CN116291359A - A dynamic cyclone pre-separation device and method for oilfield gas-bearing production fluid - Google Patents

Abstract

The invention relates to a dynamic cyclone pre-diversion device and a method for oilfield gas-containing produced liquid, wherein the device comprises the following components: the liquid inlet cylinder is internally provided with a gas control overflow pipe, a driving mechanism is arranged at the first end of the gas control overflow pipe, and a dynamic rotation element is arranged at the second end of the gas control overflow pipe; the static separation cylinder body is internally provided with an oil discharge vortex breaking table for discharging an oil phase; the liquid inlet cylinder body and the static separation cylinder body are coaxially and serially connected. The device realizes the oil-water pre-separation of the gas-containing produced liquid of the oil field by a countercurrent exhaust and concurrent oil discharge method. The countercurrent exhaust prevents free gas from forming gas core to influence the oil phase to converge towards the center of the pipeline, and the countercurrent exhaust liquid-containing gas phase and the concurrent exhaust oil phase are converged and then jointly enter the crude oil treatment system, so that the control of the liquid content of the exhaust gas is not needed.

Description

A dynamic cyclone pre-separation device and method for oilfield gas-bearing production fluid

technical field

The invention relates to a dynamic cyclone pre-water separation device and method for oilfield gas-containing production fluid, and belongs to the technical field of oil field production fluid pre-water separation.

Background technique

As the exploitation of most oilfields in my country enters the middle and late stages, coupled with the continuous increase of exploitation efforts, the water content of oilfield produced fluids is generally high. In order to reduce the impact of the large increase in produced water, the research on downhole and uphole water pre-separation technology has received extensive attention. Among them, the cyclone separator has a compact structure and high separation efficiency, and is the first choice for pre-water separation equipment in oil fields, especially offshore oil fields.

However, there are often a large amount of associated gas in the oilfield produced fluid, and the gas density is very small compared with the oil-water two-phase density. Therefore, during the cyclone separation process, the gas phase quickly converges to the center of the cyclone separator and forms a gas nucleus. The existence of nuclei prevents the oil phase from flowing out smoothly from the overflow port, causing part of the oil phase to migrate downward and then flow out from the bottom flow port. Generally, when the gas content of the incoming liquid exceeds 2%, the separation performance of the static hydrocyclone decreases rapidly. In order to reduce the negative impact of gas contained in oilfield produced liquid on the separation performance of cyclone separation equipment, the existing technology adopts the measure of gas-liquid separation first; however, in order to reduce the liquid content of the gas-liquid separator exhaust, the flow rate It needs to be less than the gas content of the incoming liquid, so that the liquid outlet still contains a certain amount of gas, usually the gas content of the liquid outlet is below 10%. With such a high gas fraction, it is obviously impossible to ensure that the cyclone separator, especially the tubular dynamic cyclone separator, works under optimal working conditions.

From the above analysis, it can be seen that the compact cyclone separation equipment is the first choice for water pre-separation in high water-cut oilfields, but the gas content of oilfield produced fluid seriously affects the separation performance of the cyclone pre-separation equipment.

Contents of the invention

In view of the above technical problems, the present invention provides a dynamic cyclone pre-separation device and method for gas-containing production fluid in oilfields. High separation performance can still be maintained.

To achieve the above object, the present invention takes the following technical solutions:

A dynamic cyclone pre-water separation device for oilfield gas-bearing production fluid, comprising:

A liquid inlet cylinder, the liquid inlet cylinder is provided with an air control overflow pipe, the first end of the air control overflow pipe is provided with a driving mechanism, and the second end is provided with a dynamic spinning element;

A static separation cylinder, the static separation cylinder is provided with an oil discharge and vortex breaker for discharging the oil phase;

The liquid inlet cylinder is coaxially connected in series with the static separation cylinder.

As for the dynamic swirl pre-separation device for gas-containing production fluid in an oil field, preferably, the dynamic swirling element includes several gradually changing helical blades uniformly arranged along the outer circumference of the gas control overflow pipe with gradually increasing pitches.

