High-gas-liquid-ratio electric submersible pump drainage gas production pipe column mechanism

Abstract

The invention provides a high-gas-liquid-ratio electric submersible pump water drainage and gas production pipe column mechanism which comprises a casing pipe used for supporting the well wall of an oil and gas well, an oil pipe column and a gas treatment assembly, the oil pipe column is arranged in the casing pipe, and an oil sleeve annulus is formed between the oil pipe column and the casing pipe to store natural gas. The gas treatment assembly comprises a gas filtering part used for separating free gas and a gas treatment unit used for compressing bubbles in oil, the gas treatment unit is arranged in the gas filtering part, the tubing string penetrates through the gas filtering part to be connected with the gas treatment unit, and a gap is reserved between the gas filtering part and the sleeve so that redundant gas can be exhausted. Free gas can be preliminarily separated before oil gas in an oil-gas well enters the oil pipe through the gas filtering piece, the content of the gas entering the oil pipe is reduced, the gas entering the oil pipe is further compressed through the gas processing unit, and therefore the form and size of the free gas are changed, a gas-liquid mixture is homogenized, the diameter of bubbles is reduced, and the gas inlet amount is reduced. And airlock is prevented from being formed in the flow channel.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil and gas production equipment, and particularly relates to a high gas-liquid ratio electric submersible pump drainage gas recovery pipe column mechanism. BACKGROUND

[0002] Currently, in the process of collecting crude oil and natural gas, a tubing string is usually used to collect the liquid and natural gas of an oil and gas well and to lift the liquid and natural gas in the oil and gas well to the ground. When a centrifugal pump in a third centrifugal pump pipe column rotates, high and low pressure zones are formed inside the flow passage. As the intake amount increases, gas bubble aggregation begins to form in the low pressure zone in the pump impeller. As the intake amount further increases, the amount of gas bubble aggregation gradually increases, eventually occupying the entire flow passage in the third centrifugal pump pipe column, and forming a gas lock in the flow passage, which can seriously affect the head, displacement and efficiency of the third centrifugal pump. When the intake amount is too large, most of the space in the impeller flow passage of the third centrifugal pump is occupied by gas, the third centrifugal pump stops discharging liquid, and the damage probability of the third centrifugal pump unit increases, thereby causing the pump efficiency to decrease and the pump lifting capacity to decrease. SUMMARY

[0003] In view of the above problems, the present application provides a high gas-liquid ratio electric submersible pump drainage gas recovery pipe column mechanism, which comprises:

[0004] a casing for supporting the well wall of an oil and gas well;

[0005] a tubing string arranged in the casing and forming an oil-casing annulus with the casing to store natural gas;

[0006] a gas treatment assembly comprising a gas filter for separating free gas and a gas treatment unit for compressing gas bubbles in oil, the gas treatment unit being arranged in the gas filter, the tubing string being connected with the gas treatment unit through the gas filter, and a gap being left between the gas filter and the casing to discharge excess gas.

[0007] Optionally, the gas filter is a flow guide cover, which is invertedly arranged on the tubing string to allow oil and gas to enter the flow guide cover and complete oil and gas separation by gravity.

[0008] Optionally, the gas treatment unit comprises a suction port and a gas processor for compressing gas bubbles in oil, the suction port being located in the gas filter, the suction port being connected with the gas processor, and the tubing string being connected with the gas processor.

[0009] Optionally, a plurality of inclined through holes are arranged on the two side walls of the suction port to allow oil and gas to enter the suction port from the plurality of inclined through holes.

[0010] Optionally, the angle between the central axis of the plurality of inclined through holes and the vertical axis of the suction inlet is 30-60 degrees.

[0011] Optionally, the apparatus further comprises an electric pump assembly connected to the end of the tubing string to lift the tubing string, the electric pump assembly being connected to the gas treatment unit, and part of the electric pump assembly being located in the gas filter.

[0012] Optionally, the electric pump assembly comprises a first centrifugal pump, a second centrifugal pump and a third centrifugal pump connected in series and located in the gas filter, the third centrifugal pump being connected to the end of the tubing string, and the displacement of the first centrifugal pump, the second centrifugal pump and the third centrifugal pump decreasing in turn.

[0013] Optionally, the apparatus further comprises a tubing hanger, one end of the tubing hanger being connected to the wellhead of the oil and gas well, and the other end of the tubing hanger being connected to the tubing string through a tubing.

[0014] Optionally, the apparatus further comprises a permanent magnet motor, a cable and a protector, one end of the protector being connected to the gas filter, and the other end of the protector being connected to the permanent magnet motor, and the cable being connected to the permanent magnet motor.

