Oil-gas-water three-phase separation device and separation method for promoting gas desorption and defoaming

Abstract

The invention discloses an oil-gas-water three-phase separation device for promoting gas desorption and defoaming and a separation method, and belongs to the field of gathering and transportation of ground engineering. The pre-separator is separated from the main separator, so that the effect of improving the stability of a flow field in the main separator can be achieved. The disturbance paddle is mounted below the inner wall of the main separator, gas desorption of gas-dissolved crude oil can be accelerated through the rotary desorption-promoting disturbance paddle, the foaming process is promoted, and the separation efficiency is improved. The defoaming component is composed of the guide rail, the first scraper blade and the second scraper blade, the first scraper blade and the second scraper blade are installed on the guide rail, the two defoaming scraper blades move left and right in the direction of the top guide rail, and when the two defoaming scraper blades are attached together, the foam breaking task of foamed crude oil can be efficiently completed. By arranging a weir plate, a water outlet pipe, an oil outlet pipe and a second gas outlet pipe, oil-gas-water separation can be achieved after desorption and defoaming are completed. Therefore, the separation device is more efficient and simpler to separate the foaming fluid, and can solve the problems in the prior art.

Description

Technical Field

[0001] The present invention belongs to the field of CO2-EOR surface engineering gathering and transportation in the CCUS industry chain, and relates to an oil-gas-water three-phase separation device and a separation method for promoting gas desorption and defoaming. Background Art

[0002] Carbon dioxide capture, storage and enhanced oil recovery technology (CCS-EOR) is one of the main paths of carbon capture, utilization and storage (CCUS) technology. It can not only improve the recovery rate of crude oil, but also protect the environment and reduce the greenhouse effect. It has become a global research hotspot. Among them, CO2 flooding (CO2-EOR) is an important part of the CO2 injection development of oil fields. While improving the recovery rate, it also brings new problems to the surface engineering of oil fields. Part of the CO2 injected into the formation is effectively sealed in the formation, and the other part will enter the ground with the produced fluid (the CO2 content in the associated gas ranges from 5% to 90% at different production stages). Among them, the three-phase separation of oil, gas and water in the CO2 flooding produced fluid is an important part of the CO2-EOR surface engineering production process. Its separation efficiency directly affects the effects of subsequent oil and gas metering, oil and gas treatment and sewage treatment, as well as the material selection, selection and operating life of related equipment. Existing studies have shown that CO2-driven produced fluids have the characteristic of a high gas-liquid ratio. During the gathering and transportation process, as the pressure decreases, CO2 will be converted from a dissolved state to a gaseous state and desorbed from the produced fluid, causing the produced fluid to foam continuously. The bubbles in the CO2-driven produced fluid are mostly spherical and polyhedral foams, and the bubbles are very stable and can be maintained in an open container for more than ten hours. They form a stable foam layer that is not easily destroyed on the surface of the produced fluid. A large amount of foam occupies the gas phase space of the separator, thereby greatly reducing the three-phase separation efficiency.

[0003] Feng Chunbo studied the desorption characteristics of CO2 gas in crude oil in Heilongjiang 59 area of ​​Jilin Oilfield and found that when the separation temperature was 50℃ and the pressure dropped from 0.52MPa to 0.103MPa, the desorption percentage was 15% when the desorption time was 534s; when it reached 3516s, the desorption percentage was only 22.92%. According to the current specifications, the gas-liquid separation time of foaming crude oil cannot exceed 30min. Therefore, the CO2 desorption rate is very low by the method of reducing pressure alone, far exceeding the residence time required by the specification. Guo Xuhui studied the desorption characteristics of CO2 gas in Huang 3 block of Changqing Oilfield and found that when the separation temperature was 40℃ and the pressure dropped from 0.6MPa to 0.1MPa, the liquid phase residence time was 6min. By increasing the centrifugal inlet component and increasing the disturbance of the fluid, the CO2 desorption rate increased from 58.94% to 69.91%. If the residence time is further increased, the CO2 desorption rate will not change significantly. At present, the desorption of CO2 and the efficiency of gas-liquid separation are promoted by increasing the size of the separator or heating and continuously adding chemical agents for defoaming. Increasing the size of the separator leads to increased investment; heating increases operating energy consumption, and the formation water has a serious scaling tendency, which is easy to block pipelines and equipment, affecting the normal production of the oil field; chemical defoamers can effectively increase the defoaming rate, but they need to be added continuously, which increases the operating cost.

[0004] CN112755594A discloses a gas-liquid separator, wherein the cavity of the gas-liquid separator includes a cyclone bubble breaking device, a demister separation device, a defoaming paddle and a foam buffer chamber, and the cavity of the gas-liquid separator includes a gas outlet and a liquid outlet; the cyclone bubble breaking device includes an upper outlet and a lower outlet, and the cyclone bubble breaking device is used to separate a gas-liquid mixture into a gas mixture and a liquid mixture, the gas mixture escapes from the upper outlet, and the liquid mixture flows out from the lower outlet; the demister separation device is arranged at the top of the cavity, and is used to condense the liquid in the gas mixture; the defoaming paddle is used to eliminate the foam of the liquid mixture; the foam buffer chamber is used to store the liquid mixture above the predetermined liquid level height, and eliminate the foam of the liquid mixture by chemical means; the gas outlet is arranged at the top of the cavity; and the liquid outlet is arranged at the bottom of the cavity.