In the dynamic swirl pre-separation equipment for gas-containing production fluid in the oil field, preferably, the first part of the blade is installed on the gas control overflow pipe, and the second part faces toward the static separation cylinder Extended, in a floating state.

In the dynamic cyclone pre-separation equipment for gas-containing production fluid in the oil field, preferably, the length of the second part of the blade is 0.3-0.7 times the inner diameter of the gas-controlling overflow pipe.

In the dynamic cyclone pre-separation equipment for oilfield gas-containing production fluid, preferably, the liquid inlet cylinder is further provided with blade sleeves, and the blade sleeves are arranged outside the dynamic swirling element.

In the dynamic cyclone pre-separation device for gas-containing production fluid in an oilfield, preferably, the axial length of the blade sleeve is the same as the length of the blade.

In the dynamic cyclone pre-separation equipment for gas-containing production fluid in the oil field, preferably, the oil discharge vortex breaker is a hollow circular frustum-shaped structure, and the oil discharge vortex breaker is coaxially arranged with the static separation cylinder .

In the dynamic cyclone pre-separation equipment for oilfield gas-containing production fluid, preferably, the dynamic swirl element is arranged coaxially with the static separation cylinder.

In the dynamic cyclone pre-separation equipment for gas-containing production liquid in the oil field, preferably, the liquid inlet cylinder is provided with a liquid inlet, and the end of the static separation cylinder away from the liquid inlet cylinder is provided with a An oil discharge port and a water discharge port, the oil discharge port is arranged coaxially with the oil discharge vortex breaker.

The second aspect of the present invention provides a water separation method of the above-mentioned oilfield gas-containing production fluid dynamic swirling pre-water separation equipment, comprising the following steps:

The oilfield gas-containing production fluid enters the liquid inlet cylinder from the liquid inlet, the dynamic spinning element rotates under the drive of the driving mechanism, and the gas in the oilfield gas-containing production fluid quickly gathers into the cylinder under the action of centrifugal force. center and discharged from the air control overflow pipe; the liquid phase enters the static separation cylinder after being accelerated by the second half of the dynamic swirl element, and after the high-speed rotating fluid enters the static separation cylinder, under the action of centrifugal force The lower oil phase gradually converges towards the center and is finally discharged from the oil discharge and vortex breaker.

The present invention has the following advantages due to the adoption of the above technical scheme:

1. The present invention realizes the oil-water pre-separation of the gas-containing production fluid in the oil field by means of countercurrent exhaust and downstream oil discharge. Countercurrent exhaust prevents free gas from forming a gas nucleus and affecting the oil phase to converge toward the center of the pipeline. The liquid-containing gas phase discharged countercurrently and the oily phase discharged downstream are collected and enter the crude oil processing system together, so there is no need to control the liquid content of the discharged gas .

2. The device disclosed in the present invention has the advantages of compact structure, simple manufacturing process, and convenient maintenance. It can be directly assembled on the oil pipeline, and can also be used as an underground water pre-dividing device. Compared with the existing technology, it greatly improves the oil-water separation ability of the dynamic cyclone separation equipment for the production fluid of high gas content oilfields, and has considerable promotion value.

Description of drawings

Fig. 1 is the cross-sectional view of the dynamic cyclone pre-separation equipment for oil field gas-bearing production fluid provided by an embodiment of the present invention;

Fig. 2 is the explosion diagram of the dynamic cyclone pre-separation equipment for oilfield gas-bearing produced fluid provided by this embodiment of the present invention;

Fig. 3 is a schematic diagram of the water diversion flow direction of the dynamic cyclone pre-divider device for oilfield gas-containing production fluid provided by this embodiment of the present invention;

The marks in the figure are as follows:

1-air control overflow pipe; 2-liquid inlet cylinder; 3-dynamic spinning element; 4-blade sleeve; 5-static separation cylinder; 6-oil discharge vortex breaker; 7-oil discharge port; 8 - water outlet; 9 - liquid inlet; 10 - driving mechanism.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention are clearly and completely described below. Apparently, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without making creative efforts belong to the protection scope of the present invention.

Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the usual meanings understood by those skilled in the art to which the present invention belongs. "First", "second", "third", "fourth" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Comprising" or "comprising" and similar words mean that the elements or items appearing before the word include the elements or items listed after the word and their equivalents, without excluding other elements or items. Words such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

The present invention aims at the problem that the existing dynamic cyclone separation equipment has insufficient ability to deal with oilfield gas-containing production fluid, and proposes a dynamic cyclone pre-water separation equipment and method for oilfield gas-containing production fluid. The different physical and chemical characteristics of the three phases of water can realize the pre-water separation operation of the gas-bearing produced fluid in the oil field through the method of reverse exhaust and downstream oil recovery.

The dynamic swirl pre-separation equipment for gas-containing production fluid in the oil field disclosed by the present invention adopts the method of countercurrent exhaust and downstream oil collection, and quickly discharges the free gas entering the liquid inlet cylinder to prevent the disturbance of the gas nucleus to the oil nucleus; The two phases of oil and water are separated in a longer separation barrel to ensure that the two phases of oil and water with a smaller density difference have a long enough separation time. The discharged gas and oil are combined and enter the subsequent treatment system without controlling the liquid content of the exhaust port. Rate. The equipment is driven by the dynamic spinning element driven by the driving mechanism to drive the oil/water/gas mixture entering the device to rotate at high speed. Under the action of centrifugal force, the gas phase with very low density first converges to the center of the pipeline and is discharged from the gas control overflow pipe. The oil phase with a density similar to that of water gradually converges toward the center in the longer static separation cylinder, and is discharged from the hollow area of the oil discharge and vortex breaker at the tail of the static separation cylinder. The device of the present invention solves the problem of reduced swirl separation performance caused by the gas contained in the produced liquid. The device has a compact structure, simple manufacturing process, convenient maintenance and low pressure loss. The pre-water separation of gas production fluid provides an effective solution.

The technical solutions of the present invention will be described in detail below in conjunction with specific examples.

As shown in Fig. 1 and Fig. 2, the oilfield gas-containing production fluid dynamic swirl pre-separation equipment involved in the present invention includes:

The liquid inlet cylinder 2 is provided with an air control overflow pipe 1 inside the liquid inlet cylinder 2. The first end of the air control overflow pipe 1 is provided with a driving mechanism 10, and the second end is provided with a dynamic spin-up element 3; static separation The cylinder body 5 and the static separation cylinder body 5 are provided with an oil discharge vortex breaker 6 for discharging the oil phase; the liquid inlet cylinder body 2 and the static separation cylinder body 5 are coaxially connected in series.

In some preferred embodiments of the present invention, the dynamic swirling element 3 includes a number of gradually changing helical blades that are uniformly arranged along the outer circumference of the gas control overflow pipe 1 and whose pitch gradually increases (the gradual increase of the pitch refers to the direction from the production fluid into the blade end to the One end of the production fluid output blade gradually increases), the minimum pitch of the blade is 1 time of its outer diameter, and the maximum pitch of the blade is 2 times of its outer diameter.

Further, the first part of the vane is installed on the air control overflow pipe 1, and the second part extends toward the direction close to the stationary separation cylinder 5, and is in a suspended state. The length of the second part of the blade is 0.3-0.7 times the inner diameter of the air control overflow pipe 1. Preferably, the length of the second part of the blade is 0.5 times the inner diameter of the air control overflow pipe 1, so that the gas phase can be discharged smoothly. It is beneficial to ensure that the oil phase converges toward the center.

In some preferred embodiments, a blade sleeve 4 is also arranged inside the liquid inlet cylinder 2 , and the blade sleeve 4 is sleeved on the outside of the dynamic swirling element 3 .

Further, the axial length of the blade sleeve 4 is the same as the length of the blade.

