Special-shaped plunger rod type gas-proof oil well pump

Abstract

The invention relates to the technical field of oilfield development, in particular to a special-shaped plunger rod type gas-proof oil well pump. Comprising an outer cylinder main body, and an inner cylinder main body is arranged in the outer cylinder main body; the inner cylinder main body comprises an upper inner pump cylinder (5) and a lower inner pump cylinder (12); the lower end of the upper inner pump cylinder (5) is in threaded connection with a ventilation coupling (6), the lower inner pump cylinder (12) and a fixed valve (15) in sequence; a special-shaped plunger group is arranged in the inner cylinder main body; and the upper end of the special-shaped plunger group is in threaded connection with a pull rod (4). According to the special-shaped plunger rod type gas-proof oil well pump, the problem that an existing CO2 flooding oil well is prone to forming'gas locking 'along with the increase of displacement time, so that normal production of the oil well cannot be achieved is solved, the influence of oil well gas with the high gas-liquid ratio on the oil well pump can be reduced, the'gas locking' phenomenon is avoided, production of the oil well is maintained, and the service life of the oil well is prolonged. And the production time rate of the oil producing well under the high gas-liquid ratio well condition is improved.

Description

Technical Field

[0001] The invention relates to the technical field of oilfield development, in particular to a special-shaped plunger rod type air-proof oil pump. Background Art

[0002] CO2 flooding technology demonstrates the key advantages of low cost, high effectiveness, and high environmental value in effectively utilizing unconventional, low-permeability reservoirs. However, as CO2 flooding time increases in oil wells, the gas content in the wellbore increases rapidly, and the oil well pump becomes increasingly affected by the gas. The gas undergoes reciprocating compression and expansion within the pump chamber, preventing the fixed and floating valves from opening, creating a "gas lock" that disrupts normal oil well production. Therefore, anti-gas lift technology is needed to reduce the impact of gas on the oil well pump and improve lift efficiency.

[0003] To this end, a special-shaped plunger rod type air-proof oil pump was invented and applied to high gas-liquid ratio oil wells under gas drive and other displacement methods. Through the special-shaped structure of the plunger, the gas adheres to the recessed part of the plunger and enters the upper pump barrel and is discharged as the plunger moves, eliminating the impact of gas and ensuring the normal production of the oil well. Summary of the Invention

[0004] This invention proposes a special-shaped plunger rod-type gas-proof oil well pump to address the problem of existing CO2 flooding oil wells prone to "gas lock" as displacement time increases, preventing normal production in the wells. The purpose of this invention is to provide a special-shaped plunger rod-type gas-proof oil well pump that can reduce the impact of gas from high gas-liquid ratio oil wells on the pump, avoid the occurrence of "gas lock", maintain production in the oil well, and improve the production rate of oil wells under high gas-liquid ratio well conditions.

[0005] Provided is a special-shaped plunger rod type air-proof oil pump, comprising an outer cylinder body, wherein an inner cylinder body is housed in the outer cylinder body; the inner cylinder body comprises an upper inner pump barrel and a lower inner pump barrel, the lower end of the upper inner pump barrel being threadedly connected to a ventilation coupling, a lower inner pump barrel and a fixed valve in sequence; a special-shaped plunger group is housed in the inner cylinder body; the upper end of the special-shaped plunger group is threadedly connected to a pull rod.

[0006] Preferably, the special-shaped plunger group includes a first-level plunger, the lower end of the first-level plunger is connected to the second-level plunger and the third-level plunger in sequence; the upper end of the first-level plunger is connected to the upstream movable valve; the lower end of the third-level plunger is threadedly connected to the downstream movable valve; the upper end of the upstream movable valve is threadedly connected to the pull rod.

[0007] Preferably, the first-stage plunger is formed by connecting the upper cylindrical section and the lower inverted conical section; the second-stage plunger is formed by connecting the upper positive conical section, the middle cylindrical section and the lower inverted conical section; the third-stage plunger is formed by connecting the upper positive conical section and the lower cylindrical section.

[0008] Preferably, the outer cylinder body includes an upper outer pump cylinder and a lower outer pump cylinder; the outer pump cylinder and the lower outer pump cylinder are threadedly connected through a support seat to form the outer cylinder body.

[0009] Preferably, a soft sealing ring is placed between the lower end of the ventilation coupling and the inner surface of the support seat; a rigid sealing component is placed on the outer surface of the upper end of the ventilation coupling, and the rigid sealing component is threadedly connected to the ventilation coupling.

