The utility model relates to the field of engineering, in particular to downhole pumping units for oil production.
Known borehole electric diaphragm pump for oil production (see patent RU No. 2062906, CL F 04 In 47/06, 06/27/1996).
A disadvantage of the known design is the low efficiency, as well as the low resource of a flat elastic diaphragm due to the high stroke frequency, low pressure characteristic of the pump unit, the impossibility of oil production with a low level of water cut due to the low capacity of the suction valves.
The closest technical solution is a borehole electrohydraulic drive pump unit containing a submersible electric motor, a drive oil pump, a plunger working pump with suction and discharge valves, an oil tank with fine oil filters, a volume expansion compensator for oil, and a hydraulic motor, the over- and under-piston cavities of which are connected through a distributor to the suction and discharge sides of the oil pump, with a safety valve installed on the latter and a hydraulic piston vigatelya connected to the pump's plunger (patent RU №2166668, cl. F 04 B 47/08, 10.05.2001).
The disadvantage of this design is the wear of the seals of the plunger of the working pump, leading to a decrease in performance and pressure characteristics of the pump unit.
The task to which the utility model is directed is to increase the resource of the working pump, increase the pressure characteristics and performance of the pump unit.
The technical result that is achieved as a result of solving the above problem is to increase the efficiency and reliability of the borehole electro-hydraulic pump unit.
The problem is solved, and the technical result is achieved due to the fact that the borehole electrohydraulic drive pump unit contains a submersible electric motor, a drive oil pump, a plunger working pump with suction and discharge valves, an oil tank with fine oil filters, a volume expansion compensator for oil and a hydraulic motor, and the piston cavity of the cylinder of which is connected through the distributor to the suction and
to the discharge sides of the oil pump, with a safety valve installed on the latter, and the hydraulic motor piston connected to the plunger of the working pump, the electric motor provided with a tread through the shaft of which the electric motor shaft is kinematically connected to the shaft of the oil pump, an axial piston pump, plunger cylinder is installed as the oil pump the working pump is equipped with a sealed cylindrical diaphragm made of elastic material, placed in the cylinder with the formation of filled oil cavity, and the working pump plunger is installed with the possibility of reciprocating movement inside this cavity, a pressure valve is installed above the discharge valve of the plunger working pump with the formation of a cavity, the expansion joint of the oil is made in the form of a cylinder, inside of which an elastic cylindrical diaphragm is placed with the formation of an internal sealed cavity connected with the oil tank and the annular cavity surrounding the elastic diaphragm, and the cylinder expansion joint expansion Asla provided with suction and discharge valves, the suction valve on the inlet side it communicates with the surrounding space of the pump unit and the discharge valve on the outlet side thereof through a conduit communicated with the cavity between the discharge valve of the pump plunger and the discharge valve.
The unit can be equipped with additional suction valves, which can be coaxially placed in the cylinder wall of the plunger working pump and expansion joint expansion oil in one or more rows.
The implementation of the expansion joint expansion oil with suction and discharge valves and connecting the latter to the cavity between the discharge valve of the working pump and pressure valves allows you to double the productivity of the pump unit by supplying oil on the back stroke of the hydraulic motor piston, to eliminate wear of the working pump plunger seals, since the latter works in an oil environment and does not contact directly with the pumped medium, and increase the pressure characteristic of the pump unit. As the working body of the pump, a cylindrical diaphragm made of an elastic material, for example rubber, reinforced with fiberglass or Kevlar, is used, which improves the strength of the membrane, and the working body of the plunger working pump in the form of a sealed oil-filled cavity bounded by a cylindrical diaphragm of elastic material, inside of which reciprocating movement of the plunger, allows to reduce the cyclic load on the diaphragm (compared with the above diaphragm agmennym pump) and
due to this, to increase the reliability of the plunger working pump. The advantage of the proposed technical solution is that it can be widely varied by changing the diameter of the plunger of the working pump pressure characteristic and performance of the pump unit.
The implementation of the unit with additional suction valves can increase the throughput of the unit and make the design of the unit more compact, which is especially important for installations that operate in wells.
Figure 1 shows a longitudinal section of a borehole electro-hydraulic pump unit and figure 2 shows an embodiment of a suction valve with additional suction valves for a borehole electro-hydraulic pump unit using the example of a cylinder of a plunger working pump with suction valves.
