RU2412335C1 - Oil well pumping unit with packer for extracting oil under abnormal conditions - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: pumping unit consists of pump and one or several packers lowered successively into well on flow string. The unit is additionally equipped with a three-position back valve installed directly above the pump. The valve consists of a case, a ball, and a hollow rod inside the case. An upper part of the rod is made in form of a seat for the ball, while under the seat there are made through radial channels on it. Further, the valve consists of a bushing above the ball, of a movable hollow rod positioned on external generatrix of the hollow rod coaxially to it and designed to shut off and open radial channels of the hollow rod. Also, the movable hollow rod is spring loaded. When the unit includes at least two packers, then there is installed a compensation valve of mechanical action between the packers in the flow string. The column for overflow of gas is positioned concentrically in the flow string; bottom of the column is connected with a unit of cross flow; or the flow string is equipped with a device for separation and injection. The unit is also furnished with a device for rigid or sliding pressure tight connection and disconnection of parts of the flow string. An upper part of the column for gas overflow is coupled with a wellhead production tree; in its cavity there are installed a pressure control or gas choke chamber.

EFFECT: raised efficiency of pumping unit for extraction of oil in wells at disorder of production well.

4 cl, 5 dwg

Description

The invention relates to the oil and gas industry and can be used for the production of liquid hydrocarbons, especially in wells complicated by violations of the production string or revealing several productive horizons.

A well-known Sharifov pumping unit for well operation (options) (patent RU No. 2300668, F04D 13/10, 06/10/2006), in which a protective pipe for a pump with a sand filter or packers with or without cable entry is used. The known installation is not effective enough due to downtime during the repair of a clogged pump.

The closest to the invention in technical essence and the achieved result is a downhole packer installation with a pump (options) (patent RU No. 2331758, ЕВВ 43/00, 03/20/2008), which includes a pump and one lowered into a well on a string of pipes of constant or variable diameter or several packers, with or without cable entry, and which improves the well’s efficiency by separating the insulated interval from the production facility and the packer from the pump with simultaneous bypass of the medium. The known installation is not effective enough due to forced downtime during the repair of a clogged pump, since there is no possibility of cleaning the pump cavity from salt deposition or sedimentation of mechanical impurities. In addition, the lifting of a multi-packer pumping unit is difficult due to the pressure drop above and below the packer sealing zone: the values of additional loads may exceed the limits of permissible loads on the pipe string and equipment.

The solved problem and the technical result of the invention is to increase the efficiency of a downhole pumping unit for oil production in complicated conditions of a multilayer field and to increase oil production from wells with violation of the tightness of production casing by increasing the overhaul period by periodically cleaning the pump cavity, as well as by increasing safety and reduce complications during hoisting operations with packer installations. This, in turn, will increase the efficiency of use of both pumping equipment and development facilities, and will lead to an increase in oil production.

The problem is solved in that the downhole pumping unit for oil production in difficult conditions, including a pump and one or more packers, lowered into the well sequentially on a pipe string, is characterized in that it is equipped with a three-position check valve additionally installed directly above the pump, consisting of a body, a ball hollow rod inside the housing, the upper part of the rod is made in the form of a saddle for the ball, and under the saddle there are through radial channels, bushings above the ball, a movable hollow piston, p the movable hollow piston is spring-loaded, and if the installation includes at least two packers, then an equalizing mechanical action valve is installed between them in the pipe string.

The installation is equipped with devices for rigid or sliding tight connection and separation of parts of the pipe string.

A smaller diameter column is concentrically placed in the pipe string, the bottom of which is connected to a cross-section unit for gas bypass, as well as for supplying chemical reagents to the pump intake and in the bottomhole zone or pipe string is equipped with a device for separation and injection, for example, a jet pump.

In cases of execution of pumping units with a concentric pipe string, its upper part is connected with wellhead fountain fittings, in the cavity of which a pressure regulator or choke chamber for gas is installed.

Figure 1-3 is a schematic representation of the inventive installation.

Figure 4 schematically shows a three-position check valve in three states: when the pump unit is operating (left), when the pump unit is stopped (in the center), and when liquids of different composition, properties and purpose are pumped through it (right).

Figure 5 schematically shows an equalizing valve of mechanical action in two states: closed during operation of the pumping unit (left), open when lifting the pumping unit with a multi-packer arrangement (right).