[0010] Preferably, the first-stage plunger, the second-stage plunger, and the third-stage plunger are clearance-fitted with the upper inner pump barrel, the ventilation coupling, and the lower inner pump barrel; the upper inner pump barrel, the ventilation coupling, the lower inner pump barrel are clearance-fitted with the upper outer pump barrel, the support seat, and the lower outer pump barrel; the support seat is interference-fitted with the rigid sealing assembly.

[0011] Preferably, a liquid outlet hole is opened on the upper inner pump barrel.

[0012] Preferably, a plunger liquid outlet hole is opened on the tapered section at the upper end of the upstream movable valve.

[0013] The present invention has at least the following beneficial effects: The invention provides a special-shaped plunger rod type air-proof oil pump, when working, the pull rod drives the first-stage plunger, the second-stage plunger and the third-stage plunger to perform reciprocating motion inside the upper inner pump barrel, the ventilation coupling and the lower inner pump barrel, so as to lift the produced fluid; at the same time, the gas in the produced fluid is stored in the recessed connection of the first-stage plunger, the second-stage plunger and the second-stage plunger and the third-stage plunger when the plungers of each stage reciprocate, and moves with the first-stage plunger, the second-stage plunger and the third-stage plunger to the ventilation coupling to release the gas, thereby reducing the gas volume inside the inner pump barrel and reducing the influence of the gas on the floating valve and the fixed valve, thereby realizing air lock prevention during the operation of the oil pump; when inspecting the pump, the plunger can drive the inner pump barrel to be extracted from the outer pump barrel as the sucker rod is lifted, and then the inner pump barrel is lifted to the wellhead position together with the sucker rod to replace the oil pump without lifting the oil pipe and the outer pump barrel, so that the oil well can be operated without a fixed pipe string, thereby reducing the operation time and cost and saving the operation fee.

[0014] The present invention adopts a three-plunger integrated special-shaped plunger structure, and the plungers at each level are connected by a recessed structure, thereby realizing the storage and discharge of gas.

[0015] The ventilation coupling cooperates with the support seat, rigid sealing assembly and soft sealing ring to fix and seal the inner and outer pump barrels. By lifting and lowering the sucker rod during the non-working process, the inner and outer pump barrels can be effectively separated and sealed.

[0016] Through on-site application, the present invention can improve pump efficiency by 20%, eliminate air lock, and reduce workload and operation time by 50% compared with conventional pump inspection operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings herein are incorporated into and constitute a part of the specification. These drawings illustrate embodiments consistent with the present invention and, together with the specification, are used to explain the technical solutions of the present invention.

[0018] Figure 1 This is a structural diagram of a special-shaped plunger rod type air-proof oil well pump according to the present invention; Figure 2 It is a structural schematic diagram of the special-shaped plunger of the present invention.

[0019] In the figure: 1-upper outer pump barrel, 2-support seat, 3-lower outer pump barrel, 4-pull rod, 5-upper inner pump barrel, 6-ventilation coupling, 7-rigid sealing assembly, 8-upper movable valve, 9-soft sealing ring, 10-first-stage plunger, 11-second-stage plunger, 12-lower inner pump barrel, 13-third-stage plunger, 14-downstream movable valve, 15-fixed valve. DETAILED DESCRIPTION

[0020] The present invention is further described below with reference to the accompanying drawings: like Figure 1 、 Figure 2 As shown, a special-shaped plunger rod type air-proof oil pump comprises an outer tube body and an inner tube body, wherein the inner tube body is installed in the outer tube body; the outer tube body comprises an upper outer pump barrel 1 and a lower outer pump barrel 3; the upper outer pump barrel 1 and the lower outer pump barrel 3 are threadedly connected through a support seat 2 to form the outer tube body; the inner tube body comprises an upper inner pump barrel 5 and a lower inner pump barrel 12, and the lower end of the upper inner pump barrel 5 is threadedly connected to the ventilation coupling 6, the lower inner pump barrel 12, and the fixed valve 15 in sequence.

[0021] The inner cylinder body is equipped with a special-shaped plunger group, which includes a first-level plunger 10, the lower end of which is connected to a second-level plunger 11 and a third-level plunger 13 in sequence; the upper end of the first-level plunger 10 is connected to an upstream valve 8; the lower end of the third-level plunger 13 is threadedly connected to a downstream valve 14; Figure 2 As shown, the first-stage plunger 10 is formed by connecting the upper cylindrical section and the lower inverted conical section; the second-stage plunger 11 is formed by connecting the upper regular conical section, the middle cylindrical section and the lower inverted conical section; the third-stage plunger 13 is formed by connecting the upper regular conical section and the lower cylindrical section; the upper end of the upstream movable valve 8 is threadedly connected to the pull rod 4.

