METHOD FOR ISOLATION OF RESERVOIR WATER INFLOW IN WELL WITH BUCKLED FLOW STRING UNDER CONDITIONS OF ABNORMALLY LOW RESERVOIR PRESSURES Russian patent published in 2010 - IPC E21B43/32 

FIELD: oil and gas production.

SUBSTANCE: sand plug is washed down to lower perforation holes of existing interval of perforation, and buckling of flow string is eliminated. Then water-insulation composition is injected into existing interval of perforation, is pushed into reservoir, creating a water-insulation screen, and displacing reservoir water in depth of reservoir by displacement fluid. Then tail of smaller diametre pipes is lowered in inner cavity of flow string to head of washed sand plug, with arrangement of tail head by 20 m higher than reservoir roof, which is cemented by mortar, leaving cement sleeve in inner cavity of tail down to depth of 1-2 m higher than current gas-water contact and higher than upper holes of existing perforation interval. As cement hardening waiting time elapses, two strings, tail and operating strings are perforated for operation, in interval above the cement sleeve to roof of reservoir. Then lifting string is lowered in well by 1-2 m higher than the tail head. Gas flow is caused from reservoir, and well is flared. Gas dynamics research is carried out, and the well is commissioned. At the same time water-insulation composition is represented by liquid glass, displacement fluid - by methanol, cement mortar is a composition that consists of portland cement, superplasticiser C-3, polyvinyl alcohol and polypropylene fibre.

EFFECT: liquidation of reservoir water inflow and elimination of flow string buckling conditions, provision of water-free operation of wells and getting planned volumes of gas production.

1 ex, 4 dwg