Physiochemical Characterization of Bentonite Clays for Oil Well Drilling Fluids

چکیده مقاله

Bentonite, a well-known type of clay found abundantly in nature, is used in water-based drilling fluids. The functions of this clay widely used as the drilling mud are to remove cuttings from the drill hole to keep formation fluids from penetrating into the drilling mud, to lubricate and cool the bit, and to build an impervious filter cake on the wall of the drill hole to prevent the penetration of water from the drilling fluid into the formations and formation fluids from the drilling mud. Montmorillonite, the main constituent of bentonite, is a nano-structured nano-porous mineral made from 2:1 (three) layer alominosilicate with regular crystalline structure, is responsible for almost all properties and characteristics of bentonite. In this study, characteristics of nano-porous structure of four industrial grade bentonite samples namely, B1, B2, B3 and B4 were investigated to determine whether or not they can be used as suitable drilling mud. Instrumentally analyzed samples using XRD, XRF and BET analyses were tested by laboratory tests including moisture content, pH, swelling and sediment indices, surface area and cation exchange capacity as well in order to select the appropriate sample to be used as drilling mud. The physiochemical investigation of four samples reveals that there is bentonite clays are quite suitable for the development of water-based oil well drilling fluids.