 50. Second connecting pipeline;

[0049] 60. Cooling device; 61. Cooling water jacket; 62. Cooling water channel; 63. Second temperature transmitter; 64. Cooling water inlet pipe; 65. Cooling water outlet pipe; 66. Third connecting pipeline; 661. Fourth switching valve; 67. Third temperature transmitter; 68. Fifth switching valve. Detailed implementation manners

[0050] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0051] It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only embodiments.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this invention belongs. The terms used herein in the specification of this invention are only for the purpose of describing specific embodiments and are not intended to limit the invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0053] Embodiment 1:

[0054] As Figures 1 to 3 shown, the present invention provides a gas-oil gathering and treating system for a fire flooding oilfield, which includes: an oil-gas collection unit 10, having an oil gathering pipeline 11 and a gas gathering pipeline 12 connected to a Christmas tree 30, the oil gathering pipeline 11 being connected to an oil gathering manifold 31, the gas gathering pipeline 12 being connected to a gas gathering manifold 32 and a water blending system 13, and a first communication pipeline 40 being connected between the oil gathering pipeline 11 and the gas gathering pipeline 12; an oil-gas treatment unit 20, having a gas-liquid separator 21 connected to the oil gathering manifold 31 and a production separator 22 connected to the gas gathering manifold 32, and a second communication pipeline 50 being connected between the inlet of the gas-liquid separator 21 and the inlet of the production separator 22.

[0055] The gas-oil gathering and treating system for a fire flooding oilfield according to the present invention can be applied to an oilfield adopting a fire flooding oil production process. While meeting normal production requirements, it overcomes various problems existing in the application of conventional gathering and treating processes in fire flooding development, and can achieve good economic and social benefits.

[0056] A first communication pipeline 40 is connected between the oil gathering pipeline 11 and the gas gathering pipeline 12 in the present invention. During the early stage of fire flooding, the gas gathering pipeline 12 is used as a water blending pipeline through the first communication pipeline 40 to solve the problem of inadaptability to the conventional gathering process caused by the low temperature of the oil production wellhead in the early stage of fire flooding and the high temperature of the oil production wellhead after the reduction of fire flooding.

[0057] A second communication pipeline 50 is connected between the inlet of the production separator 22 and the inlet of the gas-liquid separator 21 in the present invention. Through the second communication pipeline 50, the two are used as backups for each other, solving the problems of a large number of gas-liquid separators 21 in the station, high investment and large floor area.

[0058] The pipeline connection structure of the oil and gas collection unit 10, the pipeline connection structure of the oil and gas treatment unit 20, and the connection relationship between the two will be further described in detail below.

[0059] First, one end of the oil and gas collection unit 10 in the present invention is connected to the Christmas tree 30, that is, connected to the oil well, and is used to collect and transport the oil liquid and gas generated in the oil well; the other end of the oil and gas collection unit 10 is connected to the oil gathering manifold 31 and the gas gathering manifold 32, and the oil liquid collected from the Christmas tree 30 is converged into the oil gathering manifold 31, and at the same time, the gas collected from the Christmas tree 30 is converged into the gas gathering manifold 32.

[0060] Specifically, as Figure 1 shown, the oil and gas collection unit 10 includes an oil gathering pipeline 11 and a gas gathering pipeline 12. The two ends of the oil gathering pipeline 11 are respectively connected to the Christmas tree 30 and the oil gathering manifold 31, and are used to transport the oil liquid produced in the oil pipe to the oil gathering manifold 31. The two ends of the gas gathering pipeline 12 are respectively connected to the Christmas tree 30 and the gas gathering manifold 32, and are used to transport the gas produced in the casing to the gas gathering manifold 32.

