RU2159844C2 - Gear to clean face zone of well - Google Patents

Abstract

FIELD: oil industry. SUBSTANCE: invention is meant to work face zones of wells by method of formation of momentary pressure differential. Gear includes two rows of tubes arranged concentrically, outer and inner, and packer. Cylinder with radial windows is linked to outer row of tubes. It houses spring-loaded piston. Inner row of tubes is fitted with well pump. Hollow rod with radial holes interacting with piston is mounted across intake of pump. Windows are shut off by body of piston in its initial position and space under packer is isolated from inner space of tubes. Space under packer communicates with space of tubes through windows in extreme lower position of piston. EFFECT: multiple action on face zone of well by way of formation of momentary pressure differentials in face, possibility of examination of wells to test efficiency of cleaning operation without replacement of underground equipment. 2 dwg

Description

 The invention relates to the oil industry, specifically to devices for processing bottom-hole zones of wells by the method of creating instant depressions on the bottom-hole formation zone.

 A device is known for treating the bottom-hole zone of a well by an implosion method, comprising a packer, a housing with radial channels, a spring-loaded differential piston with radial holes located in the housing, a cylinder with a two-stage piston installed in it, and a ball valve located between the pistons (AS 721524, E 21 B 43/26).

 This device has the disadvantage that in its design features it cannot ensure the creation of a sharp pressure drop on the bottomhole formation zone.

 As the fluid is pumped out of space A, the pressure drop between spaces A and B grows. When this pressure drop reaches a value sufficient to overcome the pressure in space A transmitted to the piston through the holes, and the spring forces and with a further increase in this pressure drop, the ball will be squeezed from the piston by pressure from below through the central channel in the piston, and the piston will remain in place in the lower initial position due to its own weight and friction forces, and the liquid from space B through the channel in the piston and the bulk in the body flows into space A as it is evacuated from space A, and the necessary sharp pressure drop in the bottomhole zone of the well is not provided.

 It is also known a device for processing the bottom-hole zone of a well by the implosion method, consisting of a housing with radial channels, a lower step piston with an axial channel, an upper spring-loaded piston with an axial channel, a ball valve installed between the pistons, a packer (see.with. 1004624, E 21 B 43/26).

 This device has a disadvantage similar to the disadvantage of the device in a. with. 721524.

 Closest to the invention in technical essence and the achieved effect is a "Device for cleaning the bottom-hole zone of the well", consisting of concentrically placed relative to each other columns of the outer row of pipes and an inner cylinder connected to the outer row of pipes with windows, inside of which is placed spring-loaded from the bottom side a piston with channels, a packer, a hollow stem with a valve connected to the inner row of pipes and interacting with the piston (see AS 540029, E 21 B 24/00).

 The device operates as follows.

 Under the influence of a part of the weight of the empty tubes of the inner row, the hollow rod moves the piston down to the end of the tubes in the upper cylinder cover. In this case, the channels in the piston coincide with the windows in the cylinder, pressure depression occurs and fluid from the well rushes through the windows and the channel, the hollow rod into the free part of the pipes. Then create a second depression.

 To do this, additional pressure is given to the valve from the surface, under the action of which the valve closes and the piston moves down to align the channels with the windows. This creates a second depression and the formation fluid rushes through the channels, windows and openings in the upper cylinder cover into the free cavity of the pipes.

 To repeat the cycle, the liquid in the pipes is replaced with air using a compressor.

This device has significant disadvantages, which are as follows:
firstly, to conduct research on checking the effectiveness of the impact on the formation, it is necessary to change the underground equipment - raise the device and lower the submersible pump, and if necessary, repeat operations on the impact on the formation (according to the results of measurements of the well flow rate) - change the underground equipment again. All this is associated with the expenditure of labor and money;
secondly, in order to achieve a second depression on the formation, it is necessary to have an aggregate on the well with which the necessary pressure is created on the valve and the stem, which also requires additional costs;
thirdly, to repeat the cycle of work on the impact on the reservoir, the fluid in the pipes is replaced by air, which is also associated with additional costs (use of a compressor);
fourthly, the cylinder from the bottom side is muffled and in the case of liquid entering the cylinder cavity under the piston, the latter prevents the piston from moving down, and the device does not work;
fifthly, the device is difficult to manufacture due to the presence of radial and vertical channels and holes in the cylinder cover, thrust rings and valve.

 The purpose of the invention is to simplify the design of the device, increase the reliability of its operation, provide the possibility of multiple repetition of cycles on the impact on the bottomhole formation zone without additional use of equipment (unit for pumping fluid and compressor) and conducting well research to verify the effectiveness of the cycle of work on the formation without changing underground equipment.

