METHOD AND DEVICE FOR SAND PLUG REMOVAL FROM WELL BOTTOM AND GRAVEL FILTER AGGREGATION Russian patent published in 2005 - IPC

FIELD: oil and gas production, particularly to wash out and remove sand from well bottom and to aggregate gravel filter at well bottom.

SUBSTANCE: method for washing out sand plug at well bottom and carrying thereof to ground surface, arranging sand filter within predetermined interval and aggregating gravel filter in space behind the filter involves lowering sand filter and packer carried by pipe string in the well and flushing sand with flushing liquid under hydraulic pressure. The sand filter is provided with means creating high-pressure jet of flushing liquid having stem of removable packer part, packing gland and check valve with choke diaphragm. Distribution device provided with inner and outer bushes is arranged above the sand filter. After sand plug flushing out and removal and sand carrying out sand filter is installed within the given interval, inner and outer spring-loaded bushes are lowered by dropping a ball into pipes of the string. Gravel filter is aggregated by passing thereof through the pipes under elevated pressure into space located behind the filter between sand filter and filtering zone of the bed along with working fluid injection in hole annuity to prevent gravel level lifting above filter one. After that gravel and liquid supply is stopped and gravel is forced from pipes into the bed. Stem of removable packer part is lifted above packing gland to carry the ball to ground surface by reverse circulation creation and then the packers are set. Device comprises sand filter carried by pipe string and gravel supply unit arranged above the sand filter. To remove sand plug from well bottom device additionally has packer with removable upper part provided with stem, packer gland and check valve having chick diaphragm. The check valve is arranged under packing gland. Gravel supply unit is formed as distribution device with inner and outer spring-loaded bushes. Inner spring-loaded bush has seat for receiving ball to be dropped in the pipe.

EFFECT: increased overhaul time, reduced well repair time and quality due to decreased number of trips.

5 cl, 2 dwg