[0061] Furthermore, a first communication pipeline 40 is connected between the oil gathering pipeline 11 and the gas gathering pipeline 12, and a water blending system 13 is connected to the gas gathering pipeline 12 between the first communication pipeline 40 and the gas gathering manifold 32. In the initial stage of the development of the fire flooding oil field, the temperature of the oil production wellhead is low (10°C - 20°C). In order to prevent the oil liquid in the oil gathering pipeline 11 from solidifying, it is necessary to blend water (higher temperature water) into the oil gathering pipeline 11; in the initial stage of the development of the fire flooding oil field, the gas gathering pipeline 12 between the first communication pipeline 40 and the Christmas tree 30 is closed, the first communication pipeline 40 is opened, and the gas gathering pipeline 12 between the first communication pipeline 40 and the water blending system 13 is used as a water blending pipeline. At this time, a part of the gas gathering pipeline 12 and the first communication pipeline 40 form a water blending pipeline connected to the oil gathering pipeline 11, which is used to transport high-temperature water to the oil gathering pipeline 11, and the water blending system 13 in the station can supply water for water blending in gathering and transportation (the temperature is about 60 degrees).

[0062] In an actual oil and gas gathering and transportation processing workstation, the fire flooding oil field oil and gas gathering and transportation processing system of the present invention has a large number of oil gathering pipelines 11 and gas gathering pipelines 12. Each group of parallel oil gathering pipelines 11 and gas gathering pipelines 12 adopts the above-mentioned setting method. A plurality of oil gathering pipelines 11 are all connected to the oil gathering manifold 31 to realize the convergence of oil liquid, and a plurality of gas gathering pipelines 12 are all connected to the gas gathering manifold 32 to realize the convergence of gas.

[0063] According to an embodiment of the present invention, as Figure 1As shown in the figure, pressure transmitters 14, first temperature transmitters 15, first check valves 16, and sampling stop valves 17 are provided on both the oil gathering pipeline 11 and the gas gathering pipeline 12. The two pressure transmitters 14 are respectively used to detect and monitor the pressure on the oil gathering pipeline 11 and the pressure on the gas gathering pipeline 12; the two first temperature transmitters 15 are respectively used to detect and monitor the temperature inside the oil gathering pipeline 11 and the temperature inside the gas gathering pipeline 12; the two first check valves 16 are respectively used to prevent the oil liquid in the oil gathering pipeline 11 from flowing back and the gas in the gas gathering pipeline 12 from flowing back; the two sampling stop valves 17 are respectively used to sample the oil liquid in the oil gathering pipeline 11 and the gas in the gas gathering pipeline 12.

[0064] According to an embodiment of the present invention, as Figure 1 shown in the figure, a second check valve 41 and a first on-off valve 42 are provided on the first communication pipeline 40. The second check valve 41 is used to block the liquid from flowing back inside the first communication pipeline 40, so as to avoid the oil liquid in the oil gathering pipeline 11 entering the gas gathering pipeline 12 through the first communication pipeline 40 during water-mixed gathering and transportation; the first on-off valve 42 is used to control the opening and closing of the first communication pipeline 40. In this embodiment, the first on-off valve 42 is a gate valve.

[0065] According to an embodiment of the present invention, as Figure 1 shown in the figure, a second on-off valve 18 is provided on the oil gathering pipeline 11, and the second on-off valve 18 is located on the oil gathering pipeline 11 between the oil gathering manifold 31 and the first communication pipeline 40; a third on-off valve 19 is provided on the gas gathering pipeline 12, and the third on-off valve 19 is located on the gas gathering pipeline 12 between the Christmas tree 30 and the first communication pipeline 40. The second on-off valve 18 is used to control the opening and closing of the oil gathering pipeline 11. In this embodiment, the second on-off valve 18 is a gate valve; the third on-off valve 19 is used to control the opening and closing of the gas gathering pipeline 12. In this embodiment, the third on-off valve 19 is a ball valve.

