Variable pitch spiral flow combined anti-gas process pipe column

Abstract

This invention discloses a variable pitch swirl combined gas-prevention process tubing, relating to the field of oilfield oil and gas production technology. It includes a tubing body housed within the casing, a pump mounted on the tubing body, a variable pitch spiral separation gas-prevention section mounted on the lower part of the tubing body below the pump, and a constant pressure venting section mounted on the upper part of the tubing body above the pump. The tubing body above the constant pressure venting section is connected to the tubing. This invention achieves gas separation below the pump to improve pump efficiency, while simultaneously discharging the separated gas through the annulus into the tubing at the upper part of the tubing body, thus entering the oil production process and forming a highly efficient oil production process under reasonable casing pressure.

Description

Technical Field

[0001] This invention relates to the field of oilfield oil and gas production technology, and more specifically to the field of variable pitch swirl combined gas prevention process tubing technology. Background Technology

[0002] In the mechanical oil recovery process of high gas-liquid ratio reservoirs, a large amount of free gas is released into the wellbore due to the decrease in reservoir pressure and pressure drop during production. Therefore, during pumping, both gas and liquid are introduced into the pump simultaneously. This gas influx inevitably reduces the amount of liquid entering the pump, decreasing the pump's filling coefficient and reducing pump efficiency. When the gas effect is severe, "gas lock" may even occur, where the compression and expansion of gas within the pump prevents the pump's suction and discharge valves from opening properly, resulting in no oil being extracted. This significantly reduces pump efficiency and severely impacts the normal production of the oil well. Traditionally, the solution is to install gas-prevention devices.

[0003] The patent with publication number "CN03251061.6" and patent name "Inner Cover Type Gas Prevention Device" discloses the following: An inner cover type gas prevention device has an intake port in the middle of the outer sleeve, an inner cover type defoamer, an exchange chamber and a 70-meter separation outer sleeve at the bottom, and a central tube installed in the middle to form the separation stage of the gas prevention device. The upper part of the intake port is equipped with a 12-meter discharge outer sleeve and a discharge valve assembly, and a central tube installed in the middle to form the discharge stage of the gas prevention device. Its characteristic is that the lower part of the inner cover type defoamer has an exchange chamber.

[0004] The patent with publication number "CN209704543U" and patent name "A Wellbore Gas Prevention and Control String" discloses the following: A wellbore gas prevention and control string includes a sleeve, an oil pipe installed inside the sleeve, an anti-backpressure pump installed inside the oil pipe, and an inner cover-type gas prevention device installed at the end of the anti-backpressure pump; wherein, the anti-backpressure pump includes a pump barrel and a plunger installed inside the pump barrel, a sucker rod installed inside the sleeve, and the sucker rod is connected to the plunger inside the anti-backpressure pump; the inner cover-type gas prevention device includes a vent pipe, a central pipe is provided inside the vent pipe, and an annular cavity is formed between the vent pipe and the central pipe; a centrifugal separator is installed at the upper end of the vent pipe, a plug is installed at the lower end of the vent pipe, and a liquid inlet is opened on the vent pipe, which is connected to the annular cavity.

[0005] The aforementioned patented tubing strings are long and have cumbersome procedures for lowering the central tube; therefore, it is necessary to design an efficient gas-proof structure and combined process tubing to reduce the impact of free gas on the pumping system and fully utilize the energy of free gas to improve pump efficiency. Summary of the Invention

[0006] The purpose of this invention is to solve the above-mentioned technical problems by providing a variable pitch swirl combination gas-proof process column.

[0007] To achieve the above objectives, the present invention specifically adopts the following technical solution:

[0008] The variable pitch swirl combined gas-proof process string includes a string body installed inside a casing, a pump installed on the string body, a variable pitch spiral separation gas-proof section installed on the lower part of the string body installed on the pump, and a constant pressure venting section installed on the upper part of the string body installed on the pump. The string body above the constant pressure venting section is connected to the oil pipe.

[0009] Furthermore, the variable pitch spiral separation anti-gas section includes, from top to bottom, a primary gas-liquid separation pipe fitting, a throat assembly, a secondary gas-liquid separation pipe fitting, an oil pipe short connector, and a bottom plug for the inlet screen pipe. Oil pipe couplings are provided at the connection between the primary gas-liquid separation pipe fitting and the throat assembly, and at the connection between the secondary gas-liquid separation pipe fitting and the oil pipe short connector. The throat assembly and the secondary gas-liquid separation pipe fitting are sealed together, and the oil pipe short connector and the bottom plug for the inlet screen pipe are sealed together.

