Effect of temperature variation on the accurate prediction of bottom-hole pressure in well drilling

Abstract

ABSTRACT Knowing the effects of different parameters on the drilling fluid is an essential part of a successful and safe drilling operation. High pressure and high temperature conditions have opposing effects on the fluid density which has an important effect on the bottom-hole pressure. So for estimating precise bottom-hole pressure, it is essential to take into account these opposite effects on drilling fluid compression or expansion. In this study, Bingham-plastic model is considered as drilling fluid to simulate drilling operation and develop temperature and pressure distribution through the wellbore. The effects of variation in drilling fluid flow rate, drilling fluid specific heat and inlet mud temperature are explored and discussed for an oil-based mud. Also, the effects of frictional pressure loss, pressure loss in the drill bit and, drill string rotation are considered as internal heat sources in the wellbore. Results show that thermal interaction is required for accurate prediction of the bottom-hole pressure. Variations of different parameters change temperature distribution in the wellbore which consequently changes the bottom-hole pressure. The results show that considering the variation of rheological properties, bottom-hole pressure prediction may change as much as 685 psi (about 2.30%) which is considerable. Model predictions were compared with the field data for validation of the model.