Research On The Prediction Model Of Sustained Casing Pressure Caused By The Leakage Of Gas Well Tube

Aiming at the leak of tube thread within the gas wells,this paper focuses on the leak characteristic of non-API thread,and defines the tiny space is the potential leak paths which is formed by pin sealing surface and torque shoulder sealing surface.After representing the rough surface in symbolic form,the global finite element simulation of non-API needs to be completed firstly for the solution of the contact stress and area between pin sealing surface and torque shoulder sealing surface.On the basis of global finite element simulation solution,the partial finite element simulation solution can locate the region normal pressure maximum.For acquiring the critical amplification factor,the normal pressure maximum region needs to be self-affine magnified repeatedly until there appears a connected leak path.The leak rate prediction calculation model is established based on the percolation theory.According to actual conditions of gas well,tubing leak rate can be calculated.For dealing with the widely sustained casing pressure phenomenon from the gas production area,the fundamental goal of leak rate calculation model is the value prediction of sustained casing pressure.So on the basis of tubing leak rate prediction calculation model,the sustained casing pressure prediction calculation model is established.By considering the dynamic change,the correction of the tubing leakage rate calculation model is made.There proposed the dynamic sustained casing pressure model in different time space.At the end of the page,by measure the capacity of the gas sealing and the gas well,the correctness of sustained casing pressure model is verified.