[0010] Furthermore, the primary gas-liquid separation pipe fitting includes a primary gas-liquid separation connector, a steel ball, a gas collecting pipe, and a primary separation pipe body. The primary gas-liquid separation connector is sealed to the primary separation pipe body. The gas collecting pipe is disposed inside the primary separation pipe body, with a portion of the gas collecting pipe extending into the primary gas-liquid separation connector. The steel ball is disposed at the end of the gas collecting pipe located inside the primary gas-liquid separation connector.

[0011] The throat assembly includes a throat and a throat connector. One end of the throat connector is sealed and sleeved with the secondary gas-liquid separation pipe fitting, and the other end of the throat connector is connected to the primary separation pipe body through an oil pipe coupling.

[0012] The secondary gas-liquid separation pipe fitting includes a secondary spiral gas-liquid separation connector, a steel ball, a variable pitch spiral rod, and a secondary separation pipe body. One end of the secondary spiral gas-liquid separation connector is connected to a throat connector, and the other end is connected to the secondary separation pipe body. The variable pitch spiral rod is disposed within the secondary separation pipe body, with one end extending into the secondary spiral gas-liquid separation connector. The steel ball is located within the secondary separation pipe body.

[0013] The end of the variable pitch screw rod inside the multi-stage spiral gas-liquid separator.

[0014] Furthermore, the variable pitch screw is disposed within the secondary separation tube, and the variable pitch screw includes a hollow screw core and variable pitch screw blades disposed on the screw core.

[0015] Furthermore, the constant pressure exhaust section is an exhaust valve installed on the tubing body. The exhaust valve includes a valve body, a valve seat communicating with the interior of the valve body, a valve core installed in the valve seat, and a spring installed at the valve core.

[0016] The beneficial effects of this invention are as follows:

[0017] 1. Pump-down gas-proof (variable pitch spiral separation) section: Significantly reduces the length of the device and the workload of connecting the core tube inside the tubing during operation; the variable pitch spiral blade structure improves separation efficiency and simplifies the device; it makes full use of the downhole liquid column pressure difference and the pump suction pressure difference to improve separation efficiency; the structure is simple and the operation is safe and reliable.

[0018] 2. Pump (exhaust valve) section: The exhaust pressure is set according to the well conditions to maintain stable casing pressure; the casing separation gas enters the tubing through the exhaust valve downhole and is centrally processed in the production process, which is safe and environmentally friendly; it solves the problem of high casing pressure affecting pump efficiency. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the variable pitch swirl combination anti-gas process column of the present invention;

[0020] Figure 2 This is a schematic diagram of the variable pitch spiral separation anti-gas section of the present invention;

[0021] Figure 3 yes Figure 2 Schematic diagram of the structure at point AA;

[0022] Figure 4 yes Figure 2 Schematic diagram of the structure at BB;

[0023] Figure 5 yes Figure 2 A schematic diagram of the structure at point I;

[0024] Figure 6 This is a schematic diagram of the constant pressure exhaust section;

[0025] Attached reference numerals: 1-oil pipe, 2-casing, 3-oil pump, 4-constant pressure venting section, 4-1-valve body, 4-2-valve seat, 4-3-valve core, 4-4-spring, 5-variable pitch spiral separator anti-gas section, 5-1-first stage gas-liquid separator connector, 5-2-steel ball, 5-3-gas collecting pipe, 5-4-first stage separator pipe body, 5-5-throat pipe, 5-6-oil pipe coupling, 5-7-throat pipe connector, 5-8-second stage spiral gas-liquid separator connector, 5-9-variable pitch spiral rod, 5-10-second stage separator pipe body, 5-11-oil pipe short connector, 5-12-bottom plug of inlet screen pipe. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0028] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0029] In the description of the embodiments of the present invention, it should be noted that the terms "inner," "outer," "upper," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, and are only used for the convenience of describing the present invention and simplifying the description.

[0030] This is not intended to 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 should not be construed as a limitation of the present invention.

