Evaluation of the Rheological Properties of Raphia Sese Oil Based Mud (Ester Oil) for Oil Field Drilling Applications

Purpose: The environmental challenges posed by oil-based drilling fluids along with legislation associated with their use have necessitated the development of synthetic organic liquids that are able to both meet the technical and environmental requirements of the industry. In this regard, an environmentally friendly vegetable oil-based mud from Raphia Sese oil (ester oil) was formulated and its rheological properties and economics abilities analyzed. Methodology: The rheological properties of the mud such as plastic viscosity, yield point, flow index, apparent viscosity, consistency index, dial readings, density, and pH were evaluated at unaged conditions from 80 oF to 200 oF. Findings: The results showed that Raphia sese oil base mud was compatible with the conventional oilfield additives. Though its mud naturally recorded a low pH (8.3) due to the low pH of the Raphia sese oil (5.53), with improved extraction process and with the addition of pH additives, this could be enhanced. When compared with diesel-based mud, the Raphia sese based oil mud recorded higher density values and promising rheological properties. Though the initial cost of conditioning Raphia sese oil for mud formulation purposes was high, it was offset by its disposal cost as compared to that of diesel oil (saves about 34% the cost of using diesel). Recommendation: From the findings, it is recommended that the recovery process of the Raphia sese oil as well as its thermal oxidation stability should be improved. Again, higher thermal conditioning testing must be done to ascertain the stability of the Raphia sese oil at higher temperatures. Also, the Congolese nation could consider the domestication of the Raphia sese palm to increase the production of its oil and the nation could go into the improved cultivation to promote local content and participation policy of the oil.