The blade sleeve 4, the dynamic spinning element 3 and the air control overflow pipe 1 jointly form six axially independent fan-shaped areas. The fluid in the fan-shaped areas also rotates during operation, and the gas quickly gathers into the pipeline under the action of centrifugal force. center and discharged from the air control overflow pipe 1; the liquid phase (oil-water mixture) accelerated by the second half of the dynamic swirl element 3 enters the static separation cylinder 5, and the high-speed rotating fluid enters the static separation cylinder 5, and the density is relatively high The small oil phase gradually migrates to the center under the action of centrifugal force, and finally is discharged from the oil discharge and vortex breaking table 6, and the water phase is transferred to the outer ring area of the cylinder under the action of large centrifugal force, and finally discharged through the drain port 8.

As shown in FIG. 2 , in some examples, the oil discharge and vortex breaking table 6 is a hollow conical structure, and the oil discharge and vortex breaking table 6 is coaxially arranged with the stationary separation cylinder 5 .

As shown in Fig. 1, the dynamic spin-up element 3 is coaxially arranged with the static separation cylinder 5, and the diameters are kept equal. The liquid inlet cylinder 2 is connected to the end of the static separation cylinder 5 through a flange, and the other end of the static separation cylinder 5 is connected to the oil discharge port 7 through a flange. Certainly, the liquid inlet cylinder body 2 and the static separation cylinder body 5 may also be an integral fixed connection structure, and the present invention does not limit the way of their connection.

Furthermore, as shown in Figure 1, the liquid inlet cylinder 2 is provided with a liquid inlet 9, and the end of the static separation cylinder 5 away from the liquid inlet cylinder 2 is provided with an oil discharge port 7 and a water discharge port 8, and the oil discharge port 7 is coaxially arranged with oil discharge and vortex breaking table 6.

As shown in Figure 3, the present invention also provides the water separation method of the above-mentioned oilfield gas-bearing production fluid dynamic swirling pre-water separation equipment, including the following steps:

The oil field gas-containing production fluid enters the liquid inlet cylinder 2 from the liquid inlet 9, and the dynamic spinning element 3 rotates under the drive of the driving mechanism 10, and the gas in the oil field gas-containing production fluid quickly gathers to the center under the action of centrifugal force. And it is discharged from the gas control overflow pipe 1; the liquid phase enters the static separation cylinder 5 after being accelerated by the second half of the dynamic spinning element 3, and after the high-speed rotating fluid enters the static separation cylinder 5, the oil phase gradually moves toward the The center converges and is finally discharged from the oil discharge and vortex breaker 6.

The device of the invention aims at the different physical and chemical characteristics of the three phases of oil/gas/water, and realizes the pre-water separation operation of the gas-containing production fluid in the oil field by means of reverse exhaust and downstream oil collection. The specific working principle of the device is as follows:

After the oilfield gas-bearing production fluid enters the dynamic swirl pre-separation equipment, the dynamic swirling element 3 forces the production fluid to produce a strong swirl movement. Due to the density difference of the three phases of oil/gas/water, the centrifugal force generated by the swirl The gas phase with very low density first gathers to the center of the pipe, and is quickly discharged reversely from the gas control overflow pipe 1.

The liquid-containing gas phase discharged countercurrently and the oily phase discharged downstream converge and then enter the crude oil treatment system. It is not necessary to control the liquid content of the exhaust gas. The flow rate of the countercurrent exhaust gas should be greater than the gas content of the incoming flow, which can be 1.1 times the gas content. , the countercurrent exhaust volume is not limited to 1.1 times, and any method that adopts countercurrent exhaust and downstream oil collection, and the exhaust volume is greater than the gas content to eliminate the influence of the gas core on the oil-water separation performance belongs to the protection scope of the present invention.

The oil-water two-phase mixed liquid with strong swirl is separated in the longer static separation cylinder 5, which ensures that the oil-water two-phase with a small density difference has sufficient actual separation time. Among them, the water phase is transferred to the outer ring area of the separator barrel by a large centrifugal force and discharged from the drain port 8, and the oil phase with a lower density gathers in the center of the pipeline to form an oil core, and breaks the vortex from the oil discharge at the tail of the barrel The hollow area of stage 6 is discharged downstream.

