Nigeria

Drilling mud is an important element of the drilling processes. Any drilling mud must possess common properties that facilitate safe and satisfactory completion of the well. However, the importation of bentonite is very expensive and the consumption is very high, there is need to further the research on the use of local clay as drilling mud. Clay samples were collected from three locations in Ekit-State, Nigeria. Atterberg limit (plastic, liquid and shrinkage limit) and pH of the samples were determined using laboratory approach and compared with the API standard. The liquid limit of the clay samples range between 28.0% and 50%, while the plastic limit range between 19.2% and 22.8% and the plasticity index ranges between 8.8% and 27.5%. The pH value of the clay samples range between 5.5 and 6.0. It decreases after addition of both Na2CO3 and KOH, ranges between 4.0 and 4.5. The pH value before and after enhancement did not meet the API specification for acceptable drilling mud of 9.0. However, the clay samples from Papa and Isan-Ekiti which consist of montmorillonite minerals can be used as bentonite if its pH is enhanced