[0066] During the specific working process of the oil and gas collection unit 10 of the present invention, in the initial stage of the development of the fire flooding oilfield, the third on-off valve 19 (ball valve) on the gas gathering pipeline 12 is closed, the first on-off valve 42 (gate valve) on the first communication pipeline 40 is opened, the water mixing system 13 in the station is started, and water is mixed into the oil gathering pipeline 11 through the gas gathering pipeline 12 and the first communication pipeline 40; after the fire flooding becomes effective, the wellhead temperature becomes higher and the gas volume becomes larger. The first on-off valve 42 (gate valve) on the first communication pipeline 40 is closed, the third on-off valve 19 (ball valve) on the gas gathering pipeline 12 is opened, and the gas gathering pipeline 12 conducts normal gas collection and transportation operations.

[0067] Secondly, as Figure 2As shown in the figure, one end of the oil and gas treatment unit 20 in the present invention is connected to both the oil collecting manifold 31 and the gas collecting manifold 32 at the same time. The oil and gas collected and converged in the oil and gas collection unit 10 can enter the oil and gas treatment unit 20 for oil and gas two-phase separation treatment. The other end of the oil and gas treatment unit 20 is connected to the crude oil dehydration system 33, the gas treatment system 35, and the venting device 34. The gas and oil separated by the oil and gas treatment system 35 can enter the gas treatment system 35 and the crude oil dehydration system 33 for further treatment, or be vented through the venting device 34.

[0068] Specifically, as Figure 2 shown in the figure, the oil collecting manifold 31 is connected to the inlet of the gas-liquid separator 21. The oil converged in the oil collecting manifold 31 can enter the gas-liquid separator 21 for gas-liquid separation treatment. The gas collecting manifold 32 is connected to the inlet of the production separator 22. The gas converged in the gas collecting manifold 32 can enter the production separator 22 to remove the liquid phase.

[0069] Furthermore, a second communication pipeline 50 is connected between the inlet of the production separator 22 and the inlet of the gas-liquid separator 21, so that the production separator 22 and the gas-liquid separator 21 can be used as spares for each other through the second communication pipeline 50. When the production separator 22 needs to be overhauled, the inlet of the production separator 22 is closed, and the second communication pipeline 50 is opened. The gas in the gas collecting manifold 32 and the oil in the oil collecting manifold 31 enter the gas-liquid separator 21 together through the second communication pipeline 50 for gas-liquid two-phase separation. When the gas-liquid separator 21 needs to be overhauled, the inlet of the gas-liquid separator 21 is closed, and the second communication pipeline 50 is opened. The oil in the oil collecting manifold 31 and the gas in the gas collecting manifold 32 enter the production separator 22 together through the second communication pipeline 50 for gas-liquid two-phase separation.

[0070] According to an embodiment of the present invention, as Figure 2 shown in the figure, the gas-liquid separator 21 has a gas phase outlet and a liquid phase outlet. Among them, the gas phase outlet of the gas-liquid separator 21 is connected to the secondary separator 24 through the gas phase pipeline 23, and the liquid phase outlet of the gas-liquid separator 21 is connected to the crude oil dehydration system 33 through the liquid phase pipeline 25. The production separator 22 has a gas phase outlet and a liquid phase outlet. Among them, the gas phase outlet of the production separator 22 is connected to the secondary separator 24 through the gas phase pipeline 23, and the liquid phase outlet of the production separator 22 is connected to the crude oil dehydration system 33 through the liquid phase pipeline 25.

[0071] The secondary separator 24 is used for further gas-liquid two-phase separation treatment of the gas phase (gas) separated by the gas-liquid separator 21 and the production separator 22, so as to improve the removal effect of the liquid phase in the gas. The crude oil dehydration system 33 can dehydrate the liquid phase (oil) separated by the gas-liquid separator 21 and the production separator 22.

[0072] According to an embodiment of the present invention, as Figure 2 shown, the secondary separator 24 has a gas phase outlet and a liquid phase outlet. Among them, the gas phase outlet of the secondary separator 24 is connected to the gas treatment system 35, and the liquid phase outlet of the secondary separator 24 is connected to the crude oil dehydration system 33 through the liquid phase pipeline 25.