[0015] Optionally, the apparatus further comprises a screen pipe, a packer, an oil sand filter and an anti-disconnection joint connected in series, one end of the screen pipe being connected to the permanent magnet motor, and the packer being attached to the inner wall of the casing.

[0016] The high gas-liquid ratio electric submersible pump drainage gas recovery tubing string mechanism of the present application can make the oil and gas in the oil and gas well preliminarily separate the free gas before entering the tubing, reduce the gas content entering the tubing, further compress the entering gas through the gas treatment unit, change the form and size of the free gas, homogenize the gas-liquid mixture, reduce the bubble diameter, reduce the gas intake, and avoid the formation of gas lock in the flow passage. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0018] Figure 1 A schematic diagram of the high gas-liquid ratio electric submersible pump drainage gas recovery tubing string mechanism in the embodiment of the present application is shown.

[0019] Figure 2 A schematic diagram of the suction inlet of the gas treatment unit in the embodiment of the present application is shown.

[0020] In the figure, 1 - casing, 2 - tubing string, 3 - gas treatment assembly, 31 - gas filter, 32 - gas treatment unit, 322 - suction port, 321 - gas processor, 323 - through hole, 4 - electric pump assembly, 41 - first centrifugal pump, 42 - second centrifugal pump, 5 - tubing hanger, 43 - third centrifugal pump, 7 - permanent magnet motor, 8 - cable, 6 - protector, 9 - screen pipe, 10 - packer, 11 - oil sand filter, 12 - anti-drop joint. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0022] As shown in Figure 1 The present application provides a high gas-liquid ratio electric submersible pump drainage gas recovery tubing string mechanism, which comprises a casing 1 for supporting the well wall of an oil and gas well, a tubing string 2 and a gas treatment assembly 3 for filtering gas in oil and gas. The tubing string 2 is arranged in the casing 1 and forms an oil jacket annulus with the casing 1 to store natural gas. The gas treatment assembly 3 comprises a gas filter 31 for separating free gas and a gas treatment unit 32 for compressing gas bubbles in oil. The gas treatment unit 32 is arranged in the gas filter 31. The tubing string 2 is connected with the gas treatment unit 32 through the gas filter 31. A gap is left between the gas filter 31 and the casing 1 to discharge excess gas. The gas filter 31 can separate free gas in oil and gas in the oil and gas well before the oil and gas enter the tubing, thereby reducing the gas content in the tubing. The gas treatment unit 32 further compresses the entering gas, thereby changing the form and size of free gas, homogenizing the gas-liquid mixture, reducing the bubble diameter and reducing the gas intake, and avoiding the formation of gas lock in the flow passage.

[0023] As shown in Figure 1 and Figure 2As shown, in an embodiment, the gas filter 31 is a flow guide cover, which is invertedly sleeved on the oil pipe column 2, so that the oil gas enters the flow guide cover and separates the oil gas by gravity. The inverted flow guide cover separates the free gas by gravity, that is, the heavy oil flows into the gas treatment unit 32 from the bottom of the flow guide cover, and the lighter part of the free gas is left in the flow guide cover. The free gas is separated before the oil gas in the oil well enters the oil pipe, so as to reduce the gas content in the oil pipe and reduce the probability of gas lock in the oil pipe. It should be noted that the opening of the inverted flow guide cover is arranged opposite to the wellhead of the oil well, the opening of the inverted flow guide cover is upward and close to the wellhead, and the height of the inverted flow guide cover can be set according to actual needs. The inverted flow guide cover separates the free gas before the gas enters the gas treatment unit 321 by gravity, so as to preliminarily separate the free gas before the oil gas in the oil well enters the oil pipe and reduce the gas content in the oil pipe.

[0024] In an embodiment, the gas treatment unit 32 includes a suction port 322 and a gas treatment unit 321 for compressing the gas bubbles in the oil. The suction port 322 is located in the gas filter 31, the suction port 322 is connected with the gas treatment unit 321, and the oil pipe column 2 is connected with the gas treatment unit 321. The entering gas can be distributed more uniformly through the suction port 322, and the uniform gas enters the gas treatment unit 321 again, which compresses the gas, changes the shape and size of the free gas, homogenizes the gas-liquid mixture, reduces the bubble diameter, reduces the gas intake, and avoids the formation of gas lock in the flow channel. The suction port 322 is located below the inside of the inverted flow guide cover. Optionally, the gas treatment unit 321 is designed as a mixed flow, which improves the tolerance of the pump to the free gas, can pressurize the mixing of the gas and the liquid in the pump cavity, and can make the gas saturation solubility in the liquid reach the user's satisfaction value without causing cavitation. The maximum processing capacity of free gas is 45%, and the gas-liquid mixture is easily homogenized.

