RU2383720C1 - Procedure of well bottomhole zone treatment - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to mining and can be used for development and rejuvenation of production well yield dropped because of bottomhole zone mudding with asphalt-pitch-paraffin formations and mechanical impurities. The procedure consists in pumping fluid into a well, in forming a depression differential between the bottomhole zone and cavity of the well by generating periodic pressure pulses in the bottomhole zone in form of a wave spreading along cavity of the well and produced at periodic opening cavity of the well at the wellhead for well fluid under pressure flowing out, and at its closing by valves; one of the valves designed for fluid draining connects cavity of the well with a drainage tank, while the second valve - the valve of fluid topping up- connects cavity of the valve with a source of fluid under pressure. Cavity of the well at the wellhead for draining well fluid under pressure is closed and opened by means of a fluid draining valve. Pressure in the well is periodically built up by connecting the wellhead with the source of fluid under pressure by opening the valve of fluid topping up. According to the invention the wellhead is preliminary connected with a receiver filled with gas. The valve of fluid draining is opened through a valve while the above said valve is closed. Further, the valve connecting the wellhead with the receiver is opened in an interval of time sufficient for forming an impact wave of depression. The valves open with frequency facilitating excitation of fluid weight in a resonance mode.

EFFECT: facilitating increased efficiency of procedure due to combining pulses of depression and excitation of weight of column of well fluid into condition of resonance reciprocal motion.

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Description

The present 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 bottomhole zone with asphalt-resin-paraffin formations and solids.

A known method of processing the bottom-hole 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. E21B 43/25), 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, tubing, equipment and cable using a winch, 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. Е21В 37/00), in which they periodically create at the wellhead waves of negative pressure, for which they block the valves on the flow line and maintain it in the closed state, then open.

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

There is a method of developing and cleaning the bottom-hole zone of wells by pulsed drainage (Nosov P.I., Senochkin P.D., Nurislamov N.B. et al. Patent No. 2159326, Cl. Е21В 43/25), in which the formation of a pressure drop between the bottom-hole zone of the formation and the cavity of the well is made by preliminary pumping fluid into the well, creating periodic pressure pulses in the bottom-hole zone of the formation in the form of a damped standing wave moving along the cavity of the well, and relieving pressure when the fluid moves through the well from the bottom-hole the formation to the day surface with a sharp opening of the well cavity.

However, the bottom-hole zone is poorly washed by well fluid since the water hammer has a short exposure time during which the formation cracks do not have time to fully open and close during the impact.

A known method of processing the borehole zone of the formation (Shipulin A.V., Patent No. 2266404, Cl. EVB 43/25), taken as a prototype, including the creation of periodic pressure pulses in the borehole zone of the formation in the form of a shock wave moving along the cavity of the well, generated during periodic opening well cavities at the wellhead using valves, one of which connects the well cavity to a drain tank, the second to a source of pressurized fluid.

However, the bottom-hole zone is poorly washed by well fluid since the water hammer has a short exposure time during which the formation cracks do not have time to fully open and close during the impact.

The objective of the invention is the combination of methods for creating in the bottom-hole zone of pulses of depression and bringing the mass of the column borehole fluid into a state of resonant reciprocating motion.

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 cavity of the well at the mouth for the outflow of well fluid under pressure and its closure using valves, one of which is a valve l the fluid drain connects the well cavity with the drain tank, the second — the fluid filling valve — with the source of pressurized fluid, the opening and closing of the well’s cavity at the mouth for leakage of the pressurized well is carried out by the fluid drain valve, and the pressure in the well is periodically increased by connecting the wellhead to a source of liquid under pressure by opening the valve topping up the fluid, the wellhead is previously connected to the receiver filled with gas through Thiel, when the above-mentioned valve closed fluid drain valve open, and then, after a time sufficient for the formation of a shock wave depression, open valve which connects the wellhead to the receiver, the valve opening is performed with a periodicity which provides its swinging mass in resonance mode.

This method allows for the implementation of the resonant reciprocating movement of the mass of the column of well fluid immediately before moving from the bottom-hole zone to the mouth to carry out a depressive hydraulic shock in order to detach deposits from the walls of cracks and pore channels and their subsequent removal into the well cavity.

The method is implemented as follows. At the wellhead, valves are installed, the first of which connects the tubing cavity to the drainage tank, the second - the annulus with a source of fluid under pressure, for example, a fluid line designed for injection into injection wells or a CA-320 unit, and the third - the wellhead with a receiver containing an inert gas safe for work. Liquid is pumped into the well cavity to a technologically permissible pressure.

With a closed valve connecting the wellhead to the receiver, open the drain valve. Downhole fluid begins to pour into the drain tank, the fluid pressure at the wellhead drops sharply to atmospheric pressure, a rarefaction wave forms, which moves from the wellhead to the bottom of the well and forms a depression impulse in the bottomhole zone.

The depression pulse contributes to the separation of adsorption deposits from the walls of the pore channels and cracks, their removal from the pores and cracks of the reservoir.

After a period of time sufficient to form a shock wave of depression, open the valve connecting the wellhead with the receiver. When the drain valve is closed abruptly, due to the inertia of its mass, the well fluid fills the receiver and compresses the gas. After maximum compression, the gas expands and expels the fluid from the mouth to the bottomhole zone. The well fluid is brought into a state of vertical reciprocating vibrations. The moving mass of liquid is reflected from above by compressing gas, from below - by expanding and closing fractures of the formation.

Before creating another depressive effect on the bottom-hole zone, the valve connecting the wellhead to the receiver is closed.

The oscillation resonance is supported by periodic sequential opening and closing of the valves connecting the wellhead to the receiver and the drain tank with a frequency determined by the depth of the well, pressure and viscosity of the fluid and selected experimentally.

The movement of the mass of fluid in the cavity of the well contributes to the creation of significant pressure drops in the near-wellbore zone, as well as its flushing, extraction of deposits and rock fragments, destroyed by depressive hydraulic shock.

In the process of treatment of the bottom-hole zone, the valve for adding fluid is periodically opened and the pressure in the well cavity is increased to a technologically acceptable level.

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 zone of a well, including pumping a liquid into a cavity of a well, forming a pressure drop between the bottom hole and a well cavity by creating periodic pressure pulses in the bottom hole in the form of a wave generated during the periodic opening of the well cavity at the wellhead for leakage liquid under pressure, and closing it using valves, one of which is a liquid drain valve that connects the cavity of the wells with a drain tank, the second is a fluid filling 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 to the source fluid under pressure by opening the valve topping up, characterized in that the mouth of the well is pre-connected to the receiver filled with gas through the valve, when closed The aforementioned valve opens the fluid drain valve, then, after a period of time sufficient for the formation of a shock wave of depression, the valve connecting the wellhead to the receiver is opened, the valves are opened with a periodicity that ensures its mass buildup in resonance mode.

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