Preventing barite sagging using new synthetic layered silicate in HP/HT water-based mud

Barite is one of evaluated weighting materials in oil and gas drilling operations because it is inexpensive, and it can rise the mud density up to 19 lb/gal. However, barite has these advantages, but it has the problems related to settling of its particles known as barite sagging. The objective of this study is to add a different concentration of synthetic layered silicate (SLS) to the field formula of WBM to prevent the sagging of barite in both static and dynamic condition at 250°F. In addition, the effect of SLS on rheology will be conducted. Moreover, high pressure high temperature (HPHT) filtration test also performed to characterize the filter cake thickness and filtration volume. The sagging experiments showed that adding 0.75 lb/bbl of SLS reduced the sag factor from 0.569 to 0.502 and from 0.58 to 0.51 in vertical and 45° inclined respectively. For the dynamic sag, the viscometer sag shoe test (VSST) decreased from 2.3 lb/gal to 0.17 lb/gal after adding 0.75 lb/bbl of (SLS). Furthermore, the (YP/PV) was increased from 0.94 to 1.25 after adding 0.75 lb/bbl of (SLS). The HP/HT filtration loss decreased by 20% with decrease in the filter cake thickness.