[0005] CN110747007A discloses a gas-liquid separation device for CO2-driven produced fluid, comprising: a main separation module, the main separation module comprises a shell, inside the shell are arranged from left to right in sequence a rectifying component, a rotating defoaming paddle, a conical defoaming plate, and a foam buffer chamber; the upper end of the foam buffer chamber is provided with a first air outlet pipe, the first air outlet pipe is connected to a mist catcher, the lower end of the foam chamber is connected to a liquid outlet pipe, an anti-vortex plate is provided between the conical foam plate and the foam buffer chamber, an oil outlet pipe is provided at the lower end of the anti-vortex plate, and the liquid outlet pipe is connected to the oil outlet pipe; the pre-separation module comprises a cylinder located on the left side of the shell, the side surface of the cylinder is connected to an inlet pipe, gas-containing crude oil enters the cylinder in a rotating state through the inlet pipe, the upper end of the cylinder is connected to a second air outlet pipe, a liquid baffle plate is provided at one end of the cylinder close to the second air outlet pipe, a rotation-stop component is provided at the lower end of the cylinder, and a liquid distribution component is provided at the lower end of the rotation-stop component.

[0006] At present, the desorption and defoaming of CO2-driven produced fluids mainly adopts mechanical methods combined with thermochemical methods, relying on natural pressure reduction and mechanical collision for desorption, and relying on mechanical collision and heating and adding drugs to promote defoaming. There is still room for improvement in the control of desorption and defoaming parameters and cost reduction. For example, the above-mentioned gas-liquid separation device adopts a mechanical defoaming method to treat foaming crude oil, that is, the produced fluid flows through the mechanical components in the separator to increase fluid collision and promote gas-liquid separation. At the same time, a rotary defoaming paddle is used to complete the defoaming. The shortcomings are that on the one hand, there is a lack of gas-promoting desorption device in the dissolved gas crude oil; on the other hand, the rotation speed of the rotary defoaming paddle has a great influence on the defoaming behavior. If the rotation speed is too low, the defoaming efficiency will be low, or even the defoaming cannot be completed. If the rotation speed is too high, it will cause the liquid level in the separator to fluctuate and affect the stability of the flow field in the separator. Summary of the invention

[0007] The purpose of the present invention is to solve the problem that the prior art cannot achieve gas desorption and low defoaming rate, and to provide an oil-gas-water three-phase separation device and separation method for promoting gas desorption and defoaming.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] The present invention provides an oil-gas-water three-phase separation device for promoting gas desorption and defoaming, comprising a hollow main separator, wherein the main separator comprises a rectifying component, a guide rail, a disturbance paddle and a weir plate;

[0010] The rectifying component is vertically installed at one end of the inner wall of the main separator to form a buffer chamber; the guide rail is horizontally installed above the inner wall of the main separator, the disturbance paddle is horizontally installed below the inner wall of the main separator, the weir plate is vertically installed at the other end of the inner wall of the main separator, and the first scraper and the second scraper are vertically installed at both ends of the guide rail; the main separator located above the weir plate is provided with a second air outlet pipe, the main separator located on one side of the weir plate is provided with a water outlet pipe, and the main separator located on the other side of the weir plate is provided with an oil outlet pipe.

[0011] Preferably, a baffle is installed in the main separator near the end of the rectifying member.

[0012] Preferably, a pre-separator is connected to the main separator;

[0013] The pre-separator comprises a tapered cylindrical cavity, an inlet pipe and a first air outlet pipe are connected to the upper part of the tapered cylindrical cavity, and the other end of the first air outlet pipe is connected to the upper part of the buffer chamber; a first liquid outlet pipe is connected to the lower part of the tapered cylindrical cavity, and the other end of the first liquid outlet pipe is connected to the lower part of the buffer;

[0014] A first valve is installed on the inlet pipe, and a first pressure gauge is installed on the first outlet pipe.

[0015] Preferably, a second pressure gauge and a second valve are installed above the main separator, and the second valve is a pressure relief valve.

[0016] Preferably, a third valve and a first vortex flowmeter are installed on the water outlet pipe;

[0017] A fourth valve and a second vortex flowmeter are installed on the oil outlet pipe;

[0018] A fifth valve and a third vortex flowmeter are installed on the second air outlet pipe.

[0019] Preferably, a mist collector is also installed on the second air outlet pipe.

[0020] Preferably, there are a plurality of disturbance paddles, which are arranged at equal intervals and heights.

[0021] Preferably, the rectifying member is a disc structure, which is composed of a plurality of bars, and the outer wall of the disc structure is connected to the inner wall of the main separator;

[0022] There are gaps between each bar.

