Abstract
For high-density fluids, achieving the right fluid formula with the right fluid rheology is difficult since excessive heat, dehydration, and solid loading can deteriorate mud properties. Addition of weighting materials such as barite is needed to achieve the desired density to overbalance the well and avoid any possible flow from the formation. However, maintaining a high volume of solid content for barite particles in suspension might be challenging, especially for extended period. The separation of barite from the mud can lead to undesirable density fluctuation as drilling fluid is being circulated throughout the hole. This phenomenon may lead to potential well control incidents and stuck pipes.
The objective of this study is to design new high-density water-based drilling fluids with lower solid content and mitigate the issues arising due to drilling with high-density drilling fluids. The experimental work in this paper involved rheological properties, thermal stability, HT/HP filtration, and static sagging (vertical and deviated) of 120 pcf and 150 pcf high density water-based drilling fluids. The paper will highlight field cases of proper maintenance program on fluid properties to mitigate any potential well control incidents and will recommend fluids formulation properties when using high solid content water-based fluids.
