Abstract

The consumption of bentonite clay in Nigeria has continued to increase as drilling activities keep increasing. Huge amount is spent for the importation of this clay from overseas. In this work, water based muds were formulated from the local bentonite clay and characterized for application in drilling operations. The bentonite clay (calcium based) was beneficiated with soda ash (Na2CO3) for its conversion to sodium based bentonite through ion exchange. Five samples of bentonite muds (A-E) were prepared using 350 ml distilled water and additives comprising of 10g barite and polyanionic cellulose (PAC) of varying amount (1-2.5g). The rheological properties of clay were determined and compared with commercial bentonite. The results of the apparent viscosity were 3.5-24.5 cP, yield point 3.0-23.0 lbf/100ft 2 , plastic viscosity were 2.0-12.0 cP and the gel strength 1.0-4.0 lbf/100ft 2 . The yield point to plastic viscosity ratio and plastic viscosity of the samples without additives are within the specified limits of oil company material association (OCMA) standard. Fika bentonite clay exhibits good rheological properties that could compete favorably with that of commercial bentonite when beneficiated with soda ash, barite and polyanionic cellulose. Hence, drilling fluid could be formulated from Fika clay for application in drilling operations.