Cascade rotational flow pre-water-diversion equipment

Abstract

The invention provides cascade rotational flow water pre-separation equipment, relates to the technical field of oil and gas gathering and transportation, and aims to solve the problem that separation of liquid drops with relatively wide particle size distribution cannot be realized by a rotational flow water pre-separation device in the prior art by adopting single rotation intensity. The equipment comprises a main rotational flow cavity and a plurality of auxiliary rotational flow cavities, wherein the main rotational flow cavity and a conical annular rotational flow increasing cavity form a centrifugal vertical field with 200-400 times of gravitational acceleration through static guide vanes; the auxiliary rotational flow cavity forms a centrifugal force field with 4000-6000 times of gravitational acceleration through the cylindrical cavity and the conical stable rotation cavity; the main rotational flow cavity and the auxiliary rotational flow cavity separate large-particle-size liquid drops and small-particle-size liquid drops respectively, and effective utilization of fluid energy is achieved. The mining cost of an onshore oil field can be saved, continuous production of the oil field is guaranteed, and economic benefits in the middle and later periods of oil field development are improved.

Description

TECHNICAL FIELD

[0002] The present application relates to the oil and gas gathering and processing technical field, and particularly relates to a step-by-step reinforced cyclone pre-water separation device. BACKGROUND

[0004] In the oil and gas gathering and processing field, with the continuous expansion of the oilfield production scale and long-term water injection development, at present, many domestic and foreign land and offshore oilfields have entered the high or super high water cut production period. The produced liquid of the land oilfield in China usually needs to be transported to a joint station for heating and dewatering treatment. After entering the high water cut stage, most of the heating energy is consumed in the heating and temperature rising of the water phase, which causes great energy waste. In order to solve the above problems, a pre-water separation device is usually arranged before a three-phase separator to separate water from the produced liquid. However, the conventional single-stage cyclone separation device has single cyclone intensity and basically fixed separation capacity and working condition range.

[0005] The applicant proposes an axial inlet static hydrocyclone for pre-dewatering of oil well produced liquid in patent CN104785384A. When the water content of the produced liquid is 70-90%, 50% of the water can be separated under the condition that the oil concentration of the separated water is less than 1500 mg / L. However, the present applicant finds that the prior art at least has the following technical problems:

[0006] The separation intensity and separation efficiency of the cyclone separation technology are closely related to the cyclone intensity of the flow field. The oil-water ratio of the produced liquid is relatively large and the particle size distribution of the dispersed oil droplets is very wide. The existing pre-water separation device uses single cyclone intensity for oil-water separation. It is difficult to further improve the water separation rate under the condition of ensuring the water quality, but the water content of the produced liquid is still as high as 70% or more after 50% of the water is separated, and there is still a large energy saving space. SUMMARY

[0008] Therefore, the purpose of the present application is to provide a step-by-step reinforced cyclone pre-water separation assembly to solve the technical problem that the hydrocyclone cannot simultaneously consider the wide particle size distribution range of the oil droplets under a large oil-water ratio in the prior art.

[0009] In order to achieve the above purpose, the present application provides a step-by-step cyclone pre-water separation device, which comprises a liquid inlet pipe, a flow guide, a flow guide blade, a spin increasing cavity, a main cyclone cavity, a flow stabilizing cone, a connecting pipe, a spin starting cavity, a spin stabilizing cavity, a secondary cyclone cavity, an oil guide pipe, an oil collecting chamber, a water collecting chamber, an oil discharge pipe and a water discharge pipe.

[0010] The liquid inlet pipe is a cylindrical pipe which can be connected with an upstream pipe through threads, quick connectors or welding.

[0011] The flow guide is a hemispherical-cylindrical-conical structure, which is placed in the liquid inlet pipe and the spin-increasing cavity; the flow guide blades are arranged on the flow guide; the flow guide blades can be in circular arc type, airfoil type or inclined plate type;

[0012] The spin-increasing cavity is a conical annular chamber located downstream of the liquid inlet pipe; the flow guide blades and the spin-increasing cavity are used in cooperation to generate a rotational flow with a centrifugal acceleration of 200-400 times of the gravitational acceleration;

[0013] The main rotational flow cavity is a cylindrical chamber located downstream of the spin-increasing cavity, which mainly separates a large amount of dispersed oil droplets with a size of more than 40 μm;

[0014] The flow stabilizing cone is located at the lower part of the main rotational flow cavity and is sealingly connected with the lower port of the main rotational flow cavity;

[0015] The oil guide pipe passes through the center of the flow stabilizing cone and connects the main rotational flow cavity and the oil collecting chamber;

