The Effect of Weight Material Type on Barite Sag Tendency

Abstract

Settling of weight materials is a phenomenon that occurs in high-pressure formations where a high mud weight is needed. Barite sag is roughly defined as the change in density due the settling of weight materials that observed when circulating bottoms up following operations such as tripping pipe where the mud has not been circulating for an extended period of time. This may lead to problems such as lost circulation, well control difficulties, poor cement jobs, and stuck pipe in oil industry. In deviated wells, the settling distance to the lower side of the wall is small in comparison to vertical wells. This leads to rapid generation of solids beds and consequently, sag problems are particularly severe in deviated wells. The authors present the settling rate of different weight materials in muds with mathematical method. Furthermore, it investigates the effect of weight material type and hindered settling factor on settling rate. Moreover, the type of weight materials for barite sag management is recommended.