[0023] Preferably, a thermometer is installed at the end of the main separator.

[0024] The present invention proposes an oil-gas-water three-phase separation method for promoting gas desorption and defoaming, comprising the following steps:

[0025] The gas and liquid after preliminary separation enter the buffer chamber of the main separator, and the liquid enters the defoaming area after being stabilized by the rectifying component;

[0026] Under the action of the disturbance paddle, the gas dissolved in the crude oil is rapidly desorbed and foamed. At the same time, the first scraper and the second scraper move relative and oppositely along the guide rail. The formed foam is broken under the squeezing of the first scraper and the second scraper to complete the defoaming.

[0027] The separated water flows out from the water outlet pipe, the oil flows out from the oil outlet pipe, and the gas flows out through the second gas outlet pipe, thus achieving the three-phase separation of oil, gas and water.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The present invention proposes an oil-gas-water three-phase separation device that promotes gas desorption and defoaming. The disturbance paddle is installed below the inner wall of the main separator. The rotating disturbance paddle that promotes desorption can accelerate the gas desorption of dissolved crude oil, promote the foaming process, and improve the separation efficiency. The defoaming component composed of a guide rail, a first scraper and a second scraper, the first scraper and the second cover plate are installed on the guide rail, and the two defoaming scrapers move left and right along the direction of the top guide rail. When the two defoaming scrapers are attached together, the "bubble breaking" task of the foamed crude oil can be efficiently completed. By setting a weir plate, a water outlet pipe, an oil outlet pipe and a second air outlet pipe, the separation of oil, gas and water can be achieved after desorption and defoaming are completed. Therefore, the separation device proposed by the present invention is more efficient and simpler for the separation and treatment of foaming fluids, and can solve the problems of the inability to achieve gas desorption and low defoaming rate in the prior art.

[0030] Furthermore, the gas and liquid after preliminary separation enter the main separator, the gas changes its flow direction through the baffle, and the liquid passes through the rectifying component to further reduce the unstable flow of the fluid after entering the main separator.

[0031] Furthermore, in the centrifugal cyclone pre-separator, the dissolved gas crude oil can be initially separated into gas and liquid under the action of centrifugal force, which can effectively reduce the influence of the fluid on the stability of the flow field in the main separator when the incoming liquid is unstable.

[0032] Furthermore, the second air outlet pipe of the main separator contains a baffled mist collector, which can effectively reduce liquid carried in the gas.

[0033] Furthermore, a pressure relief valve is provided on the top of the main separator housing to prevent excessive pressure in the main separator and play a protective role. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 This is a structural diagram of the oil-gas-water three-phase separation device for promoting gas desorption and defoaming of the present invention.

[0036] Figure 2 This is a three-dimensional structural diagram of the oil-gas-water three-phase separation device for promoting gas desorption and defoaming of the present invention.

[0037] Figure 3 It is a top view of the inlet pipe tangently connected to the tapered cylindrical cavity of the present invention.

[0038] Figure 4 This is a flow chart of the oil-gas-water three-phase separation method for promoting gas desorption and defoaming of the present invention.

[0039] Among them: 1-inlet pipe; 2-first air outlet pipe; 3-first liquid outlet pipe; 4-tapered cylindrical cavity; 5-buffer chamber; 6-baffle; 7-rectifying component; 8-guide rail; 9-first scraper; 10-second scraper; 11-mist collector; 12-fifth valve; 13-third turbine flowmeter; 14-disturbance paddle; 15-water outlet pipe; 16 third valve; 17-first turbine flowmeter; 18-oil outlet pipe; 19-fourth valve; 20-second turbine flowmeter; 21-second air outlet pipe; 22-second pressure gauge; 23-thermometer; 24-second valve; 25-first pressure gauge; 26-first valve; 27-main separator; 28-weir plate. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0043] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does 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 cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0044] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0045] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" 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 or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0047] See also Figure 1 to Figure 2 , which is a structural diagram of an oil-gas-water three-phase separation device for promoting gas desorption and defoaming proposed by the present invention. The device includes a centrifugal rotating pre-separator and a main separator 27.

[0048] The main separator 27 includes a baffle 6 , a rectifying plate 7 , a rotary desorption-promoting disturbance paddle 14 , a guide rail 8 , a first scraper 9 , a second scraper 10 , a weir plate 28 , a water outlet pipe 15 , an oil outlet pipe 18 and a second gas outlet pipe 21 .

