METHOD PREVENTING CASING COLLAPSE IN WELL IN ZONE OF ROCKS FROZEN FOR MANY YEARS Russian patent published in 2003 - IPC

FIELD: oil and gas production, construction and operation of oil and gas injection wells in permafrost zones. SUBSTANCE: method includes use of channel along walls of casing string heated by heating element for removal and discharge of excess of fluid from cavern, consistent freezing of cavern from below to top, keeping of channel in heated state above frozen cavern. Hollow drain channel in the form of string of filtering pipes fitted with heating element formed artificially in close proximity to casing string, along its wall to depth of permafrost bedding is utilized to discharge excess of fluid from cavern. Heating element is mounted for replacement, is fitted with automatic aids for monitoring and control over supply of electric energy to it. Duration of maintenance of drain channel in heated state is determined by time interval of complete freezing of cavern which is indicated by cessation of discharge of fluid from drain channel and by automatic switching off of supply of electric energy to heating element. EFFECT: reduced expenses for obtainment of initial data and for realization of method, exclusion of any additional measures and expenses for continuation of construction and for resumption of operation of wells, raised possibility of control over process execution and its termination. 1 dwg