The borehole electric hydraulic pump unit contains a submersible motor 1, a drive oil pump 2, a plunger working pump 4 with a suction 5 and a discharge 6 valves, an oil tank 7 with filters 8 for fine oil purification, a compensator 9 for the volume expansion of oil and a hydraulic motor 10, above (11) and the sub-piston 12 cavity of the cylinder 13 which is connected through the distributor 14 to the suction 15 and the discharge 16 sides of the oil pump 2, the safety valve 3 being installed on the latter, and the piston 17 of the hydraulic motor 10 is connected to the plow Jerome 18 of the pump 4. The motor 1 is provided with a tread 19, through which the shaft 1 of the motor shaft is kinematically connected to the drive shaft of the oil pump 2. As driving the oil pump 2 is an axial piston pump. The cylinder 20 of the plunger working pump 4 is provided with a sealed cylindrical diaphragm 21 made of elastic material placed in the cylinder 20 to form an oil-filled cavity 22, and the plunger 18 of the working pump 4 is installed with the possibility of reciprocating movement inside this cavity 22. Above the discharge valve 6 of the plunger working the pump 4 is installed with the formation of the cavity 23 pressure valve 31. The compensator 9 for the volume expansion of the oil is made in the form of a cylinder 24, inside of which is placed an elastic cylindrical I diaphragm 25 with the formation of an internal airtight cavity 26, in communication with the oil tank 7 and the annular cavity 27 surrounding the elastic diaphragm 25, and the cylinder 24 of the expansion joint 9 of the oil expansion is equipped with a suction 28 and pressure 29 valves, while the suction valve 28 from the input side it is in communication with the space surrounding the pumping unit, and the discharge valve 29 from the outlet side is communicated by means of a pipe 30 with a cavity 23 between
discharge valve 6 of the plunger working pump 4 and pressure valve 31. A borehole electro-hydraulic pump unit is installed on a string of 32 tubing (tubing).
The unit can be made with additional suction valves 5 and 28, and the suction valves 5 and 28 can be coaxially placed in the wall of the cylinders 20 and 24, respectively, of the plunger working pump 4 and the expansion joint 9 of the oil expansion in one or more rows.
The distributor 14 is connected through a pipe 33 and a channel 34, respectively, with the supra-piston cavity 11 and the sub-piston cavity 12 of the cylinder 13 of the hydraulic motor 10.
The directional mechanical switch of the distributor 14 consists of a pusher 35 and a latch 36 with a spring 37.
Oil leaks through seals from the cavity 22 are returned to the oil tank 7 through a pipe 38.
A string of 32 tubing pipes with a pump unit is lowered into a casing installed in the well. Power supply of the submersible motor is carried out by means of a cable 39, which is attached to the pipe string 32 by tubing clamps (not shown).
Downhole electrohydraulic pump unit operates as follows.
Before immersing the pump unit in the borehole of the cavity of the electric motor 1 with the tread 19 and the hydraulic drive system are filled with purified oil corresponding to the operating temperature regime.
When the pump unit is immersed in the oil reservoir, the produced fluid flows into the cavities of the cylinders 24 and 20, respectively, through the suction valves 28 and 5.
Under the influence of hydrostatic pressure, the discharge valves 29, 6 and the pressure valve 31 open and the fluid fills the tubing string 32 to the formation level.
When you turn on the motor 1, the drive oil pump 2 starts to work, which through the distributor 14 delivers oil to one of the cavities of the cylinder 13 of the hydraulic motor 10.
If oil is supplied under the piston 17, the plunger 18 moves upward, filling the volume of the oil cavity 22 and stretching the diaphragm 21 under oil pressure, and thereby displacing the liquid from the cylinder 20 through the discharge valve 6 into the cavity 23 and then through the pressure valve 31 into the tubing string 32 . When the piston 17 moves up
the volume of oil in the cavity 26 of the compensator 9 is reduced by the amount of the volume of the plunger 18 that has left the cylinder 13 of the hydraulic motor 10, therefore, the liquid through the suction valve or the suction valves 28 fills the cavity 27 of the cylinder 24 of the compensator 9.
The difference between the volumetric flow rates of the hydraulic motor 10 injected into the cylinder 13 and the oil displaced from it, due to the presence of the plunger 18 in the supra-piston cavity 11, is compensated by the change in the oil volume in the oil tank 4 and the cavity 26 of the expansion joint 9 of the oil, limited by the diaphragm 25.
When the piston 17 of the hydraulic motor 10 moves downward, the volume of oil under the diaphragm 25 in the cavity 26 increases and the liquid from the cylinder 24 through the discharge valve 29, the pipeline 30 and the pressure valve 31 enters the tubing 32.
At the same time, the cylinder 20 of the plunger working pump 4 is filled with liquid through the suction valve or the suction valves 5. When the hydraulic piston 17 reaches a certain upper or lower position, the switch of the distributor 14 is activated and the return stroke is carried out and the above-described duty cycle is repeated.
Switching of the distributor 14 during the movement of the piston 17 is due to the impact on the spool of the distributor pusher 35 in the extreme positions of the piston. “Hanging” of the spool valve in the middle position is eliminated due to the presence of the latch 36 with the spring 37, which compresses, accumulates a certain potential energy and, having overcome the resistance of the latch, moves the pusher 35 and, accordingly, the spool to one of the extreme positions.
The mechanical switch may have other designs, in particular, and in combination with a hydraulic distributor commanding the main distributor.
When the dynamic level of the liquid in the well decreases, the current protection level is set in the control station for the submersible motor 1 according to the maximum permissible level according to the depth of descent of the pump unit and power outage.
Otherwise, the pump unit is equipped with an electric motor with speed control and their reduction with a decrease in the dynamic level and, accordingly, a decrease in the supply of the pump unit at the command of the annular pressure sensor installed in the electric motor.
This utility model can be used in the oil industry and other industries where liquid is produced from wells.