PROCESS OF OPERATION OF PRODUCTION WELL UNDER CONDITIONS OF EXPANSION OF ROCKS FROZEN FOR MANY YEARS Russian patent published in 2001 - IPC

FIELD: oil and gas production industry. SUBSTANCE: process refers to operation of oil, gas and gas condensate wells in zone of expansion of rocks frozen for many years. Process includes geophysical investigations, determination of thermal-physical properties, measurement of natural temperature of rocks frozen for many years. Computational mathematical model of geotechnical system " production well-rocks frozen for many years " is developed with the use of obtained data. It is based on solution of two- dimensional differential equation of heat conduction in cylindrical coordinates with mobile phase boundary in inhomogeneous media by numerical methods. Thermal interaction between elements of geotechnical system is modeled. Time of operation at which temperature on boundary " cement ring-rocks frozen for many years " at some depth gets equal to temperature of start of thawing of rocks frozen for many years is determined. Value of obtained time interval of operation is recorded. Mathematical " switching off " of well is executed by way of assignment of zero coefficient of convective heat transfer. Mathematical modeling with changed parameters is continued for period equal to period of operation recorded in preceding step. Value of coefficient of convective heat transfer is assigned again and modeling operations are repeated. Alternation of cycles different in time is produced. Modeling is conducted till duration of three sequential cycles of operation and shut-off of well equal one another. Obtained duration of them is sought-for value. Condition of operation of particular well is set for future on its basis. EFFECT: maintenance of stable thermal condition. 2 dwg, 1 tbl