For calculation of density of drilling fluid in down-hole HTHP environment, a simplified calculation method is presented, which combines the composite model and empirical model methods with the actual on-site drilling operation. The method solves the liquid density calculation in drilling fluid composition by considering the liquid water and the liquid oil density changing with temperature and pressure as well as taking into account the components of drilling fluids. Experiment verification with a certain typical water-based drilling fluid and oil-based drilling fluid shows that the method can not only meet the calculation precision demand of engineering but also provide an easy calculation means of high operability.

drilling fluid density  /  composite model  /  empirical model  /  simple calculation method