METHOD FOR ASSESSING QUALITY OF CASING WELLS IN PERMAFROST AND LOW-TEMPERATURE GROUND Russian patent published in 1997 - IPC

FIELD: construction of oil and gas wells. SUBSTANCE: according to method, measured are density and temperature of plugging solution and forcing-through liquid, diameters of cemented casing string and of open bore-hole, temperature in well during cement slurry hardening period. Additionally measured are temperature of rocks which surround well, of drill mud during drilling and flushing, temperature of casing string before lowering into well, of drilling and plugging solutions at well head. These data are used to determine within investigation intervals the total heat emitted by plugging solution in annular space, also heat emitted by cement ring and redistributed in it and in well surrounding rocks, heat emitted by forcing-through liquid and casing string during period from end of cementation to moment of starting investigation, also total amount of heat emitted by 1 kg of plugging solution when it fills entire annular space at moment of investigation, determined are intervals and radius of zone of absorbing drill and plugging solutions, also determined is value of criterion of string cementation quality. EFFECT: high efficiency. 3 cl, 2 dwg