[0031] Example 1

[0032] like Figures 1 to 6 As shown, this embodiment provides a variable pitch swirl combined gas-proof process string, including a string body disposed in a casing 2, an oil pump 3 disposed on the string body, a variable pitch spiral separation gas-proof part 5 disposed on the lower part of the string body disposed on the oil pump 3, and a constant pressure exhaust part 4 disposed on the upper part of the string body disposed on the oil pump 3. The string body above the constant pressure exhaust part 4 is connected to the oil pipe 1.

[0033] In this embodiment, while achieving the goal of improving pump efficiency by separating gas under the pump, the separated gas is discharged into the oil tubing through the annulus of the tubing and enters the oil production process at the top of the tubing body, thus forming a high-efficiency oil production under reasonable casing pressure.

[0034] Example 2

[0035] This embodiment is a further optimization based on Embodiment 1, specifically:

[0036] The variable pitch spiral separation gas-proof part 5 includes, from top to bottom, a primary gas-liquid separation pipe fitting, a throat assembly, a secondary gas-liquid separation pipe fitting, an oil pipe short connector 5-11, and an inlet screen pipe bottom plug 5-12. Oil pipe couplings 5-6 are provided at the connection between the primary gas-liquid separation pipe fitting and the throat assembly, and at the connection between the secondary gas-liquid separation pipe fitting and the oil pipe short connector 5-11. The throat assembly and the secondary gas-liquid separation pipe fitting are sealed together, and the oil pipe short connector 5-11 and the inlet screen pipe bottom plug 5-12 are sealed together.

[0037] The primary gas-liquid separation pipe fitting includes a primary gas-liquid separation connector 5-1, a steel ball 5-2, a gas collecting pipe 5-3, and a primary separation pipe body 5-4. The primary gas-liquid separation connector 5-1 is sealed and sleeved with the primary separation pipe body 5-4. The gas collecting pipe 5-3 is disposed inside the primary separation pipe body 5-4, and a portion of the gas collecting pipe 5-3 extends into the primary gas-liquid separation connector 5-1. The steel ball 5-2 is disposed at the end of the gas collecting pipe 5-3 located inside the primary gas-liquid separation connector 5-1.

[0038] The throat assembly includes a throat 5-5 and a throat connector 5-7. One end of the throat connector 5-7 is sealed and sleeved with the secondary gas-liquid separation pipe fitting, and the other end of the throat connector 5-7 is connected to the primary separation pipe body 5-4 through an oil pipe coupling 5-6.

[0039] The secondary gas-liquid separation pipe fitting includes a secondary spiral gas-liquid separation connector 5-8, a steel ball 5-2, a variable pitch spiral rod 5-9, and a secondary separation pipe body 5-10. One end of the secondary spiral gas-liquid separation connector 5-8 is connected to the throat connector 5-7, and the other end of the secondary spiral gas-liquid separation connector 5-8 is connected to the secondary separation pipe body 5-10. The variable pitch spiral rod 5-9 is disposed inside the secondary separation pipe body 5-10, and one end of the variable pitch spiral rod 5-9 extends into the secondary spiral gas-liquid separation connector 5-8. The steel ball 5-2 is located at the end of the variable pitch spiral rod 5-9 inside the secondary spiral gas-liquid separation connector 5-8.

[0040] The variable pitch screw rod 5-9 is installed inside the secondary separation tube 5-10. The variable pitch screw rod 5-9 includes a hollow screw core rod and variable pitch screw blades installed on the screw core rod.

[0041] In this embodiment, when the fluid in the well reaches the location of the spiral separation structure, the first gas-liquid separation is achieved under the combined action of the centrifugal force of the swirling flow and the pressure difference at the liquid level. In addition, when the fluid passes through the variable pitch spiral blades, the pressure drop is further generated due to the expansion of the fluid space, which promotes a second gas-liquid separation. The separated gas enters the inner cavity of the spiral core rod through the through hole on the core rod of the spiral separation structure, and then passes through the secondary spiral gas-liquid separation joint.

[0042] 5-8 enters the annulus of the oil jacket; through the throat 5-5, it enters the first-stage separation tube 5-4, where the liquid and gas are separated by the throat effect. The gas enters the annulus of the oil jacket through the gas collecting pipe 5-3 and the first-stage gas-liquid separation connector 5-1, while the liquid enters the oil pump through the first-stage gas-liquid separation connector 5-1.

