STEPPED BUSHING FOR MULTISTAGE HYDRAULIC FRACTURING IN ONE ROUND TRIP OPERATION Russian patent published in 2013 - IPC E21B34/14 E21B43/26 

FIELD: mining.

SUBSTANCE: fluid supply device features sensor of plugs (darts, balls, etc.) passing through tool. Actuator shifts tool insert after a preset number of plugs has passed through tool. Insert shift opens catcher in tool bushing. After next plug discharge, catcher connects to the plug in bushing so that fluid pressure applied to the plug installed in tubing string can move the bushing. Shifted bushing opens windows in tool, connecting tool channel to surrounding annular space, thus enabling treatment of formation interval adjoining well shaft to intensify flow. Actuator can use sensor of plugs passing through tool. Spring housed in tool can bend at approach to sensor when a plug passes tool, and sensor counts number of plug passes.

EFFECT: enhanced efficiency of multistage hydraulic fracture in one round trip operation.

32 cl, 25 dwg