Experimental Study of Bio-Based Membrane Enhancers on Shale Through Osmotic Pressure Measurements

Abstract

Knowledge on shale formations which make up almost 70% of the wellbore section is crucial since drilling through shale formations are very problematic. Various mud configurations have been designed to curtail these challenges over the years. One of the approaches in solving this challenge is designing optimum membrane efficient water-based drilling fluids capable of generating high osmotic pressures in shales. A set of integrated experiments have been conducted on selected bio-based plants containing saponin responsible for bio-plants surfactant acting property. The crude extracts containing saponins were used to design a water-based mud and deployed in a series of pore pressure transmission inhibition studies through measurements of membrane efficiency, wettability, and zeta potential analysis measurements. Results indicated that the bio-surfactants can create the much needed high osmotic pressure in shales leading to significantly improved membrane efficiency of the shale of over 80%. The results confirmed the leaky nature of shales as semipermeable membranes and membrane efficiency was found possible to be a function of the saponin concentration. Membrane efficiencies in shales were found to be low with high-permeability shales not showing membrane efficiency at all. Further analysis of the data showed that the flux of ions is a function of the ionic radii, shale permeability, and the cation exchange capacity of the shale. Stability of the shale was sustained to a larger extent by the reduction the drilling fluid water activity ability in creating a high osmotic pressure in shales