SUITABILITY OF NIGERIAN (WARSALE) BENTONITIC CLAY FOR OIL WELL DRILLING MUD FORMULATION

摘要

Nigerian oil and gas drilling operations are highly depended on the imported bentonite for use asdrilling fluid. The importation drains the nation's foreign reserve despite the fact that the country isequally blessed with huge deposit of this natural resource even though of inferior quality. This researchcharacterized the Warsale montmorillonite clay from Dikwa formation. The clay was beneficiated (wetand dry) using Na CO and the beneficiated drilling muds formulated. Drilling fluids formulated fromthe beneficiated clay did not possess the minimum rheological properties for use in oil and gas drillingoperations. However, an improvement in rheological and filtration properties was observed whenbeneficiated with Na CO and treated with CMC. The optimum values for plastic viscosity and gelstrength were obtained at 6-10wt Na CO concentrations. The fluid loss of muds from Warsalebentonite was improved by about 50 when treated with Carboxy-Methyl-Cellulose (CMC) and meetsthe API requirements. The pH and sand content of the muds also fall within the API standards. Therheological and filtration properties of the local clay were found to be inferior to the referenceWyoming bentonite due to low concentrations of smectites and high levels of contaminants in thecompositions of the local clays. However, this study shows that given the proper conditioning,beneficiated Warsale clay will give a good promise for drilling purposes at optimum sodium carbonateand additives concentrations.