Application of Organoclays in Oil-Based Drilling Fluids: A Review

[Image: see text] Organoclays (OCs), formed by surface modification of clay minerals using organic compounds, are typical additives for providing rheology for oil-based drilling fluids (OBDFs). There are different studies on the effect of OCs on the rheological properties of oil-based systems under high-pressure, high-temperature (HPHT) conditions, but finding new OCs as rheology control agents is attractive for drilling fluid engineers. This work reviews different OCs used in OBDFs, namely, organo-montmorillonite (OMMT), organo-sepiolite (OSEP), and organo-palygorskite (OPAL). Furthermore, the structure of OCs in OBDFs, their rheological properties, and the thermal stability of OCs were investigated. Besides, the role of fibrous and layered OCs in enhancing the rheological properties of OBDFs is illustrated. Finally, the synergistic use of different OCs to enhance the thermal stability and rheological properties of the OBDFs is presented. The study highlights research gaps and recommendations for research approaches and potential areas that need further investigation. The application of OCs in OBDFs is a wide field and has huge potential to be developed. The use of OCs in OBDFs will promote development in the oil and gas industry.