Using Microemulsion Technology to Remove Oil-based Mud in Wellbore Displacement and Remediation Applications

Abstract

Abstract Formation damage is a by-product of the drilling, completion, and production process and can be attributed to many factors. In openhole (OH) and cased-hole (CH) wells, hydrocarbon flow may be impeded by various damaging mechanisms caused by drilling and completion fluids, in-situ emulsions, water block, organic deposition, and oily debris left downhole. Microemulsion fluids have been successfully developed to effectively resolve the persistent problem of near-wellbore damage. The physical-chemical properties of these microemulsion systems include high oil solubilization, high diffusion coefficients through porous media, and the reduction of interfacial tension between organic and aqueous phases to near zero, making them excellent candidates for removing formation damage. The chemistry of microemulsion fluids make these systems excellent choices for superior synthetic or oil-based mud (S/OBM) displacements in casing and for OBM filter cake cleanup in openhole completion applications. Formulations have also been developed for casedhole perforation applications as well as post-perforation remediation treatments to remove the formation damage around the perforation or fracture zones. This paper presents a technical overview of microemulsion technology and a review of the test protocol used to qualify treatment solution designs for S/OBM displacement/cleanup and removal of formation damage in openhole and casedhole wells. Challenges and results from numerous field applications are presented that demonstrate the efficiency of microemulsion fluids for removing S/OBM debris and filter cakes, reducing near-wellbore damage and improving well productivity.