[0073] The gas treatment system 35 can further process the gas phase (gas) separated by the secondary separator 24 to improve the utilization efficiency of resources; the crude oil dehydration system 33 can dehydrate the liquid phase (oil liquid) separated by the secondary separator 24.

[0074] According to an embodiment of the present invention, as Figure 2 shown, the gas-liquid separator 21, the production separator 22, and the secondary separator 24 all have a discharge outlet. The discharge outlet of the gas-liquid separator 21, the discharge outlet of the production separator 22, and the discharge outlet of the secondary separator 24 are connected to the venting device 34 through the venting pipeline 26.

[0075] Under accident conditions, such as downstream pipeline blockage, valve misclosure, fire, etc., the gas in the gas-liquid separator 21, the production separator 22, and the secondary separator 24 can be discharged into the atmosphere through the venting pipeline 26 via the venting device 34 to ensure the safety of the entire oil and gas treatment unit 20 during the production process.

[0076] According to an embodiment of the present invention, as Figure 2 shown, gas phase self-operated regulating valves 231 are provided at the gas phase outlets of the gas-liquid separator 21, the production separator 22, and the secondary separator 24. Two gas phase self-operated regulating valves 231 at the gas phase outlets of the gas-liquid separator 21 and the production separator 22 are arranged on the gas phase pipeline 23. These two gas phase self-operated regulating valves 231 can adjust the opening degrees of the gas phase outlets of the gas-liquid separator 21 and the production separator 22 respectively according to the actual operating environment; one gas phase self-operated regulating valve 231 at the gas phase outlet of the secondary separator 24 is arranged on the pipeline between the secondary separator 24 and the gas treatment system 35, and this gas phase self-operated regulating valve 231 can adjust the opening degree of the gas phase outlet of the secondary separator 24 according to the actual operating environment

[0077] According to an embodiment of the present invention, as Figure 2As shown, liquid-phase electric control valves 251 are provided at the liquid-phase outlets of the gas-liquid separator 21, the production separator 22, and the secondary separator 24. The three liquid-phase electric control valves 251 are arranged on the liquid-phase pipeline 25 and can adjust the opening degrees of the liquid-phase outlets of the gas-liquid separator 21, the production separator 22, and the secondary separator 24 respectively according to the actual operating environment.

[0078] According to an embodiment of the present invention, as Figure 2 shown, safety valves 261 are provided at the discharge outlets of the gas-liquid separator 21, the production separator 22, and the secondary separator 24. The three safety valves 261 are arranged on the vent pipeline 26 and can control the opening and closing of the vent pipeline 26 according to the actual operating environment.

[0079] According to an embodiment of the present invention, as Figure 2 and Figure 3 shown, a cooling device 60 is provided on the gas-phase pipeline 23. The cooling device 60 has a cooling water sleeve 61 sleeved on the gas-phase pipeline 23, and cooling water passes through the cooling water sleeve 61.

[0080] In the present invention, a cooling water sleeve 61 is provided outside the gas-phase pipeline 23, and the gas in the gas-phase pipeline 23 is cooled by the cooling water in the cooling water sleeve 61, thereby solving the problem that the gas treatment system 35 carries a large amount of liquid, which affects the operation of the gas treatment system 35.

[0081] Specifically, as Figure 3 shown, the cooling water sleeve 61 is sleeved outside the gas-phase pipeline 23, and an annular cooling water channel 62 is formed between the two. The flow direction of the cooling water in the cooling water channel 62 is opposite to the flow direction of the gas in the gas-phase pipeline 23. The opposite ends of the cooling water channel 62 are respectively connected with a cooling water inlet pipe 64 and a cooling water outlet pipe 65. In a specific embodiment of the present invention, the length of the cooling water sleeve 61 is set to 20 m. Cooling water with a temperature of 20 °C passes through the cooling water inlet pipe 64. After passing through the cooling water channel 62, the temperature of the cooling water entering the cooling water outlet pipe 65 is 40 °C. The temperature of the gas in the gas-phase pipeline 23 drops from 60 °C to 45 °C after passing through the cooling water sleeve 61. At the same time, condensate is precipitated in the gas-phase pipeline 23 and then enters the secondary separator 24 to remove the condensate.