[0016] The spin-starting cavity, the flow stabilizing cavity and the auxiliary rotational flow cavity are sequentially connected to form a cylindrical-conical-conical chamber structure; 3-5 chamber structures are uniformly inverted around the main rotational flow cavity;

[0017] The two ends of the connecting pipe are tangential to the wall surfaces of the main rotational flow cavity and the spin-starting cavity, and connect the main rotational flow cavity and the spin-starting cavity; the oil collecting pipe is arranged in the center of the spin-starting cavity and connects the spin-starting cavity and the oil collecting chamber;

[0018] The connecting pipe is used in cooperation with the spin-starting cavity and the flow stabilizing cavity to generate a rotational flow with a centrifugal acceleration of 4000-6000 times of the gravitational acceleration; the auxiliary rotational flow cavity mainly separates a small amount of dispersed oil droplets with a size of less than 40 μm, and the separated oil droplets enter the oil collecting chamber through the oil collecting pipe;

[0019] The main rotational flow cavity, the spin-starting cavity, the flow stabilizing cavity and the auxiliary rotational flow cavity are all located in the water collecting chamber; the lower end of the water collecting chamber is provided with the water outlet pipe;

[0020] The oil collecting chamber is located at the upper part of the water collecting chamber and is provided with a partition plate in the middle; the upper end of the water collecting chamber is provided with the oil outlet pipe.

[0021] As can be seen from the technical scheme provided by the application, the stepped rotational flow assembly provided by the embodiments of the application more reasonably and efficiently utilizes the rotational flow field to perform targeted separation of liquid droplets, can improve the pre-separation water efficiency, saves the exploitation cost of the high water cut oil field, and improves the economic benefit in the middle and late stages of oil field development. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1The structural schematic diagram of the stepped cyclone assembly provided by the embodiment of the present application.

[0024] Figure 2 The schematic diagram of the connection mode of a primary cyclone cavity and a secondary cyclone cavity in the embodiment of the present application.

[0025] The various marks in the drawings are as follows:

[0026] 1 - liquid inlet pipe; 2 - flow guide; 3 - flow guide vane; 4 - spin-increasing cavity; 5 - primary cyclone cavity; 6 - secondary cyclone cavity; 7 - cyclone stabilizing cavity; 8 - cyclone starting cavity; 9 - partition plate; 10 - oil guide pipe; 11 - oil collection chamber; 12 - oil discharge pipe; 13 - flow stabilizing cone; 14 - connecting pipe; 15 - water collection chamber; 16 - water discharge pipe. DETAILED DESCRIPTION

[0028] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described in detail below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0029] In the description of the present application, it should be noted that, unless otherwise specified, the meaning of "a plurality of" is two or more; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0030] In the description of the present application, it should also be noted that, unless otherwise specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0031] The existing pre-water separation device adopts a single cyclone intensity for oil-water separation, and the water content of the produced fluid after water separation of 50% is still as high as 70% or more, so there is still a large energy saving space. Therefore, the hydraulic cyclone of the previous single cyclone intensity is improved, and a step-by-step intensified cyclone device is proposed, which can control the cyclone intensity of different cyclone chambers to separate different particle size dispersed droplets, so as to realize targeted separation according to particle size, improve the utilization efficiency of fluid energy and improve the separation effect.

[0032] Specifically, referring to Figure 1 and Figure 2 , the present application provides a step-by-step cyclone assembly, which comprises a liquid inlet pipe 1, a main cyclone chamber 5, a secondary cyclone chamber 6, an oil collection chamber 11, a water collection chamber 6, an oil outlet pipe 12, a water outlet pipe 16 and a cyclone control element.

[0033] Among them, the cyclone control element respectively adopts guide vane 3 and rotating cavity 8 according to different cyclone intensity requirements.

[0034] The oil collection chamber and the water collection chamber are upper and lower connected tanks, which can be connected by flange and welding, and a partition plate 9 is arranged between the two chambers.

[0035] The main cyclone chamber 5 and the secondary cyclone chamber 6 are both located in the water collection chamber 15.

[0036] As shown in Figure 1 , the liquid enters the annular flow channel formed by the guide member 2 and the liquid inlet pipe 1 from the liquid inlet pipe 1, the guide vane 3 makes the oil-water mixture produce a circumferential motion speed, forming a rotating flow, and further the oil-water two-phase passes through the spin-increasing cavity 4, the rotation speed of the fluid is further increased due to the decrease of the rotation radius, the centrifugal acceleration reaches 200-400 times the gravity acceleration into the main cyclone chamber 5, the oil phase with relatively small density converges to the center under the action of radial pressure gradient force, and the water phase with relatively large density flows to the vicinity of the outer wall, due to the limited centrifugal separation intensity, the oil droplets with particle size below 40 μm cannot be separated and will flow with the water phase, and the oil droplets with particle size above 40 μm can all converge to the center to form oil core under the cyclone intensity, and then enter the oil collection chamber through the oil guide pipe 10.