[0025] In an embodiment, a plurality of inclined through holes 323 are arranged on the two side walls of the suction port 322, so that the oil gas enters the suction port 322 from the plurality of inclined through holes 323. The oil gas in the oil well enters the gas treatment unit 321 from the inclined through holes 323, further separates the gas from the well fluid, and reduces the gas content in the oil pipe by uniformly arranging a plurality of inclined through holes 323 on the suction port 322. Specifically, the inclined through holes 323 are arranged to make the oil gas in the oil well in the inverted flow guide cover enter the suction port 322 from the inclined through holes 323, form a vortex, fall into the bottom of the suction port 322, enter the suction port 322 from the bottom of the suction port 322, and then enter the gas treatment unit 321. The gas is further compressed from the well fluid, and cooperates with the inverted flow guide cover to separate the free gas before entering the gas treatment unit 321 twice, so as to reduce the gas content entering the centrifugal pump. Under certain conditions, the oil gas separation efficiency can reach 95%.

[0026] In an embodiment, the angle between the central axis of the plurality of inclined through holes 323 and the vertical axis of the suction port 322 is 30°-60°. Alternatively, the angle is 30°, 40°, 50°, or 60°. In this embodiment, the angle is 60°. The oil and gas in the oil and gas well in the inverted flow guide cover enter the suction port 322 from the inclined through holes 323, form a vortex, and fall into the suction port 322, so as to make the oil and gas enter the gas processor 321 for further compression treatment.

[0027] In an embodiment, an electric pump assembly 4 for lifting oil and gas and extruding gas in the oil and gas is further included. The electric pump assembly 4 is connected with the end of the oil pipe column 2 to lift the oil pipe column 2. The electric pump assembly 4 is connected with the gas processing unit 32, and part of the electric pump assembly 4 is located in the gas filter 31. When lifting the well fluid containing free gas by the electric pump assembly 4, the pressure gradually increases from the first stage pump at the lower end to the last stage centrifugal pump at the upper end, and the total volume of gas and liquid gradually decreases. On the one hand, the pump type can be adapted to the change of the total volume of oil and gas, and the overall efficiency of the pump is improved. On the other hand, the capacity of the electric pump assembly for processing gas is improved. In addition, the pump in the present application is a wide-width pump. Compared with the conventional radial pump, the wide-width pump expands the blade opening and the flow passage, greatly expands the optimal displacement range, and then can select various combinations of the gas processor 321, the wide-width pump, and the conventional pump according to the actual needs and the actual effect of cooperation with the gas and liquid processing assembly, improve the tolerance of the centrifugal pump to free gas, reduce the formation of gas lock, and improve the lifting efficiency of the oil pipe column 2.

[0028] In an embodiment, the electric pump assembly 4 comprises a first centrifugal pump 41, a second centrifugal pump 42 and a third centrifugal pump 43 connected in series and located in the gas filter 31, the third centrifugal pump 43 is connected to the end of the tubing string 2, and the displacement of the first centrifugal pump 41, the second centrifugal pump 42 and the third centrifugal pump 43 decreases in turn. Specifically, the centrifugal pump is a wide-width pump or a conventional pump. Compared with the conventional radial pump, the wide-width pump expands the blade opening, expands the flow passage by more than 30%, and greatly expands the optimal displacement range. The conventional radial pump is suitable for the gas volume content of the fluid entering the pump being less than 10%, and the wide-width pump is suitable for the gas volume content being up to 20%. In this embodiment, each centrifugal pump is a multi-stage tower combination. The centrifugal pumps in the multi-stage tower combination can be variously combined by selecting gas treatment pumps, wide-width pumps and conventional pumps according to actual needs and the actual effect of cooperation with the gas filter 31 and the gas treatment unit 32, thereby improving the tolerance of the multi-stage centrifugal pump to free gas, reducing the formation of gas lock, and improving the lifting efficiency of the water drainage gas recovery tubing string. In addition, the first centrifugal pump 41, the second centrifugal pump 42 and the third centrifugal pump 43 can improve the lifting capacity of oil production, thereby improving the efficiency of exploitation. In addition, the first centrifugal pump 41, the second centrifugal pump 42 and the third centrifugal pump 43 form a pyramid-shaped pump.

