RU2184270C1 - Oil-well plunger pump - Google Patents

Abstract

FIELD: oil producing industry; pumping of viscous emulsions and gas-liquid mixtures. SUBSTANCE: pump has fixed cylinder and plunger and delivery valve. Upper suction valve is installed on plunger including upper and lower pistons connected by branch pipe with ports for taking in crude oil and with through channel for passing of fluid. Upper and lower pistons are interconnected non-rigidly. Lower piston can reciprocate relative to upper piston. EFFECT: possibility of use of sucker-rod pumps of large diameter for transfer of emulsified oil and gas-liquid mixtures in large amounts. 1 dwg

Description

 The proposed solution relates to the oil industry and can be used in oil production for pumping out viscous emulsion oils and gas-liquid mixtures from production wells.

 The downhole plunger pump comprises a cylinder with a lower suction valve located in its lower part, providing hydraulic connection of the cylinder with the liner and a plunger device located in it, including the upper and lower pistons connected by a pipe with windows for receiving oil and a through channel for fluid passage, and also discharge and suction valves. The upper and lower pistons are not rigidly interconnected, the lower piston has the possibility of reciprocating movement relative to the upper piston.

 The technical solution relates to techniques for oil production and can be used for pumping viscous emulsion oils and gas-liquid mixtures from high-yield oil wells.

 A well-known sucker rod pumping unit for pumping emulsion oils from producing wells (1).

 The disadvantage of this design is the narrow scope. The unit can be used with a certain percentage of water in oil. The closest in technical solution is a deep pump with separate receptions for oil and water (2).

 The main disadvantage of this design is the limited withdrawal of fluid from the reservoir. This design of the pump cannot provide oil extraction in the amount of 100 tons / day and above, since the overall dimensions of the pump do not allow the use of sucker rod pumps with a plunger diameter of 70 mm and above in oil wells.

 The objective of the invention is the creation of a pump for pumping viscous emulsion oils and gas-liquid mixtures in large volumes.

 The problem is solved by placing the upper suction valve for oil on a movable plunger device, which allows the use of rod pumps with a large diameter.

 The drawing schematically shows the design of a borehole plunger pump. The device comprises a cylinder (1) with radial holes (2) for receiving oil from the annulus of the well. In the lower part of the cylinder (1), a suction valve for water (3) entering the cylinder from the shank (4) is installed. Inside the cylinder (1) there is a plunger device comprising an upper piston (5) with a discharge valve (6) and a lower piston (7). Pistons (5,7) are not rigidly interconnected by a special pipe (8) with windows (9) for receiving oil and a through channel for fluid passage. A conical seat (10) of the upper suction valve (11) is installed inside the nozzle (8), which is located below the seat (10) and is made in the form of a cone-type spool. The valve (11) is rigidly connected to the lower piston (7) and has the possibility of reciprocating movement inside the pipe (8) from the seat (10) to the stop installed in the lower part of the pipe (8).

 Downhole plunger pump operates as follows. When the pistons (5 and 7) are in the lowest position, the discharge valve (6) is still open, and the suction valves (3 and 11) are closed. Under the piston (7) there is produced water, the pressure under it is equal to the pressure in the cavity of the elevator (12). The piston (5) overlaps the radial holes (2) and the cylinder cavity (1) is disconnected from the annulus of the well. In the annular space of the cylinder (1) there is oil under pressure equal to the pressure in the annulus of the well at a depth of pump descent. When the column string (13) moves up, the discharge valve (6) closes and the upper suction valve (11) opens. The cavity of the working chamber under the piston (7) communicates with the annular space of the cylinder (1) and the pressure in them becomes equal. The piston (7) together with the piston (5) will begin to move up and the pressure under it will drop to the pressure at the intake valve (3).

 The valve (3) will open and produced water from the liner (4) will begin to flow into the pump cylinder. The water suction cycle will continue until the lower end of the piston (5) reaches the holes (2) in the cylinder (1). At this point, oil from the annulus will begin to flow into the working chamber of the pump. The pressure under the piston (7) will increase to the pressure in the annulus at the inlet of the oil into the cylinder and the suction valve (3) will close. A higher pressure in the annulus of the well compared with the pressure at the intake of the valve (3) is due to the fact that fluids with different densities are extracted from the liner (4) and the annulus of the well. The oil suction cycle will continue until the plunger device has reached its highest position. The piston (7) is located under the holes (2), the valve (11) is open, and the valves (3 and 6) are closed. In the working chamber of the pump, oil is located in the upper part, in the bottom - formation water. The volume of water that fills the lower part of the cylinder (1) is equal to the amount of water delivered to the bottom of the well in one cycle of the pump. This correspondence between the selection and the flow of fluid is achieved by fitting the piston (5) relative to the holes (2). Depending on the water cut of the oil, the holes (2) overlap with the upper, middle or lower part of the piston (5) at its lowest position.

 When the rods go down, the valve (11) closes and under the piston (7) the pressure starts to increase, and at the moment of equal pressure in the working chamber of the pump and in the elevator (12), the discharge valve (6) opens, and oil from the cylinder (1) flows into elevator cavity. This process continues until the piston (7) reaches the separation of oil and water in the cylinder (1). Subsequently, when the rod string is moved downward, water enters the elevator pipes. The flow of water from the cylinder into the elevator continues until the plunger device reaches its lowest position. When the rod string moves up, the pump cycle will be repeated.

Sources of information
1. SU 1236161 A1, 1986.

 2. SU 1323743 A2, 1987.

Claims (1)

 A downhole plunger pump comprising a stationary cylinder, a plunger with a discharge valve, upper and lower suction valves, characterized in that the upper suction valve is installed on the plunger, including the upper and lower pistons, connected by a pipe with windows for receiving oil and a through channel for fluid passage, moreover, the upper and lower pistons are not rigidly interconnected and the lower piston has the ability to reciprocate relative to the upper piston.