Based on two annular pressure buildup mechanisms, coupling of wellbore heat transfer and formation heat transfer and coupling of gas temperature and gas pressure, we build a calculation model for critical rate in deep high temperature high pressure( HT/HP) gas wells. It takes account of influence of gas well profile, string assembly and fluid properties. The model is solved with programm based on iterative method. Finally, it is applied to a deep HT/HP gas well in Tarim oilfield. Critical rate under several operational modes are calculated and they provide basis for optimum allocation in deep HT/HP gas wells.

A boundary element method (BEM) for Burton-Miller boundary integral equation is accelerated efficiently with Graphics Processing Units (GPUs).Conventional BEM formulations are reformulated so that they can be handled efficiently in GPU.Singularity extraction and local correction techniques are used to evaluate singular integrals,including strong-and hyper-singular ones.Numerical results show that:(1)The proposed method obtains unique and correct solutions at fictitious frequencies;(2)Accuracy of the method is almost the same as that of conventional BEM;(3)Computational time and memory consumptions of the proposed method are much lower than reported results.It shows that GPU-accelerated BEM based on Burton-Miller equation is a fast,efficient and simple method for medium-or large-scale acoustic problems in engineering.