RU2451159C1 - Well cleaning method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: during implementation of the method the following is performed: well is separated above perforation interval of productive formation by packer; space under packer is connected to wellhead by pipe string; space of pipe string above packer is separated by spring-loaded valve; space of pipe string above spring-loaded valve is connected to intertube space of well; pipe string above place of connection with intertube space is separated from valve by plunger; fluid is extracted from space of pipe string above plunger with valve and from intertube space until current pressure in well is reached; pressure in pipe string from wellhead is increased; spring-loaded valve is opened and space under packer is connected to intertube space.

EFFECT: improving the cleaning quality.

1 dwg

Description

The invention relates to the oil industry and may find application in the development and restoration of production wells, in particular, for the intensification of inflows of reservoir fluids.

A known method of influencing a reservoir and a device for its implementation, in which they create depression from two sources with a delay in the response time of the second source. When the first source of depression is triggered, the creation of repression at the bottom of the well is organized. When the second source of depression is triggered, repression is organized in the tubing string with the direction of impact to the wellhead. The device includes a pump housing in the form of two connected cylinders, an upper larger diameter and a lower smaller diameter with holes in the upper part and with a shut-off valve and a perforated nozzle with a plugged end in the lower part, and a two-stage plunger consisting of a larger upper plunger with discharge valves and lower smaller diameter with muffled ends. The plungers are interconnected by means of an adapter (RF Patent No. 2188310, publ. 08.27.2002).

A disadvantage of the known technical solution is that the plunger of the pump is significantly higher than the bottom zone, which contributes to the attenuation of the shock wave upon reaching the perforation zone. In addition, impulses from hydroshocks through a rigid metal pump rod are transmitted to the head of the balancer of the rocking machine, which can cause its breakdown.

Closest to the proposed invention in technical essence is a method of developing an oil well, including lowering a casing with a filter into the well, cementing the well, destroying the hollow plugs, cleaning the bottom-hole formation zone using tubing, launching the deep well pump and putting the well into operation. The filter is equipped with hollow plugs with a viscoplastic substance protruding beyond the housing. The plugs are destroyed by lowering the cutting funnel, which is part of one of the parts of the device to create depression on the formation. It includes a packer, housing, ball valve, perforated nozzle. The device is lowered onto the tubing string and used to clean the bottomhole formation zone. To do this, after destruction by the cutting funnel, the ends of the hollow plugs are lowered to the bottom of the well. Then produce disconnection of the reservoir from the overlying part of the well. Create a depression on the reservoir by communicating the zone of the well opposite the reservoir with the interior of the tubing string under atmospheric pressure. After that, the aforementioned part of the device for creating depression on the formation, including a packer, a housing, a ball valve, a perforated pipe with a cutting funnel, is left in the well. Another part of the device for creating depression on the formation, including the rod, spring and sleeve, is raised to the surface and proceed to the descent of the deep pump. Achieving the conservation of reservoir properties of the reservoir, saving time and material resources (RF Patent No. 2199658, publ. 02.27.2003 - prototype).

The disadvantage of this method is its one-time use for cleaning the well, in which high-quality cleaning of the near-wellbore zone may not be achieved.

The proposed invention solves the problem of increasing the time of depressive effects, the possibility of cyclically creating depression, reusability of depression.

The problem is solved in that the method of cleaning the well, including disengaging the well above the perforation interval of the reservoir with a packer, communicating the sub-packer space of the pipe string with the wellhead, separating the space of the pipe string above the packer by a spring-loaded valve, differs in that it additionally performs the message of the space of the pipe string above the spring-loaded valve with the annular space of the well, uncoupling of the pipe string above the place of communication with the annular space with a plunger with a valve, fluid withdrawal from the space of the pipe string above the plunger with the valve and from the annular space to establish the current pressure in the well, increasing the pressure in the pipe string from the wellhead, transferring pressure to the spring-loaded valve, opening the spring-loaded valve and communicating the sub-packer space with the annular space.

SUMMARY OF THE INVENTION

Cleaning the well, perforations and near-wellbore area is an urgent task, because Despite the large number of existing technical solutions, a method of a controlled, multiple exposure that has led to high-quality cleaning of the near-wellbore zone has not yet been developed. The proposed invention solves the problem of increasing the time of depressive effects, the possibility of cyclically creating depression, reusability of depression, the regulation of exposure in magnitude. The problem is solved as follows.