The main purpose of adopting countercurrent exhaust in the present invention is to prevent excess free gas from forming gas nuclei and affecting the oil phase to converge towards the center, rather than to separate the gas phase in the mixed liquid.

The device of the invention overcomes the problem of insufficient capacity of the existing swirling flow pre-separation water equipment to process liquid water produced with high gas content, and has a compact structure, simple manufacturing process, convenient maintenance, and is suitable for long-term operation.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it can still be Modifications are made to the technical solutions described in the foregoing embodiments, or equivalent replacements are made to some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims (10)

1. A dynamic cyclone pre-separation device for gas-bearing production fluid in an oil field, characterized in that it comprises: The liquid inlet cylinder (2), the air control overflow pipe (1) is arranged inside the liquid inlet cylinder (2), and the first end of the air control overflow pipe (1) is provided with a driving mechanism (10) , the second end is provided with a dynamic spin-up element (3); A static separation cylinder (5), which is provided with an oil discharge and vortex breaker (6) for discharging the oil phase; The liquid inlet cylinder (2) is coaxially connected with the static separation cylinder (5) in series. 2. The dynamic swirl pre-separation equipment for oilfield gas-bearing production fluid according to claim 1, characterized in that, the dynamic swirling element (3) includes several Progressive helical blades with uniform arrangement and gradually increasing pitch. 3. The dynamic cyclone pre-separation equipment for oilfield gas-containing production fluid according to claim 2, characterized in that the first part of the blade is installed on the gas control overflow pipe (1), and the second part It extends toward the direction close to the stationary separation cylinder (5) and is in a suspended state. 4. The dynamic cyclone pre-separation equipment for oilfield gas-containing production fluid according to claim 3, characterized in that, the length of the second part of the blade is 0.3 of the inner diameter of the gas control overflow pipe (1) -0.7 times. 5. The dynamic cyclone pre-separation equipment for oilfield gas-containing production fluid according to claim 2, characterized in that, the liquid inlet cylinder (2) is also provided with a blade sleeve (4), and the blade The sleeve (4) is sheathed on the outside of the dynamic spinning element (3). 6 . The dynamic cyclone pre-separation equipment for oilfield gas-containing production fluid according to claim 5 , characterized in that the axial length of the blade sleeve ( 4 ) is the same as the length of the blade. 7 . 7. The dynamic cyclone pre-separation equipment for oilfield gas-containing production fluid according to claim 1, characterized in that, the oil discharge vortex breaker (6) is a hollow frustum-shaped structure, and the oil discharge vortex breaker (6) is arranged coaxially with the static separation cylinder (5). 8. The dynamic cyclone pre-separation equipment for oilfield gas-bearing production fluid according to claim 1, characterized in that, the dynamic swirling element (3) is arranged coaxially with the static separation cylinder (5). 9. The dynamic cyclone pre-separation equipment for oilfield gas-containing production fluid according to claim 1, characterized in that, the liquid inlet cylinder (2) is provided with a liquid inlet (9), and the static separation The end of the cylinder (5) away from the liquid inlet cylinder (2) is provided with an oil discharge port (7) and a drain port (8), and the oil discharge port (7) is connected to the oil discharge vortex breaker (6 ) coaxial setting. 10. A method for dividing water according to any one of claims 1-9, comprising the steps of: Oilfield gas-containing production fluid enters the liquid inlet cylinder (2) from the liquid inlet (9), and the dynamic spin-up element (3) rotates under the drive mechanism (10), and the oilfield gas-containing The gas in the production fluid quickly gathers to the center under the action of centrifugal force and is discharged from the gas control overflow pipe (1); the liquid phase enters the static separation after being accelerated by the second half of the dynamic swirl element (3). Cylinder (5), after the high-speed rotating fluid enters the static separation cylinder (5), the oil phase gradually converges towards the center under the action of centrifugal force, and is finally discharged from the oil discharge and vortex breaker (6).

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