RU2243368C1 - Method for treatment of well-adjacent bed zone - Google Patents

Abstract

FIELD: mining industry.

SUBSTANCE: method includes forming of periodical pressure pulses in well-adjacent bed zone in form of fading standing wave, above latch of well a high pressure cylinder with piston is mounted. Above said cylinder a low pressure cylinder is placed coaxially, with piston, connected to high pressure cylinder piston. Cylinders from hydraulic multiplier. Periodical pulses of pressure in well-adjacent zone for forming a fading standing wave are formed by impact against surface of well liquid by charge of compressed gas through hydraulic multiplier. For this compressed gas is ed to low pressure cylinder through branch pipe below piston. Pressure of compressed gas feeding is less for vale of relation of square cylinder diameters. Fading standing wave moves along well hollow and form repression-depression pulses. During displacement of liquid along well from well-adjacent bed zone to day surface pressure is dropped.

EFFECT: higher safety, higher efficiency.

1 dwg, 1 ex

Description

The alleged invention relates to mining and can be used to develop and restore the production rate of production wells, which decreased as a result of the mudding of the borehole zone of the formation by asphalt-resin-paraffin formations and solids.

A known method of processing the borehole zone of the formation and a device for its implementation (Agliullin M.N., Kurpanov A.S., Rakhmatullin R.Kh., Abdullin M.M. Patent No. 2123591, Cl. E 21 V 43/25), when which produce simultaneous physical and pulsed depression and repression to stabilize the current values of hydraulic conductivity.

However, for the implementation of the method requires the use of a string of tubing, descent of equipment and cable using a winch, etc.

A known method of processing the bottom-hole zone of the formation (Orlov G.A., Khusainov V.M., Musabirov M.Kh., Pestrikov V.I. Patent No. 2169821, Cl. E 21 B 43/25), when used which is lowered into the well implosion device, pump the processing compound, push it into the reservoir, carry out cleaning by creating multiple implosion exposure.

However, the implementation of the method requires the use of tubing string, packer, implosion device, processing composition, etc.

A known method of cleaning a well from deposits during its operation (Veliev F.G., Kurbanov R.A.-I., Aliev E.N., Patent No. 1700207, Cl. E 21 B 37/00), in which they periodically create negative pressure waves, for which the valves on the flow line are closed and kept in the closed state, then opened.

However, the maximum change in pressure from water hammer when opening the flow line is 1.5 MPa for a split second, which is not enough for the formation of a powerful wave, in addition, it is necessary to use a string of tubing and a pump to provide it with power.

There is a method of development and cleaning of the bottomhole zone of wells by pulse drainage (Nosov P.I., Senochkin P.D., Nurislamov N.B. et al. Patent No. 2159326, Cl. E 21 B 43/25), taken as a prototype, in wherein the formation of a depression of the pressure differential between the borehole zone of the formation and the well cavity is done by pre-pumping fluid into the well, creating periodic pressure pulses in the borehole zone of the formation in the form of a damped standing wave moving along the well cavity, and bleeding off the pressure when the fluid moves about the well from the near-wellbore zone of the formation to the day surface with a sharp opening of the well cavity.

However, the amplitude of a decaying standing wave depends on the fluid pressure in the well cavity.

The objective of the invention is the formation of a decaying standing wave with an amplitude independent of the fluid pressure in the well cavity, the rejection of the use of sophisticated equipment and increased safety.

The problem is solved by the fact that, using a method of processing the borehole zone of the formation, including the formation of a depressive differential pressure between the borehole zone of the formation and the cavity of the well, by creating periodic pressure pulses in the borehole zone of the formation in the form of a damped standing wave moving along the cavity of the well and creating repression-depression pulses, and pressure relief when moving the fluid along the well from the near-wellbore zone of the formation to the surface, the well is equipped with a valve, above it, m Introduce a high-pressure cylinder with a lateral outlet for filling liquid and draining contaminants, and with the piston and above it coaxially - a low-pressure cylinder with nozzles for supplying compressed gas and with a piston connected to the piston of the high-pressure cylinder, forming a hydraulic multiplier, periodic pressure pulses in the near-well zone for the formation of a decaying standing wave, they are formed by hitting the surface of the borehole fluid with a discharge of compressed gas through a hydraulic multiplier by supplying compressed gas to the cylinder low pressure through the nozzle located above the piston under a pressure smaller by the ratio of the square of the diameters of the cylinders, the pressure relief in the well is formed by creating a vacuum through the hydraulic multiplier by supplying compressed gas to the low-pressure cylinder through the nozzle located under the piston under a pressure smaller by ratios of squares of cylinder diameters.

