Research & application of the drilling fluid for water sensitive stratum

Abstract

Modern geological drilling often applied small diameter wire line coring, due to the annular gap between borehole wall and drill rod is very small, so in the drilling of water sensitive stratums, cuttings prone to clogging the annulus, and then result in high pump pressure which damage hole wall and cause downhole accidents. According to rocky and mineral ingredient, water sensitive stratums can be classified: hydrous corrosion, hydrous swelling and hydrous peeling, etc. In the drilling construction of complex stratums, how to choose and use the drilling fluid is very important. This paper analyzes and summarizes two of the most complex and difficult projects which had been encountered in recent years, the stratums were hydrous swelling chlorite stratum and hydrous peeling carbonaceous slate. Dealing with this type of water sensitive stratum, in conjunction with the suitable drilling process, how to select, use and maintain the performance of drilling fluid have been discussed and summarized. © 2014 Published by Elsevier Ltd.