Vermiculite as an Anti-Sag Additive for Water-Based Drilling Fluids

Barite is widely used as a weighing material since it has several advantages such as high specific gravity, readily accessible, and environmentally benign. Even though, several difficulties with barite particle settling particularly at high-pressure high-temperature drilling operations and removal efficiency necessitate further investigation. The utilization of magnesium-aluminum-iron silicate (vermiculite) with its ecofriendly effect was studied in this work as an additive for improving the drilling fluid characteristics. Variable concentration of vermiculite was added to the water-based mud (WBM) to address the static and dynamic sag tendencies at 250 and 120 °F, respectively. Furthermore, the influence of vermiculite on rheological characteristics and filtration performance was studied under HPHT circumstances. The sagging experiments showed that adding 4 lb/bbl vermiculite improved the WBM stability properties by increasing the suspension capacity of barite particles. Also, this amount of vermiculite significantly enhanced the rheological characteristics as the plastic viscosity to yield point ratio (YP/PV) was increased from 1.6 to 2.5. The HPHT filtration showed that 4 lb/bbl decreased the filter cake thickness by 37.5% and reduced the filtrated volume by 39%.