[0022] A soft sealing ring 9 is placed between the lower end of the ventilation coupling 6 and the inner surface of the support seat 2. The function of the soft sealing ring 9 is to isolate the liquid in the annular space formed by the upper outer pump barrel 1, the upper inner pump barrel 5, and the ventilation coupling 6 from the liquid in the annular space formed by the lower outer pump barrel 3, the ventilation coupling 6, and the lower inner pump barrel 12; a rigid sealing component 7 is placed on the outer surface of the upper end of the ventilation coupling 6, the function of which is to ensure that the support seat 2 can be fixed to the ventilation coupling 6 and does not move within the specified force range; the rigid sealing component 7 is threadedly connected to the ventilation coupling 6.

[0023] The first-stage plunger 10, second-stage plunger 11, and third-stage plunger 13 are clearance-fitted with the upper inner pump barrel 5, ventilation coupling 6, and lower inner pump barrel 12; the upper inner pump barrel 5, ventilation coupling 6, and lower inner pump barrel 12 are clearance-fitted with the upper outer pump barrel 1, support seat 2, and lower outer pump barrel 3; the support seat 2 is interference-fitted with the rigid sealing assembly 7. A liquid outlet is formed on the upper inner pump barrel 5; and a plunger liquid outlet is formed on the upper tapered section of the upper movable valve 8.

[0024] When the special-shaped plunger rod type air-proof oil pump of the present invention is working, the sucker rod drives the pull rod to perform reciprocating motion, and the pull rod drives the first-stage plunger, the second-stage plunger, and the third-stage plunger to perform reciprocating motion inside the upper inner pump barrel, the ventilation coupling, and the lower inner pump barrel, and the lifting of the produced fluid is achieved by opening and closing the upper movable valve and the lower movable valve; at the same time, the gas in the produced fluid enters the gap between the inner pump barrel and the plungers at each stage when the plungers at each stage reciprocate, and is stored in the concave connection of the first-stage plunger, the second-stage plunger, and the tapered section of the second-stage plunger and the third-stage plunger as the plungers move, and the gas passes through the first-stage plunger, the second-stage plunger, and the third-stage plunger as the plungers move. The continuous movement of the plug continuously moves with the depression to the ventilation coupling 6 for storage and release. The gas is stored in the ventilation coupling 6 during the upstroke of the oil pump, and the gas is released during the downstroke and is lifted to the ground with the gas and liquid, reducing the gas volume inside the inner pump barrel, reducing the impact of the gas on the floating valve and the fixed valve, and realizing anti-gas lock during the operation of the oil pump; when inspecting the pump, the plunger can drive the inner pump barrel to be extracted from the outer pump barrel as the sucker rod is lifted, and then the inner pump barrel is lifted to the wellhead position together with the sucker rod to replace the oil pump. There is no need to pull out the oil pipe and the outer pump barrel, and the oil well can be operated without a fixed pipe string, which reduces the operation time and cost and saves operation expenses.

[0025] This invention utilizes a three-piston, integrated, special-shaped plunger structure. Each plunger is connected by a recessed structure, enabling gas storage and discharge. A ventilation coupling, combined with a support seat, a rigid sealing assembly, and a soft sealing ring, secures and seals the inner and outer pump barrels. The inner and outer pump barrels can be effectively separated and set by raising and lowering the sucker rod during non-operating operations. Example 1

[0026] Taking the target well A1 in the periphery of Daqing Oilfield, which is seriously affected by gas, as an example, the effect comparison between the special-shaped plunger rod anti-gas pumping pump of the present invention and the ordinary pumping pump is specifically described. Step 1: Take the target well A1 as an example. This well is a gas-driven beam pumping well. It uses a Ø32mm conventional pump for production. The stroke rate is 3 strokes per minute, which is the minimum stroke rate. The pump efficiency at the start of production is 50%. Step 2: As the gas-liquid ratio increases, the impact of oil well pump gas increases. When the gas-liquid ratio is ≥50m³ / m³, the liquid production drops rapidly, the stroke frequency is 3 times per minute, which is the lowest stroke frequency, the pump efficiency drops to 20%, and gas locks often occur. Step 3: After replacing a Ø32 model special-shaped plunger rod type air-proof oil pump for production, the stroke rate was 3 times per minute, the lowest stroke rate, the pump efficiency was 40%, and no air lock occurred. The pump efficiency was significantly improved compared to before the pump was replaced. Example 2

[0027] Taking the target well A2 in the periphery of Daqing Oilfield, which is seriously affected by gas, as an example, the comparison of the pump inspection operation of the special-shaped plunger rod anti-gas pump of the present invention and the ordinary pumping pump is specifically described. Step 1: Take the target well A2 as an example. This well is a gas-driven walking beam pumping unit with a minimum stroke rate of 3 times per minute. A special-shaped plunger rod anti-gas pumping unit is used to produce until the pump inspection time, and then the oil well pump inspection operation is carried out.

