METHOD FOR PULSED WELL BOTTOM ZONE TREATMENT Russian patent published in 2007 - IPC E21B28/00 E21B43/25 E21B37/00 

FIELD: oil production industry, particularly to develop and clean oil production well bottom zone and equipment of asphalt-tar-paraffin deposits and mechanical impurities.

SUBSTANCE: method involves forming depression pressure drop between bottomhole formation zone and flow string interior by injecting fluid in hole annuity; releasing pressure as fluid intensively moves from bottomhole formation zone to day surface via flow string after rapid flow string interior opening by flow shutoff means; creating periodic depression-repression pressure pulses in bottomhole formation zone; controlling damped pressure oscillations with the use of wellhead pressure sensors; carrying out repeated pressure drop forming and pressure release cycles along with pressure pulse creation until current pressure drop formation time becomes equal to time of previous cycle. Sections to be treated are selected within perforation interval of casing pipe and each section is subjected to serial pulsed action by flow string movement for perforation interval section height. Depression pressure drop between bottomhole formation zone and hole annuity is created simultaneously with depression pressure drop between bottomhole formation zone and flow string interior. As fluid intensively moves from bottomhole formation zone to day surface via hole annuity after rapid flow string interior opening by flow shutoff means pressure is released. Periodic depression-repression pressure wave pulses between bottomhole formation zone and hole annuity are created simultaneously with creation of periodic depression-repression pressure pulses between bottomhole formation zone and flow string interior by damping hydraulic impacts by fluid flow commutation in hole annuity with the use of shutoff means. Intervals between time when reverse hydraulic impact pressure wave amplitudes reach maximal values during depression creation after simultaneous opening of shutoff means in flow string and hole annuity and time when amplitudes of pressure waves caused by hydraulic impact repression in flow string and hole annuity reach maximal value are determined. The hydraulic impacts are reflected from casing pipe perforation interval to be treated. Conditions to provide equal impact wave propagation velocities are created by shutoff means throat change. Then casing pipe, flow string and other equipment are flushed.

EFFECT: increased efficiency of bottomhole formation zone treatment by increased permeability thereof and improved cleaning of casing pipe interior, flow string interior and exterior surfaces, as well as another equipment installed in well.

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