[0037] As shown in Figure 2 , the water phase carrying oil droplets with particle size less than 40 μm enters the rotating cavity 8 from the main cyclone chamber 5 through the connecting pipe 14. The oil-water mixture produces rotating flow again in the rotating cavity 8, and after passing through the spin-increasing cavity 7, the rotating flow with centrifugal acceleration reaching 4000-6000 times the gravity acceleration is generated, the oil droplets quickly converge to the center to form oil core in this centrifugal field, and then flow into the oil collection chamber through the oil guide pipe 10. The separated water phase flows into the water collection chamber from the lower port of the secondary cyclone chamber 6, and finally flows out from the water outlet pipe 16.

[0038] Experimental verification: the field experiment is carried out in a certain oil field by adopting the embodiment of the application, the relative density of oil phase is 0.92, the viscosity is 3500 mPa·s at 55 DEG C, and the freezing point is about 30 DEG C. The experimental results show that when the water content is 91%, the water separation rate of the cascade cyclone assembly reaches 89%, compared with the single-stage pre-water separation device, the water separation rate is significantly improved, and the floor area is almost unchanged; compared with the use of two-stage pre-water separator in series, the pressure drop loss is reduced by about 20%.

[0039] The above is only the preferred specific embodiment of the application, but the protection scope of the application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the application, which should be covered within the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

Claims

1. A cascade vortex pre-water separation device, characterized in that, The stepped vortex equipment mainly consists of an inlet pipe (1), a guide component (2), a guide vane (3), a vortex-enhancing chamber (4), a main vortex chamber (5), a flow-stabilizing cone (13), a connecting pipe (14), a vortex-initiating chamber (8), a vortex-stabilizing chamber (7), a secondary vortex chamber (6), an oil guide pipe (10), an oil collection chamber (11), a water collection chamber (15), an oil discharge pipe (12), and a drain pipe (16).

2. The oil collection chamber (11) and the water collection chamber (15) are tanks connected vertically and can be connected by flanges and welding, with a partition (9) in the middle.

3. The separation area of ​​the cascade vortex pre-separation device consists of one main vortex chamber (5) and multiple secondary vortex chambers (6), and the main vortex chamber (5) and multiple secondary vortex chambers (6) are all located inside the water collection chamber (15).

4. The main swirling cavity (5) is an inverted cylindrical chamber, its upstream end is connected to the swirling cavity (4), its downstream sidewall is connected to multiple connecting pipes (14), and its downstream port is sealed by the stabilizing cone (13).

5. The inlet pipe (1) is connected to the swirling cavity (4), and the flow guide (2) with the hemispherical-cylindrical-conical structure is provided inside. The flow guide (2) is fixed with the flow guide (3). The inlet pipe (1), the swirling cavity (4), the flow guide (2) and the flow guide (3) are used together to make the fluid generate a swirling flow with a centrifugal acceleration of 200 to 400 times the gravitational acceleration.

6. The connecting pipe (14) is tangent to the main swirling cavity (5) and the swirling cavity (8). The connecting pipe (14), the swirling cavity (8) and the stabilizing cavity (7) are used together to generate a swirling flow with a centrifugal acceleration of 4000 to 6000 times the acceleration of gravity.

7. The number of oil guide pipes (10) according to claim 1 corresponds to the number of swirling chambers. In the main swirling chamber, the oil guide pipe (10) is located at the center of the stabilizing cone (13). In the secondary swirling chamber, the oil guide pipe (10) is located at the center of the swirling chamber (8). The function of the oil guide pipe (10) is to guide the oil nuclei gathered in each swirling chamber into the oil collecting chamber.

8. In the main swirling chamber (5) according to claim 1, the liquid flows from bottom to top, and both the water phase and the oil phase are discharged from the upper part of the swirling chamber.

9. In the secondary swirling cavity (6) according to claim 1, the liquid flows from top to bottom, the water phase is discharged from the lower part of the swirling cavity, and the oil phase flows in the opposite direction and is discharged from the upper part of the swirling cavity.

10. The secondary swirl chamber (6) according to claim 1 has 3 to 5 chambers, which are evenly distributed around the main swirl chamber (5).

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