Feasibility Study of the use of Local Clay as Mud Material in Oil Well Drilling in Nigeria

Abstract

Abstract The present consumption of bentonite clay in the drilling operations in Nigeria alone can reach over 100 thousand tons a year and all of it is imported. The large consumption and the high importation cost of this material lead to an attempt to find a local substitute which can save a huge amount of hard currency that otherwise would be spent on importing. This work focuses on the possibility of the utilization of local clay minerals as a basic material for drilling fluids used to drill oil and gas wells. Two samples of local clay were collected from Ikpoba River and Ovia River all in Edo State, Nigeria. API specifications for acceptable drilling mud were the basis for evaluation of the local clay. The properties of mud prepared from the local mud were improved economically by adding some cheap and available materials to the prepared mud. It was observed that the mud settles out from the water very fast after mixing, so additives was added (10grams of barite) which resulted in the increase of the weight and specific gravity of the mud. The local clay has significantly high sand content in comparison to the imported bentonite (67%). It has also low viscosity in comparison to commercial bentonite. Mud viscosity of the local clay was enhancement by adding Carboxymethylcellulose (CMC) and Tannin. After adding 3g of CMC and 2g of Tannin the Plastic Viscosity (PV) and the Yield Point (YP) of Ovia and Ikpoba were found to be 10 and 12, 7 and 10 respectively which compare closely with that of the imported bentonite of 6 for PV and 13 for YP. These characteristics of the local clay make it a potential material for application as drilling fluid when subjected to enhancement by also locally available additives.