[0029] In an embodiment, the tubing hanger 5 is further included, one end of the tubing hanger 5 is connected to the wellhead of the oil and gas well, and the other end is connected to the tubing string 2 through the tubing. The tubing string 2 is fixed to the wellhead through the tubing hanger 5, and the third centrifugal pump 43 connected to the first centrifugal pump 41 and the second centrifugal pump 42 can improve the lifting capacity of oil production, thereby improving the efficiency of exploitation.

[0030] In an embodiment, the permanent magnet motor 7, the cable 8 and the protector 6 are further included, one end of the protector 6 is connected to the gas filter 31, the other end is connected to the permanent magnet motor 7, and the cable 8 is connected to the permanent magnet motor 7. Specifically, the third centrifugal pump 43 is connected to the electric pump unit through the tubing coupling, and the permanent magnet motor 7 is connected to the power source outside the well through the cable.

[0031] In an embodiment, further comprising a screen pipe 9, a packer 10, an oil sand filter 11 and a drop prevention joint 12 connected in sequence, one end of the screen pipe 9 is connected with the permanent magnet motor 7, and the packer 10 is attached to the inner wall of the casing 1. It should be noted that the protector 6 is used to provide lubrication protection and torque transmission output for the permanent magnet motor 7, and to balance the internal and external pressures, one end of the permanent magnet motor 7 away from the wellhead is connected with the screen pipe 9, one end of the screen pipe 9 away from the permanent magnet motor 7 is connected with the packer 10, and one end of the permanent magnet motor 7 away from the wellhead is connected with the screen pipe 9. With the above scheme, the screen pipe 9 is used to separate the impurities in the well fluid, preventing the impurities from entering the permanent magnet motor 7 and the electric pump unit, affecting the service life of the permanent magnet motor 7 and the electric pump unit. One end of the packer 10 away from the screen pipe 9 is connected with the oil sand filter 11, and one end of the oil sand filter 11 away from the packer 10 is connected with the drop prevention joint 12. One end of the packer 10 away from the screen pipe 9 is connected with the oil sand filter 11. With the above scheme, the oil sand filter 11 is used to filter the well fluid in the oil and gas well, blocking the formation sand outside the oil sand filter 11, so that the sand content of the well fluid entering the oil sand filter 11 is reduced, thereby reducing the damage to the permanent magnet motor 7 and the electric pump unit. Due to the unstable connection between the electric pump assembly 4 and the permanent magnet motor 7 under long-term work, the components between the oil pipe string 2 are not stable, causing the components to fall off or break at the connection. Once the electric pump assembly 4 connection falls off or breaks, the electric pump assembly 4, the permanent magnet motor 7 or other components will fall to the bottom of the oil and gas well. In the process of fishing, not only is it difficult to fish, but also the fishing cost is increased. The drop prevention function is realized through the drop prevention joint 12. The screen pipe 9 is used to separate the impurities in the well fluid, preventing the impurities from entering the permanent magnet motor 7, affecting the service life of the permanent magnet motor 7. The screen pipe 9 can be a steel pipe having a plurality of through holes 323, and the well fluid enters through the through holes 323. The packer 10 is used to seal the oil-casing annulus between the oil pipe string 2 and the casing 1. The screen pipe 9 and the packer 10 can be connected by threads, and the type of the packer 10 can be a double-packer.

[0032] In summary, the casing 1 is used to support the well wall of the oil and gas well to ensure the drilling process and the normal operation of the entire oil and gas well after completion. The oil-casing annulus formed between the oil pipe string 2 and the casing 1 is used to store natural gas. In the present application, the gas treatment assembly 3 separates the free gas in the well fluid entering the oil pipe, reducing the gas content entering the oil pipe. The electric pump assembly 4 changes the gas treatment capacity of the centrifugal pump, improves the tolerance of the centrifugal pump to free gas, reduces the formation of gas lock, improves the lifting efficiency of the drainage gas recovery string, and finally the liquid and natural gas are pumped out from the bottom of the oil and gas well through the third centrifugal pump 43 assembly.

