WELL BOTTOM ZONE TREATMENT METHOD Russian patent published in 2006 - IPC E21B37/06 

FIELD: oil industry, particularly to stimulate or resume oil and gas well operation by performing thermal-chemical treating and cleaning of well bottom zone to remove deposits, namely asphalt-tar and paraffin deposits.

SUBSTANCE: method involves lowering flow string in well interval to be treated via casing pipe; supplying heat-generating substances; creating increased pressure; treating bottomhole formation zone; performing technological time delay and applying depression action to heated zone to be treated. Lower part of flow string is provided with uncontrollable plug valve, which is pinned to flow string and defines sealed cavity along with flow string interior. As flow string is lowered in well hydrogen peroxide is supplied in flow string. Then hydrogen peroxide-neutral acetate buffer solution is fed and the buffer solution is isolated from hydrogen peroxide with uncontrollable plug valve. 5% manganese solution and water are supplied in well. Acetate buffer solution has density exceeding that of manganese solution. Manganese solution density exceeds water density. After flow string lowering in well backpressure is created in well interval to be treated by filling space between casing pipe and flow string with water. Then pressure is increased in flow string. Once pressure jumps water is supplied via flow string in well interval to be treated. After technological time delay execution bottomhole formation zone is subjected to depression action by flushing thereof with aerated acetate buffer solution.

EFFECT: increased efficiency of well bottom zone treatment.

1 dwg