 This goal is achieved by the fact that the device for cleaning the bottom-hole zone, consisting of concentrically placed relative to each other outer and inner rows of tubing connected to the end of the outer row of cylinder tubes with radial windows, inside of which is placed a piston spring loaded from the bottom of the bottom, a packer, a hollow rod connected to the inner row of pipes and interacting with a piston pumping in the upper position of the window in the cylinder and opening them in the lowermost position for communication It is improved with the fact that the hollow rod is made with radial holes and placed at the inlet of the downhole pump installed at the end of the inner row of pipes, and a longitudinal channel is made in the cylinder at the lower end.

 The device is shown in the drawing: FIG. 1 - device in the initial position; FIG. 2 - the device is in the working position.

 The proposed device for cleaning the bottom-hole zone of the well consists of an outer row of pipes 1 with a packer 2, a cylinder 3 with radial channels 4, a piston 5, spring-loaded from below by a spring 6. An inner row of pipes 7 with a deep pump 8 is lowered into the outer row of pipes, under which a hollow rod 9 with radial holes 10, interacting with the piston 5. On the hollow rod 9 has a centering lamp 11.

 To limit the stroke of the piston 5 up and down and fix it in the extreme upper and lower position in the cylinder 3, projections 12 and 13 are made. In the cylinder 3, a longitudinal channel 14 is made in the lower end.

 The device operates as follows.

 When lowering the device on the pipes 1 into the well to a predetermined depth, the annular space is sealed using a packer 2.

 In this case, the packer is located above the formation selected for impact directly above the perforation interval, and the device itself is against the formation. Then it lowers the inner row of pipes 7 with a deep pump 8, over which the hollow rod 9 with radial holes 10 and centralizer 11 is placed, to a depth of 2-3 m above the spring-loaded piston 5. The piston 5 is in its highest position under the action of the spring 6 and the channel 4 in the cylinder 3 of the device is blocked by the body of the piston 5. The borehole space is isolated from the internal cavity of the pipes 1 and 7.

 The device is in the starting position.

 Pump 8 pumps liquid from pipes 1. In this case, the annulus (between pipes 1 and 7) is filled with gas (air).

 The fluid is pumped to a level in the annulus providing the necessary differential for the bottomhole zone of the well. After that, pipes 7 are allowed. In this case, the pipe 9 sits on the piston 5 and, overcoming the efforts of the spring 6, moves it down to the stop.

 When the piston 5 is planted on the protrusion 13, the channel 4 opens and communicates the under-packer space of the well with the annulus (between pipes 1 and 7), a sharp pressure drop is created on the formation and fluid from the well through the channel 4 rushes from the formation into the space between the pipes 1 with high speed and 7, and removes mechanical impurities from the bottom of the formation that clog the pores of the formation.

 If necessary, repeat the operation lift the pipe 7 to its original position. In this case, the pipe 9 releases the piston 5 and the latter under the action of the spring 6 returns to its original position. Then, the operation to influence the bottom-hole zone is repeated in the described sequence. After the process of stimulating the formation, the inner row of pipes 7 with the pump 8 remains in the approved (working) position. In this case, the under-packer space of the well is communicated through channel 4 with the annulus. In this position, start the pump 8 in the work and carry out the necessary work to study the well and determine the effectiveness of the event, without re-equipping the well. If the desired efficiency is not achieved, if necessary, the cycle of work on the impact on the bottomhole zone of the well can be repeated in the above sequence as many times as necessary until the effect is achieved. In this case, it is not required to involve additional equipment (unit, compressor, etc.) in this work. At the end of all work, the device is removed from the well, the downhole pump is lowered and the well is put into operation. Further operation can be carried out without removing the device from the well and at any time, if necessary, to influence the bottom-hole zone, which is not provided by other known devices.

 The use of the proposed device for cleaning the bottom-hole zone of the well provides a multiple impact on the bottom-hole zone of the well, makes it possible to conduct a well study and verify the effectiveness of the event, without changing the underground equipment after the operation or a series of operations on the formation, eliminates the need to involve additional equipment (unit) pumping compressor).

Claims (1)

 A device for cleaning the bottom-hole zone, consisting of outer and inner rows of tubing arranged concentrically relative to each other, connected to the end of the outer row of cylinder tubes with radial windows, inside of which there is a piston spring loaded from the bottom side, a packer, a hollow rod connected to the inner a number of pipes and interacting with a piston that overlaps in the extreme upper position of the window in the cylinder and opens them in the extreme lower position for communication with the internal cavity of the external venom pipes, characterized in that the hollow shaft is configured and arranged radial holes for receiving downhole pump mounted on the end of the inner row of tubes and in the cylinder bottom there is formed a longitudinal bore.

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