[0033] The principle of the present application is that the well fluid of the oil and gas well enters the inverted flow cone through the upward opening of the inverted flow cone, the oil and gas in the inverted flow cone separates the free gas by gravity, the free gas is preliminarily separated before the oil and gas in the oil and gas well enters the oil pipe, the gas content in the oil pipe is reduced, then the well fluid of the inverted flow cone enters the suction port 322, enters the gas processor 321 through the suction port 322, the gas processor 321 achieves the purpose of further compressing the gas, changes the form and size of the free gas, homogenizes the gas-liquid mixture, reduces the bubble diameter, continuously pressurizes the gas-liquid mixture, compresses the gas into the liquid, finally, the well fluid enters the electric pump assembly 4, the internal pressure of the electric pump assembly 4 formed by the second centrifugal pump 42 is sequentially and gradually increased, so that the total volume of the gas-liquid in the multi-stage centrifugal pump is gradually reduced, thereby on the one hand, the pump type can adapt to the change of the total volume of the oil and gas, the total efficiency of the pump is improved, on the other hand, the gas processing capacity of the electric pump assembly 4 is improved, finally the tolerance of the multi-stage centrifugal pump to the free gas is improved, the formation of gas lock is reduced, and the lifting efficiency of the drainage gas recovery string is improved.

[0034] Although the present application is described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalent ones; 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 embodiments of the present application.

Claims

1. A high gas-liquid ratio electric submersible pump drainage and gas extraction tubing mechanism, characterized in that, include: Casing used to support the wellbore of oil and gas wells (1); The tubing string (2) is located inside the casing (1) and forms an annulus between it and the casing (1) to store natural gas. The gas treatment assembly (3) includes a filter element (31) for separating free gas and a gas treatment unit (32) for compressing air bubbles in oil. The gas treatment unit (32) is disposed inside the filter element (31). The oil pipe string (2) passes through the filter element (31) and is connected to the gas treatment unit (32). A gap is left between the filter element (31) and the sleeve (1) to allow excess gas to be discharged.

2. The high gas-liquid ratio electric submersible pump drainage and gas extraction tubing mechanism according to claim 1, characterized in that, The filter element (31) is a flow guide, which is inverted and sleeved on the oil pipe column (2) so that oil and gas can enter the flow guide and use its gravity to complete the oil and gas separation.

3. The high gas-liquid ratio electric submersible pump drainage and gas extraction tubing mechanism according to claim 1, characterized in that, The gas processing unit (32) includes an intake port (322) and a gas processor (321) for compressing air bubbles in the oil. The intake port (322) is located inside the filter element (31) and is connected to the gas processor (321). The oil pipe column (2) is connected to the gas processor (321).

4. The high gas-liquid ratio electric submersible pump drainage and gas extraction tubing mechanism according to claim 3, characterized in that, Multiple inclined through holes (323) are provided on both sides of the suction port (322) so that oil and gas can enter the suction port (322) through the multiple inclined through holes (323).

5. The high gas-liquid ratio electric submersible pump drainage and gas extraction tubing mechanism according to claim 4, characterized in that, The angle between the central axis of the plurality of inclined through holes (323) and the vertical axis of the suction port (322) is 30°-60°.

6. The high gas-liquid ratio electric submersible pump drainage and gas extraction tubing mechanism according to claim 1, characterized in that, It also includes an electric pump assembly (4), which is connected to the end of the tubing string (2) to lift the tubing string (2), and the electric pump assembly (4) is connected to the gas processing unit (32), with a portion of the electric pump assembly (4) located within the gas filter (31).

7. The high gas-liquid ratio electric submersible pump drainage and gas extraction tubing mechanism according to claim 6, characterized in that, The electric pump assembly (4) includes a first centrifugal pump (41), a second centrifugal pump (42) and a third centrifugal pump (43) that are connected to each other and located in the filter element (31). The third centrifugal pump (43) is connected to the end of the oil tubing string (2). The displacement of the first centrifugal pump (41), the second centrifugal pump (42) and the third centrifugal pump (43) decreases sequentially.

8. The high gas-liquid ratio electric submersible pump drainage and gas extraction tubing mechanism according to claim 6, characterized in that, It also includes a tubing hanger (5), one end of which is connected to the wellhead of the oil and gas well, and the other end is connected to the tubing string (2) through a tubing.

9. The high gas-liquid ratio electric submersible pump drainage and gas extraction tubing mechanism according to claim 1, characterized in that, It also includes a permanent magnet motor (7), a cable (8) and a protector (6), one end of which is connected to the air filter (31) and the other end of which is connected to the permanent magnet motor (7), and the cable (8) is connected to the permanent magnet motor (7).

10. The high gas-liquid ratio electric submersible pump drainage and gas extraction tubing mechanism according to claim 9, characterized in that, It also includes a screen tube (9), a packer (10), an oil sand filter (11), and an anti-drop connector (12) connected in sequence. One end of the screen tube (9) is connected to the permanent magnet motor (7), and the packer (10) is attached to the inner wall of the sleeve (1).

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