In the well, the assembly shown in FIG. 1 is assembled.

The device consists of a cylindrical body (cylinder) 1, on which, on the one hand, with the help of a sleeve 2, the body of the relief valve 3 with a pin 4 is screwed on, and on the other hand, with the help of a coupling 5, a perforated pipe 6. On the perforated pipe 6 with a sleeve 7 wrap the packer 8 with the shank 9. Inside the cylinder 1, there is a plunger 10 with a valve 11, which is mounted on the plunger 10 by a holder 12. A rod 13 is screwed onto the holder 12. A valve device 14 is installed in the perforated pipe 6, consisting of a housing 15, a saddle on it 16, a poppet valve 17 with a stem 18, springs 19 and a plate-holder 20. The installation is lowered into the well 21 on the string of tubing 22 and "put" on the packer 8 in the perforation zone of the well.

Setting the packer 8 perform the isolation of the well over the interval of perforation of the reservoir. The tubing string 22 communicates the under-packer space with the wellhead. The valve device 14 produce the separation of the space of the pipe string 22 above the packer 8 by a spring-loaded valve. The perforated pipe 6 performs the communication of the space of the pipe string 22 above the spring-loaded valve 14 with the annular space of the well 21. With the plunger 10 and the valve 11, the pipe string 22 is disconnected above the place of communication with the annular space. The pressure is transmitted to the spring-loaded valve by means of a stem 13 and a stem 18.

The device operates as follows.

At balanced fluid pressures in the string of tubing 22 and well 21, the valve device 14 is already closed by means of springs 19 and fluid flow from the formation to the upper zone above the packer 8 is excluded. When fluid is taken from the string of tubing 22 (using a pump and other devices) valve 11 opens and fluid from the annular space of the well 21, passing through the perforated pipe 6, holder 12, valve 11, plunger 10 and the body of the relief valve 3, enters the tubing string 22. By measures lowering the liquid level in the well 21 increases the pressure difference above the packer and for the packer zones, which, in turn, strongly presses the poppet valve 17 against the valve seat 16, i.e., installation is self-sealing.

After reaching the specified pressure difference above the packer and under the packer zones, the selection of liquid in the tubing string 22 is stopped. When this valve 11 is closed, eliminating the flow of fluid from the string of tubing 22 back into the cavity of the well 21. When a certain pressure is applied to the cavity of the string of tubing 22, the plunger 10 starts to move down and, resting against the stem 13 of the stem 18 of the poppet valve 17 creates a force, trying to open the poppet valve 17. When this force is superior to the total force of the springs 19 and the pressure force in the cavity of the liner 9, the poppet valve 17 sharply opens and fluid from the formation through the liner 9, valve arrangement Property 14 and the perforated nozzle 6 rushes into the cavity of the well 21. The higher the pressure difference above the packer and below the packer zones before the poppet valve was actuated, the higher the speed, flow rate and flow time of the formation fluid. Thus, by changing the pressure difference during processing, it is possible to adjust the force of impact on the reservoir.

By creating pulsating pressure fluctuations of different frequencies in the cavity of the tubing string 22 and thereby opening the valve device 14 according to these frequencies, the installation allows the formation to be processed by the resonance method in areas remote from the well.

After processing, the installation is unpacked, the drain hole is created by knocking down the pin 4 to drain the liquid from the cavity of the tubing string 22 and the installation is lifted to the surface.

When using the proposed device for cleaning oil wells, a high efficiency of cleaning the near-wellbore zone without sand development was noted, after cleaning, the flow rate of wells increases 2-4 times.

The application of the proposed device will allow to solve the problem of reducing sand during exposure, regulating the magnitude of the depressive effect and effecting as necessary.

Claims (1)

A method of cleaning a well, including disconnecting a well above a perforation interval of a reservoir by a packer, communicating a sub-packer space of a pipe string with a wellhead, separating a space of a pipe string above a packer by a spring-loaded valve, characterized in that it further communicates the space of the pipe string above the spring-loaded valve with the annular space of the well, uncoupling of the pipe string above the place of communication with the annular space by a plunger with a valve, fluid withdrawal from the column space s plunger pipe above the valve and from the annulus to establish the current pressure in the wellbore, increasing the pressure in the pipe string from the wellhead, transmitting pressure to the spring-loaded valve, the spring-loaded valve opening and with a message space packer annulus.

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