[0082] According to an embodiment of the present invention, as Figure 3 shown, second temperature transmitters 63 are respectively provided at both ends of the gas-phase pipeline 23 where the cooling device 60 is located. The two second temperature transmitters 63 provided at both ends of the cooling water sleeve 61 can respectively detect and monitor the front and rear temperatures of the gas in the gas-phase pipeline 23.

[0083] According to an embodiment of the present invention, Figure 3 As shown, a third communication pipeline 66 is connected between the cooling water inlet pipe 64 and the cooling water outlet pipe 65, and a fourth on-off valve 661 is provided on the third communication pipeline 66. The temperature of the cooling water entering the cooling water inlet pipe 64 is adjusted through the third communication pipeline 66; when the temperature in the cooling water inlet pipe 64 is lower than the freezing point of the crude oil, the opening of the fourth on-off valve 661 is opened or increased, so that part of the cooling water flowing out of the cooling water outlet pipe 65 flows into the cooling water inlet pipe 64, thereby making the temperature of the cooling water entering higher than the freezing point of the crude oil, and avoiding the solidification of the oil liquid in the gas pipeline 23 due to the too low temperature of the cooling water entering the cooling water inlet pipe 64.

[0084] According to an embodiment of the present invention, as Figure 3 shown, fifth temperature transmitters are provided on both the cooling water inlet pipe 64 and the cooling water outlet pipe 65. The fifth temperature transmitter on the cooling water inlet pipe 64 can detect and monitor the temperature of the cooling water entering; the fifth temperature transmitter on the cooling water outlet pipe 65 can detect and monitor the temperature of the cooling water flowing out.

[0085] Embodiment two:

[0086] As Figures 1 to 3 shown, the present invention also provides a process for gathering, transporting and processing oil and gas in a fire flooding oilfield, which includes:

[0087] S1: In the initial stage of the development of the fire flooding oilfield, part of the gas gathering pipeline 12 connected to the Christmas tree 30 is closed and used as a water injection pipeline, and water is injected into the oil gathering pipeline 11 through the first communication pipeline 40 connected between the gas gathering pipeline 12 and the oil gathering pipeline 11 to increase the temperature of the wellhead;

[0088] S2: After the fire flooding becomes effective, the first communication pipeline 40 is cut off, and the gas gathering pipeline 12 is opened for normal gas gathering operations.

[0089] The process for gathering, transporting and processing oil and gas in the fire flooding oilfield described in the present invention uses the gas gathering pipeline 12 as a water injection pipeline in the early stage of fire flooding, and solves the problem of inadaptability to the conventional gathering and transportation process caused by the low temperature of the oil production wellhead in the early stage of fire flooding and the high temperature of the oil production wellhead after the fire flooding is reduced.

[0090] Specifically, in step S1, as Figure 1 shown, in the initial stage of the development of the fire flooding oilfield, the temperature of the oil production wellhead is low (10°C - 20°C). The third on-off valve 19 (ball valve) on the gas gathering pipeline 12 is closed, and the first on-off valve 42 (gate valve) on the first communication pipeline 40 is opened. The gas gathering pipeline 12 is used as the water injection pipeline in the early stage. The water (60°C) in the water injection system 13 in the station is injected into the oil gathering pipeline 11 through the gas gathering pipeline 12 and the first communication pipeline 40 to realize water injection and oil gathering. The temperature of the oil liquid produced by the oil pipe in the oil gathering pipeline 11 is 3°C - 5°C higher than the freezing point.

[0091] In step S2, after the fire flooding becomes effective, the wellhead temperature becomes higher (40°C - 50°C) and the gas volume becomes larger. The gathering pipeline 11 meets the requirements of gathering and transportation without heating. The first shut-off valve 42 on the first connecting pipeline 40 is closed, and the third shut-off valve 19 on the gas gathering pipeline 12 is opened. The water injection pipeline is switched to use the gas gathering pipeline 12.

