CASING PIPE Russian patent published in 1994 - IPC

FIELD: oil industry. SUBSTANCE: casing pipe comprises pipe body having union joints mounted on its ends and longitudinal ribs evenly disposed over pipe periphery. Outside diameter of pipe over ribs is equal to outside diameter of joint. Rib height is determined from relationship given in specification, the number of ribs being chosen as equal to 1/12 outside conventional diameter of casing pipe, the foot length as equal to 1/50 perimeter of casing, and the radii of tops and bottoms of ribs as not exceeding 1/2 length of the latter. EFFECT: casing landing reliability increased. 2 dwg, 1 tbl