PLANT FOR WELL DRILLING AND WELL FACE CLEANING WITH FOAM Russian patent published in 2006 - IPC E21B21/14 

FIELD: well drilling equipment, particularly for flushing boreholes using liquids and gases, for instance foams.

SUBSTANCE: well drilling plant is drilling rig comprising two compressors used for foam preparation. The plant has hoisting unit, rotary device to rotate drill column having swivel, low pressure air pump and circulation system having foam generation device, foam breakdown unit and sludge separator. Foam generation device has booster with hydraulic seal and with reciprocating pumping unit, as well as force pump for hydraulic seal forming. Booster communicates with mixing vessel from one booster side and with sludge separator from another side thereof. The mixing vessel has swivel and inlet means for emulsifier. The mixing vessel is connected with the booster through fluid flow rate and density metering unit. The sludge separator communicates with the booster through control throttle and is connected with well head through foam breakdown booster including low pressure degassing separation means and demulsifying agent supply means and with the booster through supply pump. Low pressure air pump communicates with the booster through gas-separation membrane assembly. Foam breakdown unit communicates with hydrocarbon gas combustion means, which combusts hydrocarbon gas as it comes from the well. Well head equipment includes well head sealer, for instance rotary preventer.

EFFECT: possibility to drill long wells during opening of low-pressure hydrocarbon deposit due to high-pressure foam supplying to well face, prevention of explosive mixture formation as a result of hydrocarbon gas emission.

4 cl, 1 dwg