RU2327027C2 - Processing method of bottomhole zone - Google Patents

Abstract

FIELD: mining engineering.

SUBSTANCE: one pumps fluid into borehole cavity. Then depression differential pressure is formed between bottomhole zone and borehole cavity creating repetitive pressure pulses in bottomhole zone as moving in borehole cavity impulse wave. It is created while periodic opening of borehole cavity in mouth for bore-hole fluid effluxion which is under pressure, and its closing with the usage of ball checks. One of them is fluid effluxion ball check connects borehole cavity with dump tank, another - filling fluid ball check - with fluid source which is under pressure. Opening and closing of borehole cavity in mouth for borehole fluid effluxion, which is under pressure, is made with the help of fluid effluxion ball check. According to invention opening of fluid effluxion ball check is made with the speed, providing sudden drop in pressure in borehole mouth to atmospheric, and closing - with the speed in 2-5 times lower the speed of its opening.

EFFECT: creating of periodic pressure impulses in bottomhole strata zone, when depression impulse has greater pulse height than repression impulse.

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 change in pressure 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 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. E21B 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 pre-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 bleeding off the pressure when moving the fluid through the well from the bottom-hole ons of the formation to the day surface with a sharp opening of the well cavity.

However, the method is applied only during the overhaul of the well using tripping and flushing the well through the annulus.

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, when alternating depressive and repressive influences, the latter are directed from the well into the reservoir and facilitate the movement of muds into pores and cracks, which affects the permeability of the bottom-hole zone.

The objective of the invention is the creation of periodic pressure pulses in the bottomhole formation zone, of which the depression pulse must have an amplitude greater than the repression pulse.

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 draining the fluid - connects the well cavity with a drain tank, the second - the valve topping up the fluid - with a source of fluid under pressure, opening and closing the cavity of the well at the mouth for leakage of well fluid under pressure, carry out the valve drain fluid, periodically increase the pressure in connecting the wellhead with a source of liquid under pressure by opening a fluid filling valve, characterized in that the opening of the fluid drain valve is carried out at a speed view, providing a sharp drop in pressure at the wellhead to atmospheric pressure, and closing at a speed 2-5 times lower than the speed of its opening.

This method allows for well treatment using a significant in amplitude and short in time depressive pulse of hydraulic pressure, as well as a relatively small in amplitude and longer pulse of repression.

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 CA-320 aggregate. The fluid is pumped into the annulus to a technologically permissible pressure.

At the moment of opening the drain valve, the well fluid begins to pour into the drain tank, the pressure of the fluid 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. When the fluid drain valve is closed and the moving fluid flow is interrupted, a high pressure region is formed at the wellhead, which moves from the wellhead to the bottom of the well and generates a repression pulse in the bottomhole zone. Periodic opening and closing of the drain valve leads to the regular passage of pressure waves and rarefaction along the tubing cavity.

The pressure and rarefaction waves, moving along the well cavity from the wellhead to the bottom and back, create shocks, including in the bottomhole zone, and contribute to the separation of adsorption deposits from the walls of the first channels and cracks, destruction of the formation skeleton. The periodic alternation of pulses of low and high pressure contributes to the loosening and chipping of low-permeability fragments of the reservoir.

Impulses of depression contribute to the extraction of colmatants from pores and fractures of the formation, their output into the cavity of the well. Repression impulses contribute to the compaction of colmatants in the reservoir. The most rational alternation of a sharp implosion impulse and a smooth increase in pressure in the bottomhole zone of the well.

The amplitude and duration of the depression pulse depends on the steepness of the front of the rarefaction wave, therefore, on the acceleration of the fluid flow when the drain valve is opened. The amplitude and duration of the repression pulse depends on the steepness of the front of the pressure wave, therefore, on the rate of interruption of the fluid flow when closing the drain valve.

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 of a well, including pumping a fluid into a 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 well cavity is periodically opened at the wellhead borehole fluid under pressure, and closing it using valves, one of which is a fluid drain valve that connects wells with a drain tank, the second is a fluid top-up valve with a source of pressurized fluid, opening and closing a well cavity at the wellhead for pressurized well to flow out 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 the valve topping up the liquid, characterized in that the opening of the valve to drain the liquid is carried out at a speed that provides a sharp drop pressure at the wellhead to atmospheric pressure, and closing - at a speed of 2-5 times lower than the speed of its opening.