Figure 1-5 marked:

1. Production column.

2. A column of pipes.

3. Place of leakage of the production string or perforation interval.

4. A packer with a cable bypass assembly through itself.

5. Additional channel.

6. The pump.

7. Three-position check valve (KOT).

8. Device for the separation and injection of liquid and gas.

9. Device for rigid or sliding tight connection and separation of pipe string parts.

10. Wellhead fountain fittings with pressure regulator or choke chamber for gas.

11. Productive layer.

12. The node cross-section.

13. A column of pipes of smaller diameter.

14. The second packer.

15. Valve equalizing mechanical action (KUM).

16. The housing of the cat.

17. Hollow stock CAT.

18. The saddle.

19. Radial channels of KOT.

20. Ball.

21. The sleeve.

22. Spring CAT.

23. Movable hollow piston KOT.

24. The KUM building.

25. Radial channels KUM.

26. Hollow stock KUM.

27. Spring KUM.

A downhole pump installation with a packer for oil production in difficult conditions contains: a pipe string 2, a packer with a cable bypass assembly 4 and, possibly, with additional channels 5, pump 6, a three-position check valve (CAT) 7. Additionally, the installation may contain: a device for rigid or sliding hermetic connection and separation of the parts of the pipe string 9, a device for separating and injecting liquid and gas 8, for example a jet pump, or a concentrically placed pipe string of a smaller diameter 13 with an intersection th section 12 for bypassing the gas to the surface, and simultaneously, if necessary, supply of chemicals to the pump suction or bottomhole zone. If the installation contains a second packer 14, then it is equipped with a balancing valve mechanical action (KUM) 15.

The three-position check valve (Fig. 4) consists of a KOT 16 body, a KOT 17 hollow stem with a seat 18 and KOT 19 radial channels, a ball 20, a sleeve 21, KOT 22 springs with adjustable compression force, a movable hollow piston 23. The piston 23 is located on the external generatrix of the hollow rod KOT 17 coaxially with it. The piston 23 is spring-loaded with a KOT 22 spring located between the housing 16 and the hollow stem 17. The spring 22 is bounded on one side by a housing protrusion and, on the other hand, by a movable piston 23 that overlaps or opens the radial channels 19 of the hollow stem 17. The sleeve 21 above the ball 20 is designed to hold ball from removal from the working area. The sleeve can be made, for example, in the form of a collet from the side of the ball with an inner collar on the petals of the collet to hold the ball 20 with a flow of fluid.

The equalizing valve of mechanical action (Fig. 5) consists of the KUM 24 housing, the KUM 25 radial channels, the KUM 26 hollow stem, the KUM 27 spring. The KUM 27 spring is located in the KUM 24 housing and fixes the hollow stem 26 in its highest position, and to a certain lifting force, it prevents the movement of the housing KUM 24 relative to the hollow stem KUM 26. This movement is structurally limited by the protrusions and collars on the housing 24 and the hollow stem 26.

Downhole pumping unit operates as follows.

For oil production from a well with a leak in production casing 1 above the reservoir 11, the pump installation is assembled in the following sequence: mount pump 6 (electric centrifugal or another driven by a submersible electric motor) on pipe string 2, through a predetermined number of pipes, install a three-position check valve 7, packer with a cable bypass assembly through itself 4 and additional channels 5, an additional device for rigid or sliding tight connection and separation of the pipe string 9. C skayut pumping unit to a depth in a pipe string. In a known manner, depending on the design of the packer (mechanical, hydraulic or combined), a packer 4 is installed. A device for separating and injecting liquid and gas 8 can be installed under the packer 4. Additional channels 5 of the packer 4 can be used to divert gas from the sub-packer zone to overpacker (shown in figure 1 with a hollow arrow from the bottom up). An additional device is installed above the packer for tight or sliding tight connection and separation of the pipe string parts 9. If there are large volumes of dissolved gas in the formation fluid, instead of the device for separating and injecting the liquid and gas 8, the pipe string of smaller diameter 13 is concentrically lowered to the tight pipe 13 connections with a cross-sectional assembly 12. Assemble wellhead fountain fittings 10 and install a pressure regulator or choke chamber in a cavity communicating with the column cavity pipes 13. Connect fountain fittings 10 to the oil and gas gathering network. The downhole installation is launched.

When the pump 6 is monitored for the performance of the pumping unit. In the event of a decrease in the productivity of the pump installation or an increase in current loads in the drive (due to clogging or buildup of salt crust on the working bodies of pump 6), the pump installation is stopped. In this case, the ball 20 of the three-position check valve 7 (Fig. 4) is lowered onto the seat 18 of the hollow stem of the KOT 17 and blocks the flow of fluid in the opposite direction into the cavity of the pump 6, thus performing the function of the check valve. The set design differential pressure in the valve 7 above and below the ball 20, caused by the pressure difference under the packer 4 at the level of the valve 7 and the pressure of the liquid column in the pipe string 2 above the valve 7, is held by the KOT 23 movable piston and the KOT 22 spring with an adjustable compression force.