This method allows you to restore the hydraulic connection between the well cavity and the formation without stopping the well for overhaul, the use of equipment for lowering and lifting the downhole pipes, as well as electricity.

An example of a device for implementing the proposed method is illustrated in the drawing, in which: 1 - well; 2 - valve; 3 - high pressure cylinder; 4 - the piston of the high pressure cylinder; 5 - low pressure cylinder; 6 - the piston of the low pressure cylinder; 7 - lateral branch; 8 - over-piston nozzle for supplying compressed gas; 9 - piston pipe for supplying compressed gas.

On the well 1 install the valve 2 to ensure the safety of work. Above the valve 2, a high pressure cylinder 3 is mounted with a piston 4, and a low pressure cylinder 5 with a piston 6 is mounted coaxially above. The pistons of both cylinders are interconnected. The high-pressure cylinder 3 has a lateral branch 7, the low-pressure cylinder has a supra-piston 8 and a sub-piston 9 nozzles for supplying compressed gas.

The method is implemented as follows. Liquid is poured into the well 1 through the nozzle 7 to the level of the piston 5. Compressed gas is supplied through the nozzle 8, under the pressure of which the piston 6 moves down, the piston 4 connected to the piston 6 also moves down and has an impact on the surface of the well fluid. A pressure wave is formed, which moves along the well cavity from the wellhead to the bottom and back, creating impacts, including in the near-wellbore zone of the formation. Repression and depression impulses make it possible to disrupt adsorption deposits on the walls of pore channels.

Cylinder 5 has a diameter larger than cylinder 3; therefore, in order to obtain a pressure in cylinder 3 sufficient for repression and depression pulses of well fluid movement, a pressure lower than the ratio of the squares of cylinder diameters is applied to cylinder 5. Under the pressure of the compressed gas, the pistons 4 and 6 are moved to the lower position.

When an impact is made, the lateral branch 7 is closed to concentrate energy in the direction of the bottom hole.

After processing the near-wellbore zone of the formation with periodic pressure pulses of a decaying standing wave, compressed gas is discharged from the over-piston part of cylinder 5. Through the pipe 9, compressed gas is pumped into the under-piston part of the low-pressure cylinder 5, pistons 4 and 6 are moved upward, a vacuum is created in the well, which contributes to the active removal of contaminants from the borehole zone of the formation into the cavity of the well. Heavy contaminants descend into the sump, light contaminants float to the surface and are removed from the well cavity through branch 7.

The process is repeated until the required degree of purification of the borehole zone of the formation is achieved.

To influence the borehole zone of the formation, a combination of hydraulic shock is used, which helps to separate the adsorption deposits from the walls of the pore channels and create a vacuum for depressive differential pressure on the perforation of the well and the removal of contaminants into the well cavity.

In the process of processing the near-wellbore zone of the formation, the movement of the pistons up and down is actively used, and the movement down should be carried out with maximum acceleration.

When cleaning the near-wellbore zone of the formation, there is no need to use a pumping unit for pumping fluid and creating high pressure in the well, as well as using a high-pressure compressor. The use of low pressure in the production and transmission of compressed gas increases the safety of work.

When using compressed air, there is no danger of ignition when it comes in contact with the gas released by the well fluid, since they are separated by two pistons.

The described method is used both on wells equipped with a tubing string and without it and is used without stopping the well for overhaul, as well as in the process of overhaul replacing the swabbing operation.

Well fluid may contain chemicals for more efficient cleaning. The method can be applied in conjunction with other types of processing of the borehole zone of the formation: acid, thermal, vibrational, acoustic, etc.

Claims (1)

A method of treating a borehole zone of a formation, including forming a depression of the pressure differential between the borehole zone of the formation and the well cavity by creating periodic pressure pulses in the borehole zone of the formation in the form of a damped standing wave moving along the well cavity and creating repression-depression impulses, and relieving pressure when the fluid moves down the well from the borehole zone of the formation to the surface, characterized in that the well is equipped with a valve, mounted above it high pressure reservoir with lateral outlet for filling liquid and discharge of contaminants, and with the piston, and above it coaxially - a low pressure cylinder with nozzles for supplying compressed gas and with a piston connected to the piston of the high pressure cylinder, forming a hydraulic multiplier, periodic pressure pulses in downhole zone for the formation of a decaying standing wave is formed by hitting the surface of the borehole fluid with a discharge of compressed gas through a hydraulic multiplier by supplying compressed gas to a low-pressure cylinder through a nozzle located above the piston under a pressure smaller by the ratio of the square of the diameters of the cylinders, the pressure relief in the well is formed by creating a vacuum through a hydraulic multiplier by supplying compressed gas to the low pressure cylinder through the nozzle located under the piston under a pressure smaller by the value of the ratio of squares bore diameters.