A sucker rod unloading device

Abstract

A sucker rod unloading device is disclosed, wherein the pump diameter of the upper pump barrel is smaller than that of the lower pump barrel. The upper pump barrel, the reducing pump barrel connector, and the lower pump barrel are connected in sequence. The upper piston rod, the reducing piston connector, and the lower hollow piston are connected in sequence. The upper piston rod passes into the upper pump barrel, and the lower hollow piston is located in the lower pump barrel. The upper part of the upper piston rod has a sucker rod connector. A breathing chamber is formed between the upper piston rod and the inner wall of the lower pump barrel. The reducing piston connector has a connecting groove. The breathing chamber communicates with the interior of the lower hollow piston through the connecting groove, allowing leakage fluid between the upper piston rod and the upper pump barrel, and between the lower hollow piston and the lower pump barrel, to flow downward through the interior of the lower hollow piston. The lower pump barrel is inserted into the outer pipe. The lower part of the reducing pump barrel connector is connected to the upper part of the outer pipe. The side wall of the reducing pump barrel connector has a vertical flow channel. An annular channel is formed between the lower pump barrel and the outer pipe. The vertical flow channel communicates with the annular channel, eliminating the influence of casing pressure on its unloading effect.

Description

Technical Field

[0001] This invention relates to an oil pumping device for oil fields, specifically a sucker rod unloading device. Background Technology

[0002] A reciprocating rod pump oil extraction system used in oil fields includes a pumping unit, sucker rod, pump, and tubing. The pumping unit is installed on the surface, while the sucker rod, pump, and tubing are installed inside the wellbore. The pumping unit drives the pump to reciprocate, pumping crude oil from the well to the surface. In deep and ultra-deep wells, the pumping unit and sucker rod bear heavy loads.

[0003] To address this, technicians researched a sucker rod load reduction device, installed on the tubing and sucker rod between the wellhead and the pump to reduce the load on the sucker rod and the pumping unit above its installation location. This sucker rod load reduction device utilizes the pressure difference between the tubing and casing at its installation location to generate a load reduction effect. Its load reduction effect is influenced by the casing pressure; when the casing fluid level is high, the load reduction effect is poor, and if the casing pressure is at the wellhead (which occurs when the casing is diluted), there is no load reduction effect. Summary of the Invention

[0004] The purpose of this invention is to design a sucker rod unloading device to eliminate the influence of casing pressure on its unloading effect and reduce the sucker rod load above its installation position.

[0005] The objective of this invention is achieved as follows: It includes an upper piston rod, an upper pump barrel, a reducing pump barrel connector, a reducing piston connector, a lower hollow piston, a lower pump barrel, and an outer tube. The pump diameter of the upper pump barrel is smaller than that of the lower pump barrel. The upper pump barrel, the reducing pump barrel connector, and the lower pump barrel are connected sequentially. The upper piston rod, the reducing piston connector, and the lower hollow piston are also connected sequentially. The upper piston rod passes through the upper pump barrel, and the lower hollow piston is located inside the lower pump barrel. The upper part of the upper piston rod has a sucker rod connector. The upper piston rod and the upper pump barrel are sealed together, and the lower hollow piston and the lower pump barrel are sealed together. A breathing chamber is formed between the inner walls of the upper piston rod and the lower pump barrel due to their diameter difference. The reducing piston... The connector has a connecting groove, through which the breathing chamber communicates with the interior of the lower hollow piston, allowing leakage fluid between the upper piston rod and the upper pump barrel, and between the lower hollow piston and the lower pump barrel, to flow downwards through the interior of the lower hollow piston. The lower pump barrel is inserted into the outer pipe, and the lower part of the reducing pump barrel connector is connected to the upper part of the outer pipe. The side wall of the reducing pump barrel connector has a vertical flow channel, forming an annular channel between the lower pump barrel and the outer pipe. The vertical flow channel communicates with the annular channel. The vertical flow channel and the annular channel are the outflow channels for well fluid extracted by the pumping equipment installed at the lower part of the sucker rod unloading device.

[0006] The beneficial effects of this invention are as follows: When used in conjunction with a hollow oil pump, the inlet pressure of the hollow oil pump is almost zero during operation. The upper end face of the lower hollow piston is connected to the inlet of the hollow oil pump, eliminating the influence of casing pressure on its load reduction effect. Even when the casing pressure is high and the casing is diluted to reduce viscosity, a large upward thrust can be generated at the installation point of this invention, reducing the load on the sucker rod above this invention. It can be used in conjunction with the dilution and viscosity reduction process on the casing pump to extract heavy oil. Attached Figure Description

[0007] Figure 1 This is an assembly diagram of an embodiment of the present invention. Implementation

[0008] The following is combined with Figure 1 Embodiments of the present invention will be described.

