Formation fracture pressure calculation in high temperatures wells

Correct prediction of formation fracture pressure is the primary precondition for safe and speedy drilling. Many studies on this subject have been performed and many methods for formation fracture pressure prediction have been put forward. But few of them consider the influence of temperature on fracture pressure in high temperature wells. A new coupled temperature model for fracture pressure calculation by analyzing formation temperature and stresses change due to heat exchange between circulating drilling fluid and formation is established. The effect of temperature on fracture pressure is quantitatively analyzed. A calculation example is presented and the results show that the new model can greatly improve the accuracy of fracture pressure prediction.