Rheological properties and emulsion stability performance of invert emulsion drilling fluid using emulsifier derived from waste cooking oil

This study investigates the rheological properties and emulsion stability of invert emulsion drilling fluids using emulsifiers derived from waste cooking oil (FA-WCO) compared to commercial emulsifiers (CPE) and stearic acid (FA-SA). The objective is to develop an environmentally friendly and cost-effective emulsifier for high-pressure, high-temperature (HPHT) drilling conditions. The research involved preparing oil-based mud (OBM) samples at varying oil-water ratios (70/30, 80/20, 90/10) and temperatures (250°F and 400°F) and analyzing their performance using different emulsifiers. The findings revealed that the FA-WCO emulsifier exhibited comparable rheological behavior and emulsion stability to the CPE, with an optimal performance at an 80/20 oil-water ratio and 250°F. The plastic viscosity and yield point of FA-WCO were similar to those of CPE, and the emulsion stability was also closely matched. Stearic acid (FA-SA) showed higher plastic viscosity, yield point and gel strength but struggled with thermal stability at temperature more than 250°F. The study concludes that emulsifiers derived from waste cooking oil offer a sustainable and effective alternative for drilling operations, reducing environmental impact and promoting the recycling of waste materials. The results recommend the adoption of FA-WCO as a viable emulsifier in the oil and gas industry, particularly for HPHT drilling applications.