CASING CENTRALIZER Russian patent published in 2003 - IPC

FIELD: hole clearance cementation, casing string centering in hole. SUBSTANCE: casing centralizer has cylinder, plug in shear communicating space of cylinder with space inside string, piston, centering members. Cylinder is made fast to casing string, lower part of piston is conical. Centering members come in the form of tabs of conical bushing that has annular groove around edges on outside. Cylindrical part of conical bushing is made fast to casing string. Lower conical part of piston interacts with split tabs of conical bushing. EFFECT: simplified design and raised operational reliability of casing centralizer. 1 cl, 3 dwg