[0049] The rectifying member 7 is vertically mounted at one end of the inner wall of the main separator 27 to form a buffer chamber 5; the guide rail 8 is horizontally mounted above the inner wall of the main separator 27, the disturbance paddle 14 is horizontally mounted below the inner wall of the main separator 27, the weir plate 28 is vertically mounted at the other end of the inner wall of the main separator 27, and the first scraper 9 and the second scraper 10 are vertically mounted at both ends of the guide rail 8; the main separator 27 located above the weir plate 28 is provided with a second gas outlet pipe 21, the main separator 27 located on one side of the weir plate 28 is provided with a water outlet pipe 15, and the main separator 27 located on the other side of the weir plate 28 is provided with an oil outlet pipe 18. The disturbance paddle 14 is mounted below the inner wall of the main separator 27, and there are a plurality of disturbance paddles 14, which are arranged at equal intervals and heights. The rotating desorption-promoting disturbance paddle 14 can accelerate the gas desorption of dissolved crude oil, promote the foaming process, and improve the separation efficiency. The defoaming component is composed of a guide rail 8, a first scraper 9 and a second scraper 10. The first scraper 9 and the second cover plate 10 are installed on the guide rail 8. The two defoaming scrapers move left and right along the top guide rail 8. When the two defoaming scrapers are attached together, the "bubble breaking" task of the foamed crude oil can be completed efficiently. By setting the weir plate 28, the water outlet pipe 15, the oil outlet pipe 18 and the second gas outlet pipe 21, the separation of oil, gas and water can be achieved after the desorption and defoaming are completed. Therefore, the separation device proposed by the present invention is more efficient and simpler for the separation and treatment of the foaming fluid, and can solve the problem that the gas desorption and the low defoaming rate cannot be achieved in the prior art.

[0050] The rectifying component 7 is a disc structure, which is composed of a number of bars. The outer wall of the disc structure is connected to the inner wall of the main separator 27; there is a gap between each bar. A baffle 6 is installed near the end of the rectifying component 7 in the main separator 28. The gas and liquid after preliminary separation enter the main separator 27. The gas changes its flow direction through the baffle 6, and the liquid further reduces the unstable flow of the fluid after entering the main separator 27 through the rectifying component. The third valve 16 and the first vortex flowmeter 17 are installed on the water outlet pipe 15; the fourth valve 19 and the second vortex flowmeter 20 are installed on the oil outlet pipe 18; the fifth valve 12 and the third vortex flowmeter 13 are installed on the second outlet pipe 21. A mist collector 11 is also installed on the second outlet pipe 21, which can effectively reduce the liquid carried in the gas. A second pressure gauge 22 and a second valve 24 are installed above the main separator 28. The second valve 24 is a pressure relief valve. The installation of the pressure relief valve can avoid excessive pressure in the main separator and play a protective role. A thermometer 23 is installed at the end of the main separator 27, and displays the temperature of the gas phase fluid through an insertion thermometer.

[0051] The centrifugal rotating pre-separator comprises a rectangular cross-section inlet pipe 1 , a tapered cylindrical cavity 4 , a first air outlet pipe 2 , a first liquid outlet pipe 3 , and a first pressure gauge 25 .

[0052] The pre-separator is connected to the main separator 27, and includes a tapered cylindrical cavity 4, an inlet pipe 1 and a first gas outlet pipe 2 are connected to the top of the tapered cylindrical cavity 4, and the other end of the first gas outlet pipe 2 is connected to the top of the buffer chamber 5; a first liquid outlet pipe 3 is connected to the bottom of the tapered cylindrical cavity 4, and the other end of the first liquid outlet pipe 3 is connected to the bottom of the buffer 5; a first valve 26 is installed on the inlet pipe 1, and a first pressure gauge 25 is installed on the first gas outlet pipe 2. The gas-containing crude oil enters the tapered cylindrical cavity 4 in a rotating state through the inlet pipe 1, the first gas outlet pipe 2 is connected to the top of the main separator 27, and the first liquid outlet pipe 3 is connected to the bottom of the main separator 27.

[0053] The gas and liquid separated initially by the pre-separator enter the main separator 27. The gas changes its flow direction through the baffle 6 to avoid direct impact on the liquid surface. The liquid enters the defoaming chamber after being stabilized by the rectifying plate 7. Under the action of the rotating desorption-promoting disturbance paddle 14 at the bottom of the main separator housing 27, the gas dissolved in the crude oil is rapidly desorbed and foamed. At the same time, the first and second scrapers 9 and 10 of the translational defoaming move relative and oppositely along the guide rail 8. The formed foam is broken under the pressure of the first and second scrapers 9 and 10 of the translational defoaming in the defoaming chamber to complete the defoaming. The separated water flows out from the water outlet pipe 15, the oil flows out from the oil outlet pipe 18, and the gas flows out from the second gas outlet pipe 21 after the last separation through the baffled mist collector 11.

[0054] The following is a detailed description of an oil-gas-water three-phase separation device for promoting gas desorption and defoaming proposed by the present invention:

[0055] 1. Components, position connection relationship and working principle of the pre-separator

[0056] The pre-separator includes a first valve 26, an inlet pipe 1, a tapered cylindrical cavity 4, a first liquid outlet pipe 3, a first air outlet pipe 2 and a pressure gauge 25; wherein the tapered cylindrical cavity 4 is the main structure, connecting other pre-separator components (carrying other pre-separator components); the incoming fluid enters the upper part of the tapered cylindrical cavity 4 through the first valve 26 in an open state, and the free liquid of the heavy component is thrown out by the tangential cyclone action, and the free liquid slides into the lower cavity along the upper cavity wall of the tapered cylindrical cavity 4, and enters the main separator 27 through the first liquid outlet pipe 3, and the light component gas removed from the free liquid flows into the first air outlet pipe 2 through the sleeve at the upper part of the tapered cylindrical cavity 4 and enters the main separator 27; the tapered cylindrical cavity 4 has a certain volume and generates super gravity through cyclone, which can play a role of preliminary buffering and pre-separation.

