METHOD FOR CONSTRUCTION OF WELLS Russian patent published in 1998 - IPC

FIELD: oil and gas production industry. SUBSTANCE: this particularly relates to construction of wells in permafrost ground. Application of method ensures retaining integrity and tightness of production string in any conditions of freezing water-bearing media both in casing clearance and in annular space. Method implies locating in well casing pipes of various strength. Initially, proceeding from conditions of fail-safe construction of wells with respect to strength characteristics, selected is casing pipe which is nearest to production string. After that, preset is permissible external pressure of crushing production string. It must be higher than total pressure corresponding to ultimate breaking strength of casing pipe closest to production string and breaking pressure of frozen ground. Production string is selected according to aforesaid value. Strength characteristics of each subsequent casing pipe are preset proceeding from conditions of permissible pressure with respect to ultimate strength of internal casing pipe. EFFECT: higher efficiency. 1 dwg