Effect of Micro-Sized Colemanite on the Rheological Properties of the Water Based Drilling Fluid

Abstract

Drilling mud have been the subject of constant study since they are the most costly item of oil exploration. Recently, the several additives have been added to improve the rheological properties of the drilling mud. In this study, a water based drilling mud that is (1, 2, 3, 4 and 5) (% w/v) of colemanite (Ca2B6O11.5H2O), which is a calcium borate group mineral in the particle size of 100 μm subscale, was prepared for this drilling mud. The rheological properties such as plastic viscosity (PV), apparent viscosity (AV), gel strength, water loss and cake thickness of the obtained drilling muds were analyzed in detail using Fann Viscometer and American Petroleum Institute (API) testing equipment. As a result of the study, it was found that the added colemanite had a positive effect on the rheological properties of the drilling mud. When the analysis results of the drilling muds obtained at different ratios of colemanite addition are compared with each other, it is found that 4% of colemanite-added drilling mud has the best properties (excluding gel strength). The water-based drilling mud prepared by adding colemanite has 30.4% cP of plastic viscosity; 63.6% cP of apparent viscosity; 140% of rupture point; gel strength (10-sec and 10-min) values compared to the water based drