Effect of P-rho-T behavior of water muds on static pressures during deep well drilling

In this study, an empirical model is proposed to describe the P-rho-T behavior of water-based drilling muds. An analytical method is described to estimate the static pressures in the mud columns having temperature linearly increasing with depth. Approximate thermal gradients under which constant mud density condition holds good are also discussed. Static pressures calculated for hot and deep wells show that the variations are significant enough to cause well control problems.