Analysis of Barite Segregation in Deviated Wells by New Apparatus

Barite Sag is an oilfield term used to describe significant density variations while circulating bottoms up following operations such as tripping pipe where the drilling fluid 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. Therefore, the barite sag investigation is important in drilling industry for cost reduction due to less drilling problems. Sag problems are particularly severe in deviated wells. Since in high pressure deviated wells torque and drag is high in comparison to vertical wells, oil based muds are used for reduction of friction factor. Preparing an oil based drilling fluid with high mud weight is impossible for overcoming pore pressure, hence water based mud is used inevitably. In this paper, after setting up an experimental apparatus the amount of barite sag in static conditions is quantified at various inclinations and critical range for inclination is determined. Furthermore, effect of the mud weight is investigated in the determined range of angles.

Keywords:

Settling , Barite sag , Weight material , Inclination , Density