EXPERIMENTAL STUDY ON MEMBRANE EFFICIENCY OF SHALES THROUGH PORE PRESSURE TRANSMISSION MEASUREMENTS.

Membrane efficiency (ME) in shale drilling particularly with water-based drilling fluids (WBDFs) has gained strong research attention due to the impact of oil-based drilling fluids on the environment and the legal challenges it presents. A suite of experiments has been conducted on selected bio-based plants containing surfactant property. These surfactants are used to formulate water-based drilling fluids and their performances tested through a pore pressure transmission test. Results indicated that the type of membrane enhancer used in WBDFs affects the membrane efficiency of the shale-mud system. It also revealed that the saponin amount in the crude bio-surfactant used for the mud formulation correlates directly with the membrane efficiency and indirectly with the crude bio-surfactants critical micelle concentration (CMC). Crude bio-surfactant particle size was found to have an impact on membrane efficiency at low permeabilities than at high permeabilities. Depending on the bio-surfactant used membrane efficiencies were improved over several degree of percentages with the least improvement of ۳۵%.

Keywords:

Shale , Bio-Muds , Shale Instability , Pore Pressure , CMC