WELL BOTTOMHOLE ASSEMBLY Russian patent published in 2008 - IPC E21B4/02 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to boring and can be implemented in assemblies of well bottomhole applied at boring of oil and gas wells. The assembly consists of hydraulic bottomhole motor including a case and a hollow output shaft connected to a chisel and a screw gerotor mechanism. Radial and thrust bearings are located in a lower part of the case of the motor. A case of the screw gerotor mechanism is tied by means of a pivot with a nipple installed in the lower part of the case of the bottomhole motor. At least one module with an interior screw surface is placed inside the gerotor mechanism, while at least one module with exterior screw surface is placed on the exterior surface of the hollow output shaft of the bottomhole motor; the said surface is in mesh with the above said module. Radial holes are made in the case of the gerotor mechanism; these holes connect an inside cavity of the case with the well.

EFFECT: increased efficiency of boring process due to reduction of differential pressure onto bottomhole.

4 cl, 3 dwg