Mineralogy and rheological properties of some Egyptian bentonite for drilling fluids

The selection of drilling fluid is considering main factor for oil and natural gas well drilling processes success. Drilling fluids play important role in carrying and suspending drilling cuttings, high rates of penetration, maximizing bit life, minimizing fluid loss into the formation and stability of the formation. In this study, clays collected from claystone quarries in Gabal Hamza - um Qumar north Cairo-Ismailia Desert Road, Egypt for its application as water base drilling mud. These clays consist mainly of montmorillonite in addition to kaolinite as indicated by X-ray diffraction (XRD) and scanning electron microscope (SEM). The rheological and filtration properties of drilling fluids were designed with different types of additives such as Caustic soda, CarboxiMethyl Cellulose (CMC) and polyanionic cellulose polymer (PACR). Although designed different types of polymer compositions did not meet the required rheological and filtrate properties; the addition of Caustic soda, CarboxiMethyl Cellulose (CMC) and polyanionic cellulose polymer (PACR) gave better rheological and filtrate properties of bentonite suitable for drilling medium depth wells.