Analysis On High Temperature And High Pressure Gas Well Integrity In Keshen Block Of Tarim

Alone with constantly development of conventional reservoir,the oil production gradually turns to the deep,high temperature and high pressure reservoir.Now,the well average depth in Keshen block is 6800 m with the characters of high temperature and high pressure.They are typical three-high wells.Also,the bad formation conditions and working conditions bring huge challenges to the primary and secondary well barriers.In order to ensure the safety and efficient production of Keshen block,it is very necessary to research and analyze its integrity.This paper bases on the geological features of Keshen block,starts with the temperature and pressure field.Through analyze the process of fluid power and the component of pressure drop,establishes the mathematical models of temperature field and pressure field,and analyze the model affection factors as production time and the relative density of the gas.Analyzes mechanics features of borehole diameter mutation.Establishes deformation mathematical models of strings under the effects of temperature and pressure.Puts forward the annuls pressure drop during acidizing,and cause string triaxial safety coefficient drops,needing to redesign the strings.Aiming at casing wear causing by slow drilling speed and the failure of secondary well barrier,summarizes the main factors causing casing wear.Calculate the casing contact force and the wear depth with using the crescent model.Taking wear casing as original defects and considering the effects of roundness and wall thickness variability,calculate the residual strength of casing wear.Combining with the field data,casing wear depth of X well and residual strength biggest drop are more than 30%.