[0057] 1) The first valve 26 is installed on the inlet pipe 1, and the flow cross-section of the first valve 26 in the fully open state coincides with the flow cross-section of 1 (the vertical center lines of the flow cross-sections of the two coincide); the first valve 26 divides the inlet pipe 1 into front and rear pipe sections, and connects the front and rear pipe sections. The opening and closing state of its valve core can open or close the fluid entering the device of the present invention, and the opening of its valve core from 0% to 100% can control the flow rate of the incoming fluid.

[0058] 2) The tapered cylindrical cavity 4 is a hollow structure, the upper part of which is a cylinder, and the cylinder has a sleeve structure connected to the top of the cylinder (the sleeve is a pipe section with a hollow structure, the upper opening of which is at the top of the cylinder and the lower opening is inside the cylinder), and the sleeve extends downward from the top but does not exceed the end line of the bottom surface of the cylinder; the lower part of the tapered cylindrical cavity 4 is a tapered cone that is wide at the top and narrow at the bottom, and the top of the cone is connected to the bottom of the cylinder, and the connection between the two is the same inner and outer circular cross-section, the bottom of the cone does not reach the tip of the cone, and its bottom cross-sectional area is larger than the cross-sectional area of ​​the first liquid outlet pipe 3, and there is an opening on the center line of the bottom, and the area of ​​the opening is the same as the inner diameter cross-sectional area of ​​the first liquid outlet pipe 3.

[0059] 3) The inlet pipe 1 is installed at the top of the upper cylinder of the tapered cylindrical cavity 4, and the inlet pipe 1 is tangentially connected to the tapered cylindrical cavity 4. Figure 3 The tangential connection allows the incoming fluid to be restricted by the cylindrical cavity to perform swirl motion, thereby creating a rotational centrifugal force (>G) that exceeds gravity (G), which is beneficial for separating the macromolecular components from the fluid, presenting a gas-liquid separation state at a macroscopic level.

[0060] 4) The first liquid outlet pipe 3 is installed at the bottom of the tapered cylindrical cavity 4, and its front end is connected to the cone bottom of the tapered cylindrical cavity 4. The flow centerline of the first liquid outlet pipe 3 coincides with the perpendicular line of the cross section of the cone bottom of the tapered cylindrical cavity 4. The inner diameter cross-sectional area of ​​the first liquid outlet pipe 3 is described in 2); the rear end of the first liquid outlet pipe 3 is connected to the lower part of the buffer chamber 5 of the main separator 27.

[0061] 5) The first air outlet pipe 2 is installed at the top of the tapered cylindrical cavity 4, and its front end is connected to the upward opening of the sleeve structure at the top end of the upper cylindrical body of the tapered cylindrical cavity 4. The flow centerline of the first air outlet pipe 2 coincides with that of the sleeve, and the inner diameter cross-sectional area of ​​the two is the same; the rear end of the first air outlet pipe 2 is connected to the upper part of the buffer chamber 5 of the main separator 27.

[0062] 6) The pressure gauge 25 is installed on the horizontal pipe section of the first air outlet pipe 2, and is a three-way pressure-drawing connection. It can display the fluid pressure in the first air outlet pipe 2 on-site and reflect the pressure in 4 according to the principle of communicating vessels.

[0063] 2. Components, position connection relationship and working principle of the main separator 27

