RU2255214C1 - Method for processing well-adjacent bed zone - Google Patents

Abstract

FIELD: mining industry.

SUBSTANCE: processing periods include forming of depression pressure change between well-adjacent bed zone and well hollow. Cleaning of well-adjacent bed zone is performed by prior feeding of fluid into well, forming of periodic pressure pulses in well-adjacent bed zone in form of fading standing wave, moving along the well, and decreasing pressure during fluid movement along well from well-adjacent bed zone to day surface for extraction of clogging. Plant for washing wells is used, which is connected to behind-pipe space of well and to tubing pipe. Behind-pipe space of well is isolated by packer along lower limit of perforation range. Perforation range is filled with sedimentation, formed from destroyed rock, and accumulated above packer as a result of gradual and even cleaning of well-adjacent bed zone along whole length of perforation range. Packer is disabled and well is washed clean, without raising tubing pipes column.

EFFECT: higher efficiency.

1 dwg, 1 ex

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 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.

There is a 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 using which they are 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 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 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 N.B. et al. Patent No. 2159326, class E 21 V 43/25), taken as a prototype, in wherein the formation of a depression of the pressure differential 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 along kvazhine of the well bore formation zone to the surface at a sharp opening borehole cavity.

However, contaminants are removed unevenly from the perforation of the borehole and the near-wellbore zone of the formation; after processing, the zones remain sealed.

The objective of the invention is to clean the area of the reservoir adjacent to the bottomhole zone of the well along the entire length of the perforation interval.

The problem is solved by the fact that, using a method of processing the borehole zone of the formation, containing treatment periods, including the formation of a depressurized pressure differential between the borehole zone of the formation and the cavity of the well, for cleaning said borehole zone of the formation 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 well and pressure relief when the fluid moves through the well from the near-well zone of the formation to the day surface for the removal of contaminants using a well flushing unit, a well flushing unit is connected to the annular space of the well and to the tubing, the annular space of the well is isolated with a packer along the lower boundary of the perforation interval and, as the perforation interval fills with sediment formed from destroyed rock and accumulating over the packer as a result of gradual and uniform cleaning of the borehole formation zone along the entire length of the perforation interval, turn off the packer and flushing the well without lifting the tubing string.

This method allows to increase the overhaul period of the well due to better decolmatization of the borehole formation zone.

An example of a device for implementing the proposed method is illustrated in the drawing, in which: 1 - pipe annulus; 2 - tubing; 3 - packer; 4 - sediment.

The method is implemented as follows.

The installation for washing the wells is connected to the annulus of the well through the pipe 1 and the tubing 2. The annulus is isolated by a packer 3 along the lower boundary of the perforation interval.

Fluid is pumped into the well using the pump of the installation through the pipe of the annulus 1 and a pressure is created that is safe for the integrity of the casing and cement stone. Under the influence of excessive pressure, the fluid penetrates into the borehole zone of the reservoir.

For the formation of a standing shock wave, the cavity of the annulus is opened and, when a sufficient flow rate of the fluid is reached, the flow is blocked. 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-depressive impulses make it possible to disrupt adsorption deposits on the walls of pore channels, as well as create cracks in the skeleton of the formation and break off its fragments.

The formation of a standing shock wave is also possible by shock application of pressure to the surface of the borehole fluid at the wellhead, while the packer serves as a deflector of the shock wave and directs it to the borehole zone of the formation through the lower part of the perforation interval.

After the oscillations of the standing shock wave are attenuated, the well fluid is poured out to move viscous contaminants, solids and fragments of the destroyed rock from the near-wellbore zone of the formation into the well cavity, while light constituents float to the surface, fragments of the destroyed rock and solids accumulate above the packer, forming sediment 4.

During the repeated formation of the shock wave and its passage through the annular space, the deflector is sediment 4 of fragments of destroyed rock and mechanical impurities removed from the formation. Perforation and the formation zone above the sediment 4 are processed. Thus, as sediment 4 accumulates, the near-wellbore zone of the formation is gradually and uniformly processed along the entire length of the perforation interval.

As the sediment fills the perforation interval, which is recorded by a sharp increase in the resistance to fluid injection or by a change in the strength of the reflected shock wave, the packer is turned off and the well is flushed directly or backward without lifting the tubing string. The processing and flushing processes are repeated until the necessary degree of purification of the borehole zone and well cavity from viscous and solid contaminants is achieved.

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 treating a wellbore zone of a formation comprising treatment periods including the formation of a depressurized differential pressure between the wellbore zone of a formation and a well cavity for cleaning said wellbore zone of a formation by first pumping fluid into a well, generating periodic pressure pulses in the wellbore zone of the formation in the form of a damped standing wave traveling along the well, and bleeding pressure when moving the fluid through the well from the near-wellbore zone of the formation to the day surface to remove contaminations using a well wash facility, characterized in that the well wash facility is connected to the annulus of the well and to the tubing, the annulus of the well is isolated with a packer along the lower boundary of the perforation interval and as the perforation interval fills with sediment formed from the destroyed rock and accumulating over the packer as a result of gradual and uniform cleaning of the borehole zone of the formation along the entire length of the perforation interval, turn off the packer and carry out washing the wells without lifting column of tubing.