DEVICE FOR WELL DRILLING IN COMPLICATED BED Russian patent published in 2012 - IPC E21B7/20 

FIELD: gas and oil production.

SUBSTANCE: device includes casing string, drilling tool with submersion bottomhole motor and fuel circulation system in the form of hollow injection pipe, spline coupling. Casing string length suffices to overlap complicated bed and is made in the form of connected sections of multipath pipes with lengthwise crimping, and features bottom adapter with injection pipe inserted tightly in the lower part and removable top adapter connected tightly to string top end in the upper part, and with injection pipe inside. Top adapter features longitudinal recesses matching splines on the external surface of process bushing inserted from top, and capable of longitudinal travel into casing string outside of injection pipe, and positioned in respective crimps of the upper part of multipath pipes. Bottomhole motor is connected rigidly to bottom adapter which features fishing tool on top for fishneck and can be removed from casing string after the fishing tool catches fishneck. Injection pipe space features ducts connected to internal space of casing string and blocked tightly by a bushing fixated in travel position, equipped with a seat for wire line ball and capable of limited travel down to open ducts.

EFFECT: extended technical possibilities of device, prevention of hazardous loads for casing string.

3 dwg