Here's how compressibility and temperature affect bottom-hole mud pressure

This study presents graphical results showing how bottom-hole pressures and mud weights vary with depth for various oil and water muds and different temperature profiles. The model can be adjusted to handle not only constant temperature gradients, but any arbitrary temperature profile. In particular, a wellbore thermal simulator code has been used to generate circulating mud temperature profiles. Results from this model have been used to predict hydrostatic bottom-hole pressures for muds containing various amounts of oil, water, chlorides, and solids. 11 refs.