RU2683428C1 - Oil well pumping unit - Google Patents

Abstract

FIELD: oil and gas industry.SUBSTANCE: invention relates to the technique of oil production, in particular to the technique of lifting the production of wells, namely water-gas-oil emulsions, and concerns the design of well pumping units. Installation contains a submersible electrocentrifugal pump with an electric motor installed in the well on the tubing string and located above them to suppress pressure pulsations of a pneumo-spring compensator. Piston of the latter is spring-loaded from the inside by a package of series-connected disc springs. They have such a power characteristic that the force of a package of series-connected cup springs and the pressure of an inert gas on the piston create a resulting restoring force with a working section of a given small – quasi-zero rigidity. Container with compressed inert gas is installed above the pneumatic spring compensator. It contains a membrane with a pointed piercer, equipped with a return spring, abutting one end against the container body with a compressed inert gas, and the other on the stop ring in the body of the pointed piercer. Sharp end of the punch is directed to the membrane. At the same time, it is possible to organize the movement of scrap along the guide when dropping it into tubing from the surface. It is possible to move the scrap along a tapered guide, act on the bevelled end of a pointed piercer and punch a hole in the membrane. This ensures the possibility of the flow of compressed inert gas through the membrane into the working cavity of the pneumatic spring compensator.EFFECT: improving the performance and reliability of the installation, reducing the vibration of underground pumping equipment caused by the presence of gas inclusions in the pumped formation fluid.1 cl, 5 dwg

Description

The invention relates to techniques for oil production, in particular to techniques for raising the produced products of wells, namely, oil and gas emulsions, and for the design of well pumping units.

Known borehole pump installation containing a centrifugal pump with an electric motor installed in the well on a column of lifting pipes, a pneumatic cap for damping pressure pulsations in the pipes and a check valve with an axial throttling channel. The pneumatic cap is located in the cavity of the lifting pipes, and the check valve is installed in its lower part (A.S. USSR No. 918419, class E21B 43/00, 1982).

A disadvantage of the known design is the lack of reliability due to the long time to bring into working condition, which is necessary to separate the gas from the liquid, with a small amount of free gas contained in the liquid.

Also known is a pneumatic piston compensator (Bagramov R.A. Drilling machines and complexes / R.A. Bagramov. - M .: Nedra, 1988. S. 269, copy attached). The pneumatic piston compensator includes a piston dividing the compensator chamber into two parts: a piston cavity and a cavity filled with compressed nitrogen. When pressure fluctuations occur in the hydraulic system, the piston moves: during the pressure increase in the hydraulic system, the liquid of the sub-piston cavity presses on the piston, as a result of which it moves into the cavity filled with compressed gas, and when the pressure decreases, the piston pushes the liquid from the sub-piston cavity into the hydraulic system. Thus, the damping of pressure fluctuations occurs.

The disadvantage of this design is the low reliability of the piston, which is under pressure from the compressed gas during the hoisting operations of the device.

Closest to the invention is a downhole pumping unit containing a pneumatic cap with a piston. An inert gas is contained in the cap under the necessary pressure, which is pumped into the cap before the equipment is lowered into the well (RF Patent No. 2641812, CL ЕВВ 43/00, application form 20.02.2017).

The disadvantage of this installation is the increased value of the loads on the package of Belleville springs and piston for the period of descent of the equipment and the time before the installation starts, which leads to a decrease in reliability.

No technical solutions coinciding with the set of essential features have been identified, which allows us to conclude that the patentability condition is “novelty”.

The aim of the invention is to increase the availability and reliability of the installation, reducing vibration of the underground pumping equipment caused by the presence of gas inclusions in the pumped formation fluid.

A downhole pump installation comprises a submersible electric centrifugal pump with an electric motor installed in a borehole on a tubing string (tubing) and a pneumatic spring compensator located above them to suppress pressure pulsations, the piston of which is spring-loaded from the inside by a packet of serially connected cup springs having such a force characteristic that the force of the packet serially connected disk springs and inert gas pressure on the piston create the resulting restoring force with per area of a given small (quasi-zero) stiffness.

What is new is that according to the invention, a container with a compressed inert gas is installed above said pneumatic spring compensator, comprising a membrane with a pointed piercer provided with a return spring resting against one end of the container body with compressed inert gas and the other against a thrust ring in the body of the pointed piercer, the sharp end of which is directed to the membrane, with the possibility of organizing the movement of scrap discharged into tubing from the day surface of the well, moving in a conical direction yayuschey and acting on the bevelled end of the pointed punch, moving it and punching a hole in the membrane, with the possibility of overflow of pressurized inert gas through the membrane into the working chamber air spring compensator.

The claimed technical solution is illustrated by drawings, where

- in FIG. 1 shows a diagram of a downhole pumping unit;

- in FIG. 2 shows a diagram of the process of falling scrap;

- in FIG. 3 is a diagram of a membrane breakdown process;

- in FIG. 4 shows the process of getting scrap into the trap;

- in FIG. 5 shows the process of interaction of scrap with the guide part of the tank.

The proposed downhole pumping unit (Fig. 1) contains a submersible electric centrifugal pump (ESP) 1, an electric motor 2, a spring-loaded compensator 3 located on the outlet of the submersible ESP 1.