[0043] Example 3

[0044] This embodiment is a further optimization based on embodiment 1 or 2, specifically:

[0045] The constant pressure exhaust section 4 is an exhaust valve installed on the main body of the tubing column. The exhaust valve includes a valve body 4-1, a valve seat 4-2 communicating with the interior of the valve body 4-1, a valve core 4-3 installed in the valve seat 4-2, and a spring 4-4 ​​installed at the valve core 4-3.

[0046] In this embodiment, the separated gas is discharged into the tubing at the top of the tubing body through the annulus and enters the oil production process, maintaining a stable annulus pressure. This allows the pumping pump 3 to operate under a reasonable pressure difference between the annulus and the tubing, achieving the purpose of preventing gas from entering the pump and venting and stabilizing the pressure at the top of the pump. This improves the efficiency of mechanical oil production while ensuring the safe recovery of casing gas.

Claims

1. A variable pitch swirl combined gas-proof process string, characterized in that, It includes a tubing body installed in the casing (2), an oil pump (3) installed on the tubing body, a variable pitch spiral separation gas-proof part (5) installed on the lower tubing body of the oil pump (3), and a constant pressure exhaust part (4) installed on the upper tubing body of the oil pump (3). The tubing body above the constant pressure exhaust part (4) is connected to the oil pipe (1). The variable pitch spiral separation gas-proof part (5) includes a primary gas-liquid separation pipe fitting, a throat assembly, a secondary gas-liquid separation pipe fitting, an oil pipe short connector (5-11), and an inlet screen pipe bottom plug (5-12) arranged sequentially from top to bottom. Oil pipe couplings (5-6) are provided at the connection between the primary gas-liquid separation pipe fitting and the throat assembly, and at the connection between the secondary gas-liquid separation pipe fitting and the oil pipe short connector (5-11). The throat assembly and the secondary gas-liquid separation pipe fitting are sealed together, and the oil pipe short connector (5-11) and the inlet screen pipe bottom plug (5-12) are sealed together. The primary gas-liquid separation pipe fitting includes a primary gas-liquid separation connector (5-1), a steel ball (5-2), a gas collecting pipe (5-3), and a primary separation pipe body (5-4). The primary gas-liquid separation connector (5-1) is sealed and sleeved with the primary separation pipe body (5-4). The gas collecting pipe (5-3) is disposed inside the primary separation pipe body (5-4), and part of the gas collecting pipe (5-3) extends into the primary gas-liquid separation connector (5-1). The steel ball (5-2) is disposed at the end of the gas collecting pipe (5-3) located inside the primary gas-liquid separation connector (5-1). The throat assembly includes a throat (5-5) and a throat connector (5-7). One end of the throat connector (5-7) is sealed and sleeved with the secondary gas-liquid separation pipe fitting, and the other end of the throat connector (5-7) is connected to the primary separation pipe body (5-4) through an oil pipe coupling (5-6). The secondary gas-liquid separation pipe fitting includes a secondary spiral gas-liquid separation connector (5-8), a steel ball (5-2), a variable pitch spiral rod (5-9), and a secondary separation pipe body (5-10). One end of the secondary spiral gas-liquid separation connector (5-8) is connected to the throat connector (5-7), and the other end of the secondary spiral gas-liquid separation connector (5-8) is connected to the secondary separation pipe body (5-10). The variable pitch spiral rod (5-9) is disposed inside the secondary separation pipe body (5-10), and one end of the variable pitch spiral rod (5-9) extends into the secondary spiral gas-liquid separation connector (5-8). The steel ball (5-2) is located at the end of the variable pitch spiral rod (5-9) inside the secondary spiral gas-liquid separation connector (5-8). The variable pitch screw rod (5-9) is installed inside the secondary separation tube (5-10). The variable pitch screw rod (5-9) includes a hollow screw core rod and variable pitch screw blades installed on the screw core rod. The axial width of the variable pitch screw blades is smaller than the blade pitch, and the pitch of the variable pitch screw blades increases sequentially from bottom to top.

2. The variable pitch swirl combined gas-proof process string according to claim 1, characterized in that, The constant pressure exhaust section (4) is an exhaust valve installed on the column body. The exhaust valve includes a valve body (4-1), a valve seat (4-2) communicating with the inside of the valve body (4-1), a valve core (4-3) installed in the valve seat (4-2), and a spring (4-4) installed at the valve core (4-3).

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