METHOD OF DETERMINATION OF SIZES AND CONFIGURATION OF THAWED ZONE OF PERMAFROST ROCKS IN WELLHEAD ZONE Russian patent published in 2000 - IPC

FIELD: oil and gas producing industry; applicable in development of oil and gas deposits located in zone of permafrost rocks. SUBSTANCE: method includes standard thermal investigations of ground, thermometric measurements for obtaining the initial parameters for further calculations. Thermal interaction of well with permafrost rocks is determined by solution with help of digital methods based on mathematical modelling of nonstationary equation of heat conduction for time period since well purring into service up to end of season of summer thawing of grounds. Then, values of temperatures of heat field are registered, profile of position of rock phase boundary at different depths is constructed and sizes of thawed zone are determined. Calculated for obtained thawed zone is value of settlement of thawed rocks in wellhead zone for calculated period at different distance from well with use of offered formulas. Calculation results are used for determination of radius at different depths of formed thermokarst crater and construction of scale profile of said thermokarst crater. Calculated value of settlement of thawed rocks is used for determination of configuration of calculated region of heat model, and above described operations are repeated for next year cycle. Calculation cycles are repeated up to attaining the preset moment of time. In case preset moment of time does not coincide with time of end of summer thawing of grounds, calculation of rock settlement and construction of scale profile of thermokarst crater are performed for preset moment of time. EFFECT: higher accuracy of determination of reliable values of sizes and configuration of thawed zone of permafrost rocks in wellhead zone for preset moment of well operation. 2 cl, 4 dwg, 1 tbl