METHOD FOR DETERMINING LOWER BOUNDARY OF OCCURRENCE OF PERMAFROST GROUND Russian patent published in 1999 - IPC

FIELD: oil and gas production industry. SUBSTANCE: this can be used in operation of producing wells in areas of parmafrost ground so as to preserve ground around mouth zone of well in frozen condition during entire service period of well. According to method, undertaken are geophysical investigations which consist in carrying out logging operations in drilled wells. Geothermal gradient is measured at 25-50 m intervals when performing logging operations. Obtained data are plotted in diagram, and straight lines are drawn through them which correspond to geothermal gradients in frozen and non-frozen zones. Conclusions are made according to crossing points of these straight lines about depth of lower boundary of occurrence of permafrost ground. Application of aforesaid method improves accuracy in finding required data. EFFECT: higher efficiency. 2 cl, 1 dwg