The spring-loaded compensator 3 (Fig. 2) contains a pressure accumulator in the form of a container 4 with compressed inert gas, a working part consisting of a cylinder with a piston 5 attached to a spring-loaded package of Belleville springs 6. In turn, the container 4 with compressed inert gas has a complex a shape in the form of connected conical and cylindrical shells (not shown in FIG.), forming a conical guide for the movement of scrap 7. For the outflow of compressed inert gas from the tank 4, it has a membrane 8 (local view B, Fig. 2). Penetration of the membrane 8 is carried out by a pointed punch 9 with a beveled end. The chamfered end is necessary to bring the pointed punch 9 into motion by interacting with the crowbar 7. A trap 10 is used to accommodate the scrap 7 after punching the membrane 8. The trap 10 and stop 11 also serve to stop the working part of the pneumatic spring compensator 3. After punching the membrane 8, the pointed punch 9 returns to its original position with the help of a return spring 12 (local view B, Fig. 2) resting against one end of the container body 4, the other on the thrust ring (not shown in Fig.) on the body of the pointed Nogo punch 9 (B fragmentary view of FIG. 2).

The working part of the pneumatic spring compensator 3 (Fig. 2) is a cavity with a piston 5 located in it and a spring-loaded packet of Belleville springs 6, and the packet of Belleville springs 6 is made smaller than the diameter of the cylinder in view of the increase in diameter of the packet of Belleville springs 6 during compression. The piston 5 restricts the movement of the disk spring package 6, which abuts in the lower position against the piston travel stop 13 made with holes 14 (section BB, FIG. 2), which eliminates the distortion of the piston 5.

To supply the pumped reservoir fluid, a guide pipe 15 (Fig. 2 and 3) is used, perforated with holes 16, through which pressure is transferred from the pumped reservoir fluid to the working part of the air spring compensator 3. The guide pipe 15 is fixed in the housing 18 of the air spring compensator 3 by using centering knitting needles 17 (section G-D, Fig. 2). A container 4 with compressed inert gas is installed in the housing 18 of the pneumatic spring compensator 3, above its working part, formed by the piston 5 and a spring-loaded package of serially connected cup springs 6 located in the cylinder.

Downhole pumping unit operates as follows. Before the descent of the pumping equipment into the tank 4 is injected compressed inert gas. After lowering the pumping equipment into the well, before starting work in the tubing, scrap 7 is dumped (Fig. 2). Having reached the pneumatic spring compensator 3, the scrap 7 (Fig. 5) is guided along the conical guide - the conical shell of the container 4 with compressed inert gas to the chamfered end of the pointed punch 9. Acting on the pointed punch 9, the scrap 7 sets it in motion, rushing further into the trap 10 (Fig. 3). A pointed punch 9 pierces the membrane 8 in a container 4 with a compressed inert gas, contributing to the flow of compressed inert gas from the tank 4 (Fig. 4, local view B). Compressed inert gas rushes into the sub-piston space of the working part of the pneumatic spring compensator 3 with a cup disk 6.

During the operation of the submersible electric centrifugal pump 1, the reservoir fluid enters the guide pipe 15 at the bottom of the pneumatic spring compensator 3, then rushes to the cylinder and, acting on the piston 5, helps to compress the disk cup springs 6 and inert gas in the under-piston space. In the event of a pressure drop on the discharge of the submersible electric centrifugal pump 1, the piston 5 begins to compress the incoming formation fluid, raising the pressure level in the system. In the case of an increase in the pressure of the produced formation fluid, the pressure of the reservoir fluid is transmitted through the piston 5 to the packet of Belleville springs 6 and compressed inert gas, thereby reducing the pressure of the flow.

Changing the design of the proposed borehole pumping unit so that the compressed inert gas participating in the installation is contained in a container 4 located above the working part of the pneumatic spring compensator 3 before starting work, it creates uniform pressure on the working part of the pneumatic spring compensator 3 as from the side of the pumped formation fluid, and in the sub-piston part.

The ability to receive reservoir fluid into the supra-piston cavity with an increase in its pressure, and its displacement with a decrease, reduces the pressure spread in the tubing.

The introduction of pneumatic spring compensator 3 into the design of a packet of serially connected disk springs 6, which have such a power characteristic that, when this packet of disk springs 6 is connected in parallel with an inert gas pressure force on the piston 5, a resulting restoring force is created with the working section of a given low (quasi-zero) stiffness . This design allows you to reduce pressure fluctuations in the tubing, and therefore, the vibration of the equipment.

The use of a pneumatic spring compensator reduces the negative effects of pressure fluctuations on the discharge of a submersible electric centrifugal pump, prevents the occurrence of vibration loads.

The implementation of the proposed facility provides effective damping of the vibration of the underground pumping equipment caused by the presence of gas inclusions in the reservoir fluid. As a result, the operating efficiency of wells equipped with electric centrifugal pump installations is increased by increasing the overhaul period of their work.

Claims (1)

A downhole pump installation comprising a submersible electric centrifugal pump with an electric motor installed in a borehole on a tubing string and located above them to suppress pressure pulsations, a spring-loaded compensator, the piston of which is spring-loaded from the inside by a packet of successively connected cup springs having such a force characteristic that the force of the stack is connected in series disk springs and inert gas pressure on the piston create the resulting restoring force with working it has a section of a given low quasi-zero stiffness, characterized in that a container with a compressed inert gas is installed above the pneumatic spring compensator, containing a membrane with a pointed puncturer equipped with a return spring, abutting against one end of the container body with compressed inert gas, and the other on the thrust ring in the body of a pointed punch, the sharp end of which is directed to the membrane with the possibility of organizing the movement of scrap when it is dropped into tubing from the surface of the well the movement of the cone, actions on the tapered end of the pointed punch, moving it, punching a hole in the membrane and allowing the compressed inert gas to flow through the membrane into the working cavity of the pneumatic spring compensator.

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