[0009] like Figure 1 As shown, an embodiment of the present invention includes an upper piston rod 2, an upper pump cylinder 3, a reducing pump cylinder connector 4, a reducing piston connector 5, a lower hollow piston 6, a lower pump cylinder 7, and an outer tube 8. The pump diameter of the upper pump cylinder 3 is smaller than that of the lower pump cylinder 7. The upper pump cylinder 3, the reducing pump cylinder connector 4, and the lower pump cylinder 7 are connected in sequence. The upper piston rod 2, the reducing piston connector 5, and the lower hollow piston 6 are connected in sequence. The upper piston rod 2 passes into the upper pump cylinder 3, and the lower hollow piston 6 is located inside the lower pump cylinder 7. The upper part of the upper piston rod 2 has a sucker rod connector 1. The upper piston rod 2 and the upper pump cylinder 3 are sealed together, and the lower hollow piston 6 and the lower pump cylinder 7 are sealed together. A breathing chamber 7-1 is formed between the inner walls of the upper piston rod 2 and the lower pump cylinder 7 due to the difference in their diameters. The reducing piston connector 5 has a connecting... The breathing chamber 7-1 is connected to the interior of the lower hollow piston 6 via the connecting groove 5-1, allowing the leakage fluid between the upper piston rod 2 and the upper pump barrel 3 and between the lower hollow piston 6 and the lower pump barrel 7 to flow downward through the interior of the lower hollow piston 6. The lower pump barrel 7 is placed inside the outer pipe 8, and the lower part of the reducing pump barrel connector 4 is connected to the upper part of the outer pipe 8. The side wall of the reducing pump barrel connector 4 has a vertical flow channel 4-1, forming an annular channel 8-1 between the lower pump barrel 7 and the outer pipe 8. The vertical flow channel 4-1 and the annular channel 8-1 are connected. The vertical flow channel 4-1 and the annular channel 8-1 are the outflow channels for the well fluid extracted by the pumping equipment installed at the lower part of the sucker rod unloading device.

[0010] This invention is installed in the middle region of the sucker string and used in conjunction with a hollow sucker pump. The lower part of the lower hollow piston 6 is connected to the upper part of the reciprocating motion part of the hollow sucker pump, and the lower part of the outer tube 8 is connected to the upper part of the fixed part of the hollow sucker pump. The interior of the lower hollow piston 6 is connected to the inlet of the hollow sucker pump through the central tube on the hollow sucker pump. Under the operation of the hollow sucker pump, the pressure on the upper end face of the lower hollow piston 6 is essentially zero, that is, the load reduction effect of this invention is independent of the casing pressure. Therefore, this invention can generate an upward thrust at the installation point of the tubing string, thereby reducing the load on the sucker rod and the sucker unit.

[0011] When a dilution process is implemented in a heavy oil well, the added thin oil fills the casing and forms a large liquid column pressure inside the casing. For the present invention, the liquid column pressure formed by the added thin oil inside the casing will not act on the upper end face of the lower hollow piston 6, and the pressure on the upper end face of the lower hollow piston 6 remains essentially zero. Therefore, the present invention will not affect the load reduction effect when diluting the casing to reduce viscosity and pump heavy oil.

[0012] When both the present invention and the hollow pump are installed in the middle region of the tubing string, the interior of the lower hollow piston 6 is connected to the inlet of the hollow pump through the central pipe on the hollow pump. This allows the leakage fluid generated between the upper piston rod and the upper pump barrel 3, and between the lower hollow piston 6 and the lower pump barrel (7), to flow back to the inlet of the hollow pump and be recovered by the hollow pump. Therefore, the present invention eliminates the deficiency of existing sucker rod unloading devices that result in production loss and can improve oil well production.

[0013] The structure of the hollow oil pump is as disclosed in Figure 9 (electrically heated heavy oil pump) of SY / T 7083-2016. There are various structures of hollow oil pumps. Hollow oil pumps with a central channel, a circulating oil pumping channel, or full-bore or non-full-bore hollow oil pumps can all be used in conjunction with this invention.

[0014] The piston (rod) and pump barrel sealing refers to compliance with the requirements specified in GB / T 17607 standard. Pump diameter refers to the inner diameter of the oil pump barrel.

Claims

1. A sucker rod unloading device, characterized in that: Including above Piston rod (2), upper pump barrel (3), reducing pump barrel connector (4), reducing piston connector (5), lower hollow piston (6), lower pump barrel (7), outer tube (8). The pump diameter of the upper pump barrel (3) is smaller than that of the lower pump barrel (7). The upper pump barrel (3), reducing pump barrel connector (4), and lower pump barrel (7) are connected in sequence. The upper piston rod (2), reducing piston connector (5), and lower hollow piston (6) are connected in sequence. The upper piston rod (2) is inserted into the upper pump barrel (3), and the lower hollow piston (6) is located in the lower pump barrel (7). There is a sucker rod connector (1) on the upper part of the upper piston rod (2). The upper piston rod (2) and the upper pump barrel (3) are sealed together. The lower hollow piston (6) and the lower pump barrel (7) are sealed together. A breathing chamber is formed between the inner walls of the upper piston rod (2) and the lower pump barrel (7) due to the difference in their diameters. There is a connecting rod on the reducing piston connector (5). The breathing chamber is connected to the interior of the lower hollow piston (6) through the connecting groove (5-1), so that the leakage fluid between the upper piston rod (2) and the upper pump barrel (3) and between the lower hollow piston (6) and the lower pump barrel (7) can flow downward through the interior of the lower hollow piston (6). The lower pump barrel (7) is placed in the outer tube (8). The lower part of the reducing pump barrel joint (4) is connected to the upper part of the outer tube (8). There is a vertical flow channel (4-1) on the side wall of the reducing pump barrel joint (4). An annular channel (8-1) is formed between the lower pump barrel (7) and the outer tube (8). The vertical flow channel (4-1) is connected to the annular channel (8-1). The vertical flow channel (4-1) and the annular channel (8-1) are the outflow channels of the well fluid extracted by the pumping equipment installed in the lower part of the sucker rod unloading device. The sucker rod unloader is installed in the middle region of the sucker string and is used in conjunction with the hollow sucker pump. The lower part of the lower hollow piston (6) is connected to the upper part of the reciprocating motion part of the hollow sucker pump, and the lower part of the outer tube (8) is connected to the upper part of the fixed part of the hollow sucker pump. The interior of the lower hollow piston (6) is connected to the inlet of the hollow sucker pump through the central tube on the hollow sucker pump.

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