[0064] The main separator 27 is a horizontal cylindrical hollow tank as a whole, which carries various components of the main separator, including a buffer chamber 5, a baffle 6, a rectifying member 7, a guide rail 8, a first scraper 9, a second scraper 10, a mist collector 11, a fifth valve 12, a third turbine flowmeter 13, a rotary desorption disturbance paddle 14, a water outlet pipe 15, a third valve 16, a first turbine flowmeter 17, an oil outlet pipe 18, a fourth valve 19, a second turbine flowmeter 20, a second air outlet pipe 21, a second pressure gauge 22, a thermometer 23, a second valve (pressure relief valve) 24, a first pressure gauge 25, and a weir plate 28. ; Among them, the incoming liquid from the first liquid outlet pipe 3 enters the bottom of the buffer chamber 5 for further buffering. The buffering process can further desorb CO2. The incoming gas from the first gas outlet pipe 2 enters the top of the buffer chamber 5. The airflow impacts the baffle 6 to break the carried droplets and release the CO2. The airflow after impact merges with the incoming liquid in the buffer chamber 5 and flows to the middle cavity of the main separator. It first passes through the rectifying component 7 to reduce the fluid disturbance caused by the impact, and then enters the middle cavity of the main separator 27. The flow rate is controlled so that the liquid level in the middle cavity reaches the middle of the cavity (i.e., half the liquid level). The rotation of the bottom of the middle cavity The desorption-promoting disturbance paddle 14 controls the stirring of the liquid phase, and the rotating shear force of the disturbance paddle again shears and breaks the foam in the liquid phase. The broken foam releases CO2 and floats upward into the gas phase space. The liquid phase fluid at the horizontal middle half liquid level of the middle cavity is squeezed by the first scraper 9 and the second scraper 10 that move back and forth in the horizontal direction, further crushing the foam in the liquid phase. The liquid phase fluid passing through the middle cavity is gradually stratified after defoaming, and the water in the water layer at the bottom of the liquid phase is discharged through the outlet pipe 15. The opening and closing of the third valve 16 is controlled on the way, and the first turbine flowmeter 17 is used to control the flow of the liquid phase. The discharge volume is measured, and the oil layer above the liquid water layer goes over the weir plate 28 and enters the rear cavity of the main separator 27, and is discharged through the oil outlet pipe 18. The opening and closing is controlled by the fourth valve 19 on the way, and the discharge volume is measured by the second turbine flowmeter 20. The gas phase in the main separator 27 can be discharged by the second valve (pressure relief valve) 24 when necessary, and is discharged through the second gas outlet pipe 21 during normal production. The droplets carried in the gas phase are first condensed and captured by the mist collector 11 and fall back into the main separator, and then the opening and closing are controlled by the fifth valve 12, and the exhaust volume is measured by the third turbine flowmeter 13.

[0065] 1) The buffer chamber 5 is located at the starting end of the fluid flow of the main separator 27.

[0066] 2) The baffle 6 is located in the gas phase space of the buffer chamber 5 and is a rectangular steel plate. One long side of the steel plate is connected to the inner wall of the starting end of the main separator, and the other long side of the steel plate is inclined downward (inclination angle 15° to 45°).

[0067] 3) The rectifying component 7 is used to separate the buffer chamber 5 from the middle section of the main separator 27 . The rectifying component 7 is a circular plate with a horizontal grid structure and is connected to the inner wall of the main separator 27 on all sides.

[0068] 4) Both ends of the guide rail 8 are suspended at the top of the middle section of the main separator 27 by steel short circuits. The guide rail 8 has a sliding groove in the longitudinal direction for hanging the first scraper 9 and the second scraper 10.

[0069] 5) The first scraper 9 and the second scraper 10 are suspended in the sliding groove of the guide rail 8, and their working surfaces are trapezoidal plates with arc-shaped left and right sides so that they can fit against the inner wall of the main separator (leaving a gap to facilitate scraping). In addition, the scrapers are pulled horizontally by a driving device, and the driving device is controlled by an automatic control system (the driving device and the control system only need to realize their functions and are not within the scope of protection of the present invention).

[0070] 6) The second pressure gauge 22 is located on the outer wall of the middle part of the main separator 27, and the second pressure gauge 22 is connected to the gas phase space of the main separator 27 through a vertical pressure-leading pipe.

[0071] 7) The second valve (pressure relief valve) 24 is located on the outer wall of the middle part of the main separator 27 and is connected to the gas phase space of the main separator 27 through a vertical pipe section. When an abnormal operating condition occurs or pressure relief is required, this valve can be opened to play a role in pressure safety control.

[0072] 8) The second air outlet pipe 21 is located on the outer wall of the main separator above the weir plate 28 at the rear section of the main separator 27. It is an "L"-shaped pipe section, on which facilities such as a mist collector 11, a fifth valve 12, and a third turbine flowmeter 13 are installed in sequence.

[0073] 9) The mist collector 11 is located on the vertical pipe at the starting point of the second air outlet pipe 21. It is a multi-layer wire mesh superposition structure and is cylindrical in shape as a whole. It is used to condense liquid particles carried in the exhaust air flow.

[0074] 10) The fifth valve 12 is located on the horizontal pipe section of the second air outlet pipe 21 , after the mist collector 11 .

[0075] 11) The third turbine flowmeter 13 is located on the horizontal pipe section of the second outlet pipe 21 , after the fifth valve 12 .

[0076] 12) The thermometer 23 is located on the outer wall of the gas phase space at the end of the main separator 27, and displays the gas phase fluid temperature through an inserted thermometer.

[0077] 13) The rotary desorption-promoting disturbance paddle 14 is located at the bottom of the middle section of the main separator 27, and consists of several disturbance paddles evenly distributed at the bottom of the main separator (the number depends on the size and length of the separator, and the figure shows that the number is 3). In addition, the disturbance paddle 14 is rotated by the traction of a driving device, and the driving device is controlled by an automatic control system (the driving device and the control system only need to realize their functions and are not within the scope of protection of the present invention).

[0078] 14) The outlet pipe 15 is located at the bottom of the separator in front of the weir plate 28 at the end of the middle section of the main separator 27. It is an "L"-shaped pipe section, and is equipped with the third valve 16, the first turbine flowmeter 17 and other facilities in sequence.