[0028] Step 2: During the pump inspection, the plunger is lifted up along with the sucker rod to drive the inner pump barrel out of the outer pump barrel. The inner pump barrel is then lifted up to the wellhead together with the sucker rod to replace the oil pump without having to pull out the oil pipe or outer pump barrel.

[0029] Step 3: After the oil well pump is replaced, it is lowered into the outer pump to the predetermined position and the seal is set, thus completing a pump inspection operation. This reduces the workload and operation time by 50% compared with conventional pump inspection operations.

[0030] The special structure of the special-shaped plunger and inner pump barrel prevents gas lock, reduces the impact of gas, and ensures efficient production of the oil well. During operation, there is no need to pull out the oil pipe and outer pump barrel, reducing operation costs and saving operation time.

[0031] It should be noted that, in the description of the present invention, unless otherwise specified or limited, "installation" and "connection" should be understood in a broad sense. This includes but is not limited to direct connection, detachable connection, integral connection, mechanical connection, and welding. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are protected by the present invention. While various embodiments of the present invention have been described above, the above descriptions are intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or technological improvements in the marketplace, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A special-shaped plunger rod type anti-air pump, comprising an outer cylinder body, wherein the outer cylinder body is provided with an inner cylinder body; characterized in that: The inner cylinder body comprises an upper inner pump barrel (5) and a lower inner pump barrel (12); the lower end of the upper inner pump barrel (5) is threadedly connected to a ventilation coupling (6), a lower inner pump barrel (12) and a fixed valve (15) in sequence; a special-shaped plunger group is installed in the inner cylinder body; the upper end of the special-shaped plunger group is threadedly connected to a pull rod (4).

2. The special-shaped plunger rod type air-proof oil pump according to claim 1, characterized in that: The special-shaped plunger group comprises a first-stage plunger (10), the lower end of the first-stage plunger (10) being sequentially connected to a second-stage plunger (11) and a third-stage plunger (13); the upper end of the first-stage plunger (10) being connected to an upper movable valve (8); the lower end of the third-stage plunger (13) being threadedly connected to a downstream movable valve (14); and the upper end of the upstream movable valve (8) being threadedly connected to a pull rod (4).

3. The special-shaped plunger rod type air-proof oil well pump according to claim 2, characterized in that: The first-stage plunger (10) is formed by connecting an upper cylindrical section and a lower inverted conical section.

4. The special-shaped plunger rod type air-proof oil well pump according to claim 2, characterized in that: The secondary plunger (11) is formed by connecting an upper positive conical section, a middle cylindrical section and a lower inverted conical section.

5. The special-shaped plunger rod type air-proof oil well pump according to claim 2, characterized in that: The three-stage plunger (13) is formed by connecting an upper positive conical section and a lower cylindrical section.

6. The special-shaped plunger rod type air-proof oil well pump according to claim 1, characterized in that: The outer cylinder body comprises an upper outer pump cylinder (1) and a lower outer pump cylinder (3); the outer pump cylinder (1) and the lower outer pump cylinder (3) are threadedly connected via a support seat (2) to form the outer cylinder body.

7. The special-shaped plunger rod type air-proof oil well pump according to claim 6, characterized in that: A soft sealing ring (9) is placed between the lower end of the ventilation coupling (6) and the inner surface of the support seat (2); a rigid sealing component (7) is placed on the outer surface of the upper end of the ventilation coupling (6), and the rigid sealing component (7) is threadedly connected to the ventilation coupling (6).

8. A special-shaped plunger rod type air-proof oil well pump according to claim 1, 2, 6 or 7, characterized in that: The first-stage plunger (10), the second-stage plunger (11), and the third-stage plunger (13) are clearance-matched with the upper inner pump barrel (5), the ventilation coupling (6), and the lower inner pump barrel (12); the upper inner pump barrel (5), the ventilation coupling (6), and the lower inner pump barrel (12) are clearance-matched with the upper outer pump barrel (1), the support seat (2), and the lower outer pump barrel (3); and the support seat (2) and the rigid sealing component (7) are interference-matched.

9. The special-shaped plunger rod type air-proof oil well pump according to claim 1, characterized in that: The upper inner pump barrel (5) is provided with a liquid outlet.

10. The special-shaped plunger rod type air-proof oil well pump according to claim 1, characterized in that: A plunger liquid outlet hole is provided on the conical section at the upper end of the upstream movable valve (8).

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