RU2241828C2 - Method for treatment of well-adjacent bed zone - Google Patents

Abstract

FIELD: mining industry.

SUBSTANCE: method includes forming depression pressure change between well-adjacent bed zone and hollow of well by negative pressure wave and forming periodical pressure impulses in well-adjacent bed zone in form of fading standing wave moving along well hollow. For this, cylinders coaxial to compressed gas inlet branch pipe are used, also having side outlet and interconnected pistons. Also used is low pressure cylinder forming a hydraulic multiplier, mounted above high-pressure cylinder mounted above well latch. Negative pressure wave is formed by discharging well fluid above the surface due to feeding compressed gas through branch pipe of its inlet into low pressure cylinder at pressure, less for value of relation of square cylinder diameters.

EFFECT: higher efficiency.

1 dwg

Description

The invention relates to mining and can be used to develop and restore the production rate of production wells, decreased as a result of mudding of the borehole zone of the formation 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 NB and others. Patent No. 2159326, Cl. E 21 B 43/25), in which the formation of a depression the pressure between the borehole zone of the formation and the cavity of the well is carried out 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 bleeding off the pressure when moving the fluid through the well from the well Ina formation zone to the surface at a sharp opening borehole cavity.

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

A device is known for impulse action on the bottomhole zone of a well (Kuznetsov Yu.A., Klevtsur A.P. Patent No. 1637417, CL. E 21 B 43/25), adopted as a prototype, comprising a hollow body with radial holes, movably placed in the body a rod with pistons and a high-pressure line for supplying gas to the body cavity, and equipped with a distribution valve and lock.

However, the amplitude of the received pulses for influencing the bottomhole zone of the well depends on the pressure in the gas line.

The objective of the invention is the formation of a decaying standing wave of sufficient power, regardless of the pressure in the cavity of the well and in the gas main, improving safety and eliminating the compaction of asphalt-resin-paraffin deposits in the pore channels of the borehole zone of the formation under the influence of impacts.

The problem is solved in that, using the 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 with a negative pressure wave and the creation of periodic pressure pulses in the borehole zone of the reservoir in the form of a damped standing wave moving along the cavity of the well, using hydraulically mounted coaxial cylinders with a compressed gas inlet pipe, lateral outlet and pistons connected to each other use hydra forming an influential multiplier, a low-pressure cylinder mounted above a high-pressure cylinder mounted above the well valve, a negative pressure wave is created by discharging above the surface of the well fluid by supplying compressed gas through its inlet to the low-pressure cylinder under a pressure smaller by the ratio of the square of the diameters of the cylinders.

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 - pipe for supplying compressed gas; 8 - tap to drain the well fluid; 9 - tap drain well fluid.

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 low-pressure cylinder 5 has a nozzle for supplying compressed gas 7, the high-pressure cylinder 3 has a lateral outlet 9 for draining the well fluid, equipped with a valve 10.

The method is implemented as follows. Through the pipe 7 serves compressed gas, under the pressure of which the piston 6 moves up. The piston 4 connected to the piston 6 also moves up and creates a vacuum above the surface of the well fluid. A negative pressure wave is generated, 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.

Under the pressure of compressed air, both pistons continue to move upward, creating a depressive difference between the borehole zone of the formation and the cavity of the well and facilitating pumping of the liquid along with the disrupted adsorption deposits from the formation.

After processing the borehole zone of the formation, compressed gas is discharged from cylinder 5 and the valve 9 is opened. The well fluid located in cylinder 3 is discharged through outlet 8, pistons 4 and 6 are lowered under their own weight. Surfaced hydrocarbon contamination merges with the well fluid.

The cylinder 5 has a diameter larger than the cylinder 3, therefore, in order to obtain a pressure in the cylinder 3 sufficient for repression and depression of the pressure of the borehole fluid, a pressure lower than the ratio of the square of the diameters of the cylinders is applied to the cylinder 5.

After draining the liquid, close the tap and repeat the processing process until the required degree of purification of the borehole zone is achieved.

When cleaning the borehole zone of the formation, there is no need to create increased pressure in the well, therefore, it is possible to increase the power of a damped 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).

Since there is no need to pre-create pressure in the well, there is no danger of compaction of contaminants in the near-well zone of the formation when injecting fluid.

To create pressure in the cylinder 5, there is no need to use 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. Using rarefaction instead of overpressure in the well reduces the risk of pipe string rupture and cement stone damage.

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 a piston.

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.

The 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 for processing a borehole zone of a formation, including the formation of a depressurized differential pressure between the borehole zone of the formation and the cavity of the well with a negative pressure wave and the generation of periodic pressure pulses in the borehole zone of the reservoir in the form of a damped standing wave moving along the cavity of the well using coaxial cylinders mounted on the well with a nozzle compressed gas inlet, lateral outlet and with interconnected pistons, characterized in that they use forming hydraulic mu The low-pressure cylinder mounted above the high-pressure cylinder mounted above the well gate, a negative pressure wave is created by discharging above the surface of the well fluid by supplying compressed gas through its inlet to the low-pressure cylinder under pressure, which is less by the ratio of the square of the diameters of the cylinders.