Influence of pressure on the gel strength and on the solid-like behavior for an inverted emulsion drilling fluid

Abstract

Oil and gas exploration and production in deep and ultra-deep wells located in high pressure and high temperature zones (HP/HT) are increasing considerably to meet global energy demands. Exploration in HP/HT zones presents several challenges to the performance of drilling fluids to maintain wellbore stability during the drilling process. The rheological characterization of drilling fluids has been extensively investigated through experiments at atmospheric pressure; however, there are many open questions concerning high-pressure conditions. This work aims to perform a rheological characterization of inverted emulsion drilling fluid with measurements performed under a wide high-pressure range. The experiments were carried out in a rheometer coupled to the pressure cell system. The results show that the impact of the pressure is more relevant in the solid than in the liquid-like regime. Not only the viscosity, storage modulus, and yield stress tend to increase under pressure but also the material yield strain. The higher the applied pressure, the greater is the deformation that the material withstands in the solid regime. These findings can bring relevant information to the oil and gas field since the knowledge of the material gel strength under high pressures is fundamental for the drilling operation.