Development of a Chemical Treatment for the Management of Wellbore Tar Adhesion

摘要

Incursion of subterranean tar into the wellbore during and/or after drilling has the potential to result in a variety of problems.If the tar is soft and deformable,it may'refill'the wellbore and require additional drilling time and casing operations.An additional problem is adhesion or accretion of the tar directly onto the drillstring or bottom-hole-assembly (BHA).Such fouling of the drillstring/BHA often requires unplanned tripping to physically remove the adhered tar.It is also conceivable that the tar-related problems may ultimately result in the hole being plugged and abandoned.For these reasons,an approach has been developed to(1)emulate the reported wellbore accretion,and(2)develop lab-based approaches to help minimize/reverse the tar adhesion.