TREATMENT METHOD OF BOTTOMHOLE ZONE Russian patent published in 2014 - IPC E21B43/25 

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 concept of the invention is as follows: a method includes injection of liquid to the borehole cavity, formation of depression pressure drop between the bottomhole zone and the borehole cavity by generation of periodical pressure pulses in the bottomhole zone as a wave moving through the borehole cavity, which is generated at periodical opening of the borehole cavity at the well head for discharge of the borehole fluid under pressure and its closing with the use of valves, opening and closing of the borehole cavity at the well head for discharge of the borehole fluid under pressure is made by a fluid discharge valve. Pressure in the well is from time to time raised by means of connection of the well cavity to the fluid source under pressure by opening of a fluid fill-up valve. At that at the first stage the bottomhole zone is treated by generation of the periodical pressure pulses as a shock wave moving through the borehole cavity generated at periodical opening of the borehole cavity at the well head for discharge and fill-up of the borehole fluid. At the second stage the bottomhole zone is treated by oscillations build-up in the borehole fluid with the working fluid injected into the well due to opening of the fluid release valve and the fluid fill-up valve with periodicity ensuring to-and-fro motion of the liquid weight. At the third stage the bottomhole zone is treated by oscillation of the well fluid mass due to opening of the fluid discharge valve and the fluid fill-up valve with periodicity providing resonant movement of its mass and circulation for backwash of the well. According to the invention at the second stage operations of the fluid mass oscillations are repeated periodically due to opening of the fluid fill-up valve only in order to increase pressure in the well and to open fractures in the formation to the maximum extent. Then operations of the fluid mass oscillations are repeated due to opening of the fluid discharge valve and the fluid fill-up valve in order to decrease pressure in the well down to the initial level.

EFFECT: invention provides development of fractures in the formation in the bottomhole zone due to their regular deformation by amplitude-varying pressure pulses with use of the working agent among other factors.