RU2330953C1 - Method of treatment of bottomhole zone of bed - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to mining and can be used for development and rejuvenation of producing wells yield, reduced as a result of mudding of a bottomhole zone with asphalt-tar-paraffin formations and mechanical additives. The method of treatment of a bottomhole of a well includes formation of a depressive pressure drop between the bottomhole zone and a reservoir of the well by means of a shock wave, relocating in the well reservoir and creating recurrent pressure impulses in the bottomhole zone. The said shock wave occurs with alternate opening of the well reservoir at the mouth of the well for well fluid under pressure flowing out, and with its closing by means of valves. One of these - the fluid discharge valve - connects the well reservoir with a discharge reservoir; the second - the fluid refill valve - connects the well reservoir with the fluid source under pressure. Opening and closing of the well reservoir at the mouth for discharge of the well fluid under pressure is performed by means of the fluid discharge valve. Pressure in the well is from time to time raised by means of connection of the mouth of the well with the fluid source under pressure when the fluid refill valve is opened. Opening and closing of the well reservoir at the mouth is performed so, that vacuum and pressure spaces of the shock wave relocating in the well reservoir coincided in the phase with periodical dropping and rising of pressure in the bottomhole zone.

EFFECT: achieving the efficient method of bed bottomhole zone treatment by means of increasing amplitude of a damped standing wave in the bottomhole zone when this wave if transferring in the well reservoir.

Description

The present invention relates to mining and can be used to develop and restore the production rate of production wells, decreased due to 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 E21B 43/25), 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, class Е21В 43/25), when using which an implant device is lowered into the well they pump the treatment compound, push it into the reservoir, and carry out cleaning by creating multiple implosive effects.

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., Aliyev E.N. Patent No. 1700207, class E21B 37/00), in which waves are periodically generated at the wellhead negative pressure, for which they block the valves on the flow line and maintain it in the closed state, then open.

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 ensure 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 NB and others. Patent No. 2159326, CL ЕВВ 43/25), taken as a prototype, in which the formation Depression of the pressure drop between the borehole zone of the formation and the well cavity is done by preliminary 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 moving the fluid along borehole from the near-wellbore zone of the formation to the day surface with a sharp opening of the well cavity.

However, the shape of a decaying standing wave is formed due to the interference of rarefaction and pressure waves that occur when opening and closing the wellhead, depends on their phase shift and can be distorted in shape and reduced in amplitude.

The objective of the invention is to increase in the bottom-hole zone the amplitude of the decaying standing wave propagating through the cavity of the well, due to the coincidence in phase of the waves of rarefaction and pressure that occur when opening and closing the wellhead.

The problem is solved in that, using a method for processing the bottom-hole zone of a well, including pumping a liquid into the cavity of the well, forming a depressive differential pressure between the bottom-hole zone and the cavity of the well by creating periodic pressure pulses in the bottom-hole zone in the form of a shock wave moving along the cavity of the well, which is generated during periodic opening the well cavity at the mouth for leakage of well fluid under pressure and closing it using valves, one of which is a valve a fluid drain connects the well cavity with a drain tank, the second — a fluid filling valve — with a source of pressurized fluid, opening and closing the well cavity at the wellhead for leakage of the pressurized fluid, is carried out by a fluid drain valve, and the pressure in the well is periodically increased the connection of the wellhead with a source of fluid under pressure by opening the valve topping up the fluid, closing and opening the cavity of the well at the mouth is carried out with such a calculation, so that the regions of rarefaction and pressure of the shock wave moving along the well cavity coincide in phase with periodic decreases and increases in pressure in the bottom-hole zone.

This method allows you to rationally use the total reservoir, hydrostatic and dynamic pressure in the bottomhole zone of the well to obtain the maximum amplitude of its differential.

The method is implemented as follows. At the wellhead, completely filled with fluid, a fluid flow interrupter is installed, equipped with a timer for opening and closing at predetermined times.

When the flow breaker is opened, the borehole fluid is poured out of the borehole with increasing speed, a rarefaction wave is formed in the borehole cavity, propagating from the wellhead to the bottomhole zone. When a well is closed, a sharp stop of the flow occurs with the formation of a water hammer and the propagation of a pressure wave from the wellhead to the bottomhole zone.

A standing wave in a well cavity is formed by the action of rarefaction and pressure waves. The opening and closing of the fluid flow interrupter is carried out in such a way that the amplitudes of the rarefaction shock waves and the pressure with the differences caused by the action of previous shock waves are summed in the bottomhole zone of the well.

Repression and depression impulses make it possible to disrupt adsorption deposits on the walls of the pore channels and contribute to the cleaning of the bottom-hole zone of mud deposits.

The process is carried out until the required degree of bottom-hole treatment is achieved.

The application of the invention will allow the processing of the borehole zone of the formation, as well as the impact on the formation of alternating pressure strokes of maximum amplitude without the use of special equipment and attracting a minimum amount of labor.

The described method is applicable both to wells equipped and not equipped with a tubing string, it 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 productive processing. 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 a bottom hole of a well, including pumping a liquid into the cavity of a well, forming a pressure drop between the bottom and the well cavity by creating periodic pressure pulses in the bottom in the form of a shock wave moving along the well cavity, which occurs when the hole is periodically opened at the wellhead for leakage well fluid under pressure, and closing it using valves, one of which is a fluid drain valve that connects the strips b wells with a drain tank, the second is a fluid top-up valve with a source of pressurized fluid, opening and closing the well cavity at the wellhead for the flow of pressurized wellbore is carried out by a fluid drain valve, periodically increase the pressure in the well by connecting the wellhead with a source of liquid under pressure by opening a valve topping up the liquid, characterized in that the closing and opening of the well cavity at the wellhead is carried out so that and the vacuum pressure and the traveling of the well cavity of the shock wave is in phase with periodic depressions and elevations in the bottom hole pressure.