RU2217584C1 - Method of well treatment in formation - Google Patents

Abstract

FIELD: mining industry, completion and recovery of discharge of producing wells that decline due to mud grouting of critical area of formation with asphalt-resin-paraffin formations and contamination. SUBSTANCE: well is fitted with valve. High-pressure cylinder with side branch for drainage of well fluid and piston is installed above valve. Low-pressure cylinder with branch pipe to feed compressed gas and piston linked to piston of high-pressure cylinder is placed uniaxially above it to form hydraulic booster. Preliminary pumping of fluid into well is conducted to create pressure sufficient to move fluid to day surface with opening of well space. Periodic pulses of pressure in critical area of formation to create damped standing wave are formed by hammer on surface of well fluid with discharge of compressed gas through hydraulic booster. Compressed gas is fed under pressure into low-pressure cylinder through feeding branch pipe. Pressure of compressed gas is less by value of relation of squares of diameters of cylinders with overlapping of hole of side branch by piston of high-pressure cylinder and with its opening with release of compressed gas from low-pressure cylinder. EFFECT: improved reliability of formation of damped standing wave with amplitude independent of pressure of fluid in space of well, simplified design and increased functional safety of equipment employed to realize this method. 1 dwg

Description

The present invention relates to mining and can be used to develop and restore the production rate of wells, decreased as a result of mudding of the borehole zone of the formation with 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, class E 21 B 43/25), when which produce simultaneous physical and pulsed depression and repression to stabilize the current values of hydraulic conductivity.

However, to implement 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, class 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, class E 21 B 37/00), in which they periodically create at the wellhead, 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 fraction of a second, which is not enough for the formation of a powerful wave, in addition, it is necessary to use a tubing string and a pump with its power supply.

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, class E 21 B 43/25), taken as a prototype, including the formation of a depression of the pressure differential between the borehole zone of the formation and the cavity of the well, which is carried out by preliminary injection of fluid into the well, the creation of 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 release of pressure when moving fluid along 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 in that, using a method of processing the borehole zone of the formation, including the formation of a depressurized pressure differential between the borehole zone of the formation and the cavity of the well 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 cavity of the well and creating repression and depression impulses, and pressure release when moving the fluid along the well from the borehole zone of the formation to the day surface In case of a sharp opening of the well cavity, the well is equipped with a valve; above it, a high pressure cylinder with lateral outlet is installed to drain the well fluid and with a piston and coaxially above it - a low pressure cylinder with a nozzle for supplying compressed gas and with a piston connected to the piston of the high cylinder pressure, forming a hydraulic multiplier, the preliminary injection of fluid into the well is carried out to create a pressure sufficient to move the fluid to the surface when opening the cavity of the well, iodic pressure pulses in the near-wellbore zone to form a decaying standing wave are generated by hitting the surface of the wellbore fluid with a compressed gas discharge through a hydraulic multiplier by supplying compressed gas to the low-pressure cylinder through a pressure supply pipe less by the ratio of the square of cylinder diameters, with the piston overlapping the high-pressure cylinder openings of a lateral branch and its opening at release of compressed gas from the low-pressure cylinder.

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 - pipe annulus; 3 - valve; 4 - high pressure cylinder; 5 - piston of a high pressure cylinder; 6 - low pressure cylinder; 7 - the piston of the low pressure cylinder; 8 - lateral tap to drain the well fluid; 9 - pipe for supplying compressed gas.

Well 1 has a pipe annulus 2. A valve 3 is installed on well 1 to ensure the safety of work. Above the valve 3, a high pressure cylinder 4 is mounted with a piston 5, a low pressure cylinder 6 is mounted coaxially above the piston 7. The pistons of both cylinders are interconnected. The high-pressure cylinder 4 has a lateral outlet 8 for draining the well fluid, the low-pressure cylinder has a pipe for supplying compressed gas 9.

The method is implemented as follows. Liquid is pumped into the well 1 through the annulus 2 nozzle and a pressure is created sufficient to move the fluid to the day surface when opening the well cavity. Under the influence of excess pressure, the fluid penetrates into the borehole zone of the reservoir.

To carry out an impact on the surface of the borehole fluid through the pipe 9 serves compressed gas, under the pressure of which the piston 7 moves down. A piston 5 connected to the piston 7 also moves downward and exerts pressure 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 6 has a diameter larger than cylinder 4; therefore, in order to obtain a pressure in cylinder 4 that is sufficient for repression and depression pulses of well fluid movement, a pressure lower than the ratio of the square of the cylinder diameters is applied to cylinder 6.

When performing a stroke, the piston 5 lowers and closes the tap hole to drain the well fluid 8 for energy concentration in the direction of the bottomhole zone of the well. After the impact, compressed gas is discharged from cylinder 6, pistons 5 and 7 are raised under pressure from the wellbore and open the drain hole for discharge 8. Wellbore fluid is poured to depressively remove contaminants from the near-wellbore zone of the formation. Contaminants are actively carried out from the near-wellbore zone of the formation into the cavity of the well and then through the tap to drain the well fluid 8 to the surface.

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

The pressure in the well is necessary only for moving the fluid to the day surface and can be small in magnitude, therefore, it is possible to increase the amplitude of the decaying standing wave without the risk of damage to the tubing or casing, violation of the integrity of the cement stone. There is no need to use a high-pressure pump unit (for example, ЦА-320).

No need for a high pressure compressor. It is possible to use, for example, an additionally installed automobile compressor used in the brake systems of KAMAZ and URAL, creating a pressure of 10-12 atm at a flow rate of 373 l / min and equipped with a receiver.

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.

When processing an injection well, the pressure for outflow of fluid from the well is created by pumping fluid designed to maintain reservoir pressure. When processing a producing well, the pump-pump rod is removed, the pressure for pouring liquid from the well is created by pumping liquid into the annulus.

The described method is applicable both to wells equipped with a tubing string, and without it.

The described method can be used without stopping the well for overhaul, as well as in the process of overhaul, replacing it with a swab operation.

Well fluid may contain chemicals for more efficient cleaning. The method can be applied in conjunction with other types of bottom-hole treatment: acidic, thermal, vibrational, acoustic, etc.

Claims (1)

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 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 cavity of the well and creating repression and depression impulses , and pressure relief when moving the fluid along the well from the near-wellbore zone of the formation to the day surface with a sharp opening of the cavity with important, characterized in that the well is equipped with a valve, above it a high pressure cylinder is installed with a lateral outlet for draining the well fluid, and with the piston, and coaxially above it, a low pressure cylinder with a nozzle for supplying compressed gas and with a piston connected to the cylinder piston high pressure, forming a hydraulic multiplier, the preliminary injection of fluid into the well is carried out to create a pressure sufficient to move the fluid to the surface when opening the cavity of the well, periodically pressure pulses in the borehole zone to form a decaying standing wave are generated by hitting the surface of the wellbore with a compressed gas discharge through a hydraulic multiplier by supplying compressed gas to a low pressure cylinder through a pressure supply pipe less by the ratio of the square of the cylinder diameters, with the piston blocking the opening of the high pressure cylinder lateral outlet and its opening when releasing compressed gas from a low pressure cylinder.

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