[0092] According to an embodiment of the present invention, as Figure 2 shown, the oil and gas gathering and transportation treatment process for a fire flooding oilfield further includes: when the production separator 22 for treating the gas collected by the gas gathering pipeline 12 needs to be overhauled, the gas is introduced into the gas-liquid separator 21 for treatment through the second connecting pipeline 50 connected between the inlet of the production separator 22 and the inlet of the gas-liquid separator 21; when the gas-liquid separator 21 for treating the liquid collected by the gathering pipeline 11 needs to be overhauled, the liquid is introduced into the production separator 22 for treatment through the second connecting pipeline 50.

[0093] In the oil and gas gathering and transportation treatment process for a fire flooding oilfield of the present invention, the production separator 22 and the gas-liquid separator 21 are backup for each other, solving the problems of a large number of gas-liquid separators 21 in the station, high investment, and large floor area.

[0094] Specifically, when the production separator 22 needs to be overhauled, the inlet of the production separator 22 is closed, the second connecting pipeline 50 is opened, and the gas in the gas gathering header 32 enters the gas-liquid separator 21 together with the oil in the oil gathering header 31 through the second connecting pipeline 50 for gas-liquid two-phase separation; when the gas-liquid separator 21 needs to be overhauled, the inlet of the gas-liquid separator 21 is closed, the second connecting pipeline 50 is opened, and the oil in the oil gathering header 31 enters the production separator 22 together with the gas in the gas gathering header 32 through the second connecting pipeline 50 for gas-liquid two-phase separation.

[0095] According to an embodiment of the present invention, as Figure 3 shown, the oil and gas gathering and transportation treatment process for a fire flooding oilfield further includes: a cooling device 60 is provided on the gas pipeline 23 connected to the gas phase outlet of the production separator 22 and the gas phase outlet of the gas-liquid separator 21. A cooling water channel 62 is formed in the cooling device 60, which surrounds the gas pipeline 23 outside and can cool the gas in the gas pipeline 23.

[0096] In the oil and gas gathering and transportation treatment process for a fire flooding oilfield of the present invention, a cooling water casing 61 is provided outside the gas pipeline 23, and the gas in the gas pipeline 23 is cooled by the cooling water in the cooling water casing 61, thereby solving the problem that the gas treatment system 35 carries a large amount of liquid, which affects the operation of the gas treatment system 35.

[0097] Specifically, the cooling water sleeve 61 is sleeved outside the gas pipeline 23, and an annular cooling water channel 62 is formed therebetween. The flowing direction of the cooling water in the cooling water channel 62 is opposite to that of the gas in the gas pipeline 23. The opposite ends of the cooling water channel 62 are respectively connected with a cooling water inlet pipe 64 and a cooling water outlet pipe 65. The cooling water in the cooling water channel 62 exchanges heat with the gas in the gas pipeline 23, the gas in the gas pipeline 23 is cooled and the condensate is precipitated, and then enters the secondary separator 24 to remove the condensate.

[0098] In the above specific embodiments, the purpose, technical solutions and beneficial effects of the present invention have been further described in detail. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An oil and gas gathering and processing system for a fire flooding oilfield, characterized in that, it includes: An oil and gas collection unit, having an oil gathering pipeline and a gas gathering pipeline connected to a Christmas tree, the oil gathering pipeline is connected to an oil gathering header, the gas gathering pipeline is connected to a gas gathering header and a water blending system, and a first communication pipeline is connected between the oil gathering pipeline and the gas gathering pipeline; An oil and gas processing unit, having a gas-liquid separator connected to the oil gathering header and a production separator connected to the gas gathering header, and a second communication pipeline is connected between the inlet of the gas-liquid separator and the inlet of the production separator.

2. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 1, characterized in that, The gas phase outlet of the gas-liquid separator and the gas phase outlet of the production separator are connected to a secondary separator through a gas phase pipeline.

3. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 2, characterized in that, A cooling device is provided on the gas phase pipeline, and the cooling device has a cooling water casing sleeved on the gas phase pipeline, and cooling water is passed through the cooling water casing.

4. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 1, characterized in that, The liquid phase outlet of the gas-liquid separator and the liquid phase outlet of the production separator are connected to a crude oil dehydration system through a liquid phase pipeline.

5. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 1 or 4, characterized in that, The discharge outlets of the gas-liquid separator and the production separator are connected to a venting device through a venting pipeline.

6. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 2, characterized in that, The liquid phase outlets of the gas-liquid separator, the production separator and the secondary separator are connected to a crude oil dehydration system through a liquid phase pipeline.

7. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 2 or 6, characterized in that, The discharge outlets of the gas-liquid separator, the production separator and the secondary separator are connected to a venting device through a venting pipeline.

8. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 2, characterized in that, The gas phase outlet of the secondary separator is connected to a gas processing system.

9. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 2, characterized in that, Safety valves are provided at the discharge outlets of the gas-liquid separator, the production separator and the secondary separator.

10. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 2, characterized in that, Gas phase self-operated regulating valves are provided at the gas phase outlets of the gas-liquid separator, the production separator and the secondary separator.

11. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 2, characterized in that, Liquid phase electric regulating valves are provided at the liquid phase outlets of the gas-liquid separator, the production separator and the secondary separator.

12. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 1, characterized in that, A pressure transmitter, a first temperature transmitter, a first check valve, and a sampling stop valve are provided on both the oil gathering pipeline and the gas gathering pipeline.

13. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 1, characterized in that, a second check valve and a first switch valve are provided on the first connecting pipeline.

14. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 1 or 13, characterized in that, a second switch valve is provided on the oil gathering pipeline, and the second switch valve is located on the oil gathering pipeline between the oil gathering header and the first connecting pipeline; a third switch valve is provided on the gas gathering pipeline, and the third switch valve is located on the gas gathering pipeline between the Christmas tree and the first connecting pipeline.

15. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 3, characterized in that, second temperature transmitters are respectively provided at both ends of the gas pipeline in the cooling device.

16. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 3, characterized in that, a cooling water channel surrounding the gas pipeline is formed in the cooling water casing, and the opposite ends of the cooling water channel are respectively connected with a cooling water inlet pipe and a cooling water outlet pipe.

17. The oil and gas gathering and processing system for a fire flooding oilfield according to claim 16, characterized in that, a third connecting pipeline is connected between the cooling water inlet pipe and the cooling water outlet pipe, and a fourth switch valve is provided on the third connecting pipeline.

18. An oil and gas gathering and processing process for a fire flooding oilfield, characterized in that, comprises: In the initial stage of fire flooding oilfield development, a part of the gas gathering pipeline connected to the Christmas tree is closed and used as a water injection pipeline, and water is injected into the oil gathering pipeline through the first connecting pipeline connected between the gas gathering pipeline and the oil gathering pipeline to increase the temperature of the wellhead; After the fire flooding becomes effective, the first connecting pipeline is cut off, and the gas gathering pipeline is opened for normal gas gathering operation.

19. The oil and gas gathering and processing process for a fire flooding oilfield according to claim 18, characterized in that, further comprises: When the production separator for processing the gas collected by the gas gathering pipeline needs to be overhauled, the gas is introduced into the gas-liquid separator for processing through the second connecting pipeline connected between the inlet of the production separator and the inlet of the gas-liquid separator; When the gas-liquid separator for processing the liquid collected by the oil gathering pipeline needs to be overhauled, the liquid is introduced into the production separator for processing through the second connecting pipeline.

20. The oil and gas gathering and processing process for a fire flooding oilfield according to claim 19, characterized in that, further comprises: A cooling device is arranged on the gas pipeline connected to the gas phase outlet of the production separator and the gas phase outlet of the gas-liquid separator, and a cooling water channel surrounding the gas pipeline and capable of cooling the gas in the gas pipeline is formed in the cooling device.

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