A special fluid is pumped, for example, to remove the salt crust on the working bodies of the pump, by the pump unit from the surface into the cavity of the pipe string 2. When the calculated value of pressure above valve 7 is reached, the KOT 23 movable piston overcomes the force of the KOT 22 spring, drops down and opens the KOT radial channels 19 of the hollow stem of KOT 17. A message is created of the over- and subvalvular space, a special liquid enters the pump cavity 6 and cleans the surface of the pump parts from various deposits 6. After processing the pump cavity 6 a special fluid relieves excess pressure. The movable piston KOT 23 under the action of the spring of KOT 22 with an adjustable compression force rises up, blocks the radial channels of KOT 19 of the hollow stem of KOT 17, and valve 7 returns to the initial state of the non-return valve. The valve 7 holds the column of liquid above itself and facilitates the start-up of the pump 6. The pump installation is put into operation. Also, when a downhole pump unit is equipped with a string of pipes of a smaller diameter 13, various reagents can be supplied to the pump intake and in the bottomhole zone of the well during the operation of the pump unit to improve the working conditions of the pump unit, including changes associated with phase states liquid and gas. If necessary, cleaning and treatment cycles are repeated.

The lifting of the pump unit is carried out in the usual way. In cases of complications during the lifting of the pumping unit associated with the pressure difference above and below the packer, which leads to additional loads during disruption and lifting, the upper part of the pipe string is disconnected from the packer by an additional device for rigid or sliding tight connection and separation of the pipe string parts 9 After pressure equalization and washing of the packer head, again the pipe string is connected to the packer and the installation is lifted in the usual way (Fig. 1).

In the case when the downhole pump installation includes a concentrically arranged pipe string of smaller diameter 13 (FIGS. 2, 3), the pipe string 13 is initially removed, after lifting which the pressure in the pipe cavity above the packer and in the annular space below the packer is equalized. If, when pulling the pipe string, the pump unit with the packer goes up without complications, then it is lifted in the usual way; if lifting is complicated, then work is carried out to disconnect the upper part of the pipe string from the packer by a device for rigid or sliding tight connection and to disconnect the parts of the column 9.

In cases where several packers are used in the pump installation (Fig. 3), the pipe string of smaller diameter 13 is initially removed, equalizing the pressure in the pipe cavity above the upper packer and in the annulus below the lower packer. Lifting a pump unit with two or more packer assemblies is always difficult due to the resulting pressure drop above and below the packer sealing zone. The magnitude of the additional loads that occur when the pressure created by the liquid column on the upper packer exceeds the pressure acting on the lower packer, as well as the pressure in the space between the packers, may exceed the allowable loads on the pipe string and equipment.

When tensioning the pipe string 2 (Fig. 3) with the movement of the upper packer 14, the mechanical balancing valve 15 opens (Fig. 5) due to the fact that the housing of the KUM 24 is rigidly connected through a threaded connection to the upper packer 14, and the hollow rod 26 is connected to the lower packer 4. The lower packer 4 is stationary at this moment (more force is needed to move it) and the KUM 24 body, overcoming the KUM 27 spring force, moves relative to the hollow KUM 26 rod and opens the KUM 25 radial channels. The pressure is balanced in the cavity bounded P ceramics, as well as above and below the packer spaces. Then, without additional loads on the equipment and without the risk of breakage in a known manner, the well pump unit is lifted.

Thus, the inventive downhole pumping unit is more efficient by increasing the overhaul period by periodic cleaning and reducing the risk of breakdown of the pumping unit, including when it is lifted. This, in turn, will increase the efficiency of using both pumping equipment and development facilities, which will certainly lead to additional oil production while lowering operating costs.

Claims (4)

1. A downhole pumping unit for oil production in difficult conditions, including a pump and one or more packers lowered into a well sequentially on a pipe string, characterized in that it is equipped with an additional three-way check valve directly installed above the pump, consisting of a housing, a ball, and a hollow rod inside casing, the upper part of the rod is made in the form of a saddle for a ball, and under the saddle it has through radial channels, bushings above the ball, a movable hollow piston located on the outer forming the hollow rod coaxially with it and with the ability to block and open the radial channels of the hollow rod, the movable hollow piston is spring-loaded, and if the installation includes at least two packers, then a balancing valve of mechanical action is installed between them in the pipe string. 2. Installation according to claim 1, characterized in that it is equipped with devices for rigid or sliding tight connection and separation of the pipe string parts. 3. Installation according to claim 1, characterized in that a concentric pipe string of smaller diameter is placed in the pipe string, the bottom of which is connected to a cross-section unit, or the pipe string is equipped with a separation and injection device. 4. Installation according to claim 3, characterized in that the upper part of the pipe string of smaller diameter is connected to the wellhead fountain fittings and a pressure regulator or choke for gas is installed in its cavity.

Images