[0079] 15) The third valve 16 is located on the horizontal pipe section of the outlet pipe 15 and is used to control the opening and water volume of the drainage.

[0080] 16) The first turbine flowmeter 17 is located on the horizontal pipe section of the water outlet pipe 15, after the third valve 16.

[0081] 17) The weir plate 28 separates the oil-water mixing chamber in the middle section of the main separator 27 from the oil chamber in the end section of the main separator 27. The weir plate 28 is a semicircular steel plate, and the arc is connected to the inner wall of the main separator 27 (without a gap).

[0082] 18) The oil outlet pipe 18 is located at the bottom of the oil chamber at the end of the main separator 27. It is an "L"-shaped pipe section, and is sequentially installed with the fourth valve 19, the second turbine flowmeter 20 and other facilities.

[0083] 19) The fourth valve 19 is located on the horizontal pipe section of the oil outlet pipe 18 and is used to control the opening and oil volume of the oil discharge.

[0084] 20) The second turbine flowmeter 20 is located on the horizontal pipe section of the oil outlet pipe 18, after the fourth valve 19.

[0085] The present invention proposes an oil-gas-water three-phase separation method for promoting gas desorption and defoaming, such as Figure 4 As shown, the following steps are included:

[0086] Step 1: The gas and liquid after preliminary separation enter the buffer chamber 5 of the main separator 27, and the liquid enters the defoaming area after being stabilized by the rectifying component 7;

[0087] Step 2: Under the action of the disturbance paddle 14, the gas dissolved in the crude oil is rapidly desorbed and foamed, and at the same time, the first scraper 9 and the second scraper 10 make relative and opposite translation along the guide rail 8, and the formed foam is broken under the extrusion of the first scraper 9 and the second scraper 10 to complete the defoaming;

[0088] Step 3: The separated water flows out from the water outlet pipe 15, the oil flows out from the oil outlet pipe 18, and the gas flows out through the second gas outlet pipe 21, thereby achieving three-phase separation of oil, gas and water.

[0089] Specific examples are as follows:

[0090] The equilibrium pressure of the dissolved gas PVT instrument is 0.6 MPa, the pressure in the separator is 0.1 MPa, the pressure difference is 0.5 MPa, and the temperature is 30°C. The relationship between the desorption rate of CO2 in crude oil and the residence time is shown in Table 1.

[0091] Table 1. CO2 desorption rate in crude oil changes with residence time

[0092]

[0093] The maximum diameter of the oil droplets in the separated carbon dioxide gas is 58.1μm and the minimum is 30.7μm, meeting the requirement of less than 100um.

[0094] The present invention proposes an oil-gas-water three-phase separation device that promotes gas desorption and defoaming. The inlet pipe of the cyclone separation module is connected to the tapered cylindrical cavity at an angle and tangentially. The tangential inlet has the function of rotating the fluid entering the cavity to generate a rotating flow field. The gas phase moves toward the axis of the pre-separation cavity, and rises to the first gas outlet pipe at the top to be discharged. The liquid phase moves toward the cavity wall, and forms a downward external vortex under the action of centrifugal force and gravity, and flows into the main separation module from the first liquid outlet pipe at the bottom of the cavity. Therefore, the technical effect of achieving preliminary effective separation of gas and liquid in the pre-separation module through rotating centrifugal force and rotating disturbance is achieved, and the kinetic energy of the fluid after the preliminary separation is effectively utilized and reduced, and the stability of the flow field in the main separator is not directly affected. The gas and liquid after preliminary separation enter the main separator module, the gas changes its flow direction through the baffle, and the liquid further reduces the unstable flow of the fluid after entering the main separation module through the rectifying component. The gas desorption of dissolved gas crude oil is accelerated by the rotating desorption-promoting disturbance paddle, the foaming process is promoted, and the separation efficiency is improved. On the other hand, the translational defoaming scraper moves left and right along the direction of the top guide rail to complete the task of "breaking bubbles" of the foamed crude oil. The second outlet pipe of the separator contains a baffled mist collector, which further effectively reduces the liquid carried in the gas. A pressure relief valve is provided on the top of the separator shell to avoid excessive pressure in the separator, play a protective role, and thus achieve effective separation of gas-containing crude oil, gas and water. This patent has the technical effect of sufficient separation of gas-containing crude oil. Therefore, the present invention changes the liquid inlet method of the separator inlet, adds a desorption disturbance device for dissolved gas crude oil, and designs a new defoaming structure to form a more efficient and simple oil-gas-water three-phase separation and defoaming device for the separation and treatment of foaming fluids. It is mainly used in the oil-gas-water separation link of CO2-driven produced fluids, and can achieve efficient desorption, defoaming and separation of CO2-driven produced fluids.

