Effects of Different Types of Weighting Agents on the Performance of Oil Base Drilling Fluids

The success of oil and gas well drilling depends to a large extent on the performance of drilling fluid, whichis greatly affectedby the weighting agent used. A drilling fluid weighted with different weighting agents will perform quite differently during drilling. In laboratory studies, a micron powder barite, a conventional barite and a micro powder manganese mineral used in formulating drilling fluid samples were analyzed for their particle sizes. The viscosity, API filter loss and friction coefficient of mud cake of the three drilling fluids were measured to study the effects of weighting agent on the performance of drilling fluid. It was shown that the micron powder barite had the finest particle sizes and the drilling fluid formulated with this barite had the highest viscosity, and mud cake of poor quality was formed. Drilling fluid formulated with the conventional barite had poor lubricity. The manganese mineral had bigger particle sizes and wider particle size distribution.A drilling fluid formulated with the manganese mineral and conventional barite had performance that was obviously improved.