[0095] It has the following advantages:

[0096] 1) The centrifugal cyclone pre-separator of the present invention is separated from the main separator, which can increase the stability of the flow field in the main separator;

[0097] 2) The present invention also includes a rotary desorption-promoting disturbance impeller, which is installed at the bottom of the defoaming chamber in the main separator module, so as to promote the desorption of dissolved gas in the crude oil; so that the dissolved gas in the crude oil is accelerated to escape from the liquid phase system under disturbance;

[0098] 3) A defoaming component is designed, including a guide rail and a translational defoaming scraper. The guide rail is installed on the top of the defoaming chamber, and the translational defoaming scraper is installed in the middle of the defoaming chamber. The defoaming scrapers move towards and in the opposite direction. When the scrapers are attached together, the foam is broken, which has the function of "breaking foam";

[0099] 4) In the centrifugal cyclone pre-separator, the dissolved gas crude oil can be initially separated into gas and liquid under the action of centrifugal force. This module can effectively reduce the impact of the fluid on the stability of the flow field in the main separator when the incoming liquid is unstable;

[0100] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, 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-gas-water three-phase separation device for promoting gas desorption and defoaming, characterized in that: The invention comprises a hollow main separator (27), wherein the main separator (27) comprises a fairing member (7), a guide rail (8), a disturbance paddle (14) and a weir plate (28); The rectifying component (7) is vertically mounted on one end of the inner wall of the main separator (27) to form a buffer chamber (5); the guide rail (8) is horizontally mounted above the inner wall of the main separator (27); the disturbance paddle (14) is horizontally mounted below the inner wall of the main separator (27); the weir plate (28) is vertically mounted on the other end of the inner wall of the main separator (27); a first scraper (9) and a second scraper (10) are vertically mounted on both ends of the guide rail (8); a second air outlet pipe (21) is provided on the main separator (27) located above the weir plate (28); a water outlet pipe (15) is provided on the main separator (27) located on one side of the weir plate (28); and an oil outlet pipe (18) is provided on the main separator (27) located on the other side of the weir plate (28).

2. The oil-gas-water three-phase separation device for promoting gas desorption and defoaming according to claim 1 is characterized in that: A baffle (6) is installed in the main separator (28) near the end of the rectifying member (7).

3. The oil-gas-water three-phase separation device for promoting gas desorption and defoaming according to claim 1 is characterized in that: A pre-separator is connected to the main separator (27); The pre-separator comprises a tapered cylindrical cavity (4), an inlet pipe (1) and a first air outlet pipe (2) are connected above the tapered cylindrical cavity (4), the other end of the first air outlet pipe (2) is connected to the top of the buffer chamber (5); a first liquid outlet pipe (3) is connected below the tapered cylindrical cavity (4), the other end of the first liquid outlet pipe (3) is connected to the bottom of the buffer (5); A first valve (26) is installed on the inlet pipe (1), and a first pressure gauge (25) is installed on the first outlet pipe (2).

4. The oil-gas-water three-phase separation device for promoting gas desorption and defoaming according to claim 1, characterized in that: A second pressure gauge (22) and a second valve (24) are installed above the main separator (28), and the second valve (24) is a pressure relief valve.

5. The oil-gas-water three-phase separation device for promoting gas desorption and defoaming according to claim 1, characterized in that: A third valve (16) and a first vortex flowmeter (17) are installed on the water outlet pipe (15); A fourth valve (19) and a second vortex flowmeter (20) are installed on the oil outlet pipe (18); A fifth valve (12) and a third vortex flowmeter (13) are installed on the second air outlet pipe (21).

6. The oil-gas-water three-phase separation device for promoting gas desorption and defoaming according to claim 5, characterized in that: A mist collector (11) is also installed on the second air outlet pipe (21).

7. The oil-gas-water three-phase separation device for promoting gas desorption and defoaming according to claim 1, characterized in that: There are a plurality of disturbance paddles (14), which are arranged at equal intervals and heights.

8. The oil-gas-water three-phase separation device for promoting gas desorption and defoaming according to claim 1, characterized in that: The rectifying component (7) is a disc structure composed of a plurality of bars, and the outer wall of the disc structure is connected to the inner wall of the main separator (27); There are gaps between each bar.

9. The oil-gas-water three-phase separation device for promoting gas desorption and defoaming according to claim 1, characterized in that: A thermometer (23) is installed at the end of the main separator (27).

10. A method for oil-gas-water three-phase separation by promoting gas desorption and defoaming, characterized in that: The steps include: The gas and liquid after preliminary separation enter the buffer chamber (5) of the main separator (27), and the liquid enters the defoaming area after being stabilized by the rectifying component (7); Under the action of the disturbance paddle (14), the gas dissolved in the crude oil is rapidly desorbed and foamed, and at the same time, the first scraper (9) and the second scraper (10) move relative and opposite directions along the guide rail (8), and the formed foam is broken under the pressure of the first scraper (9) and the second scraper (10), and the foam is defoamed; The separated water flows out from the water outlet pipe (15), the oil flows out from the oil outlet pipe (18), and the gas flows out through the second gas outlet pipe (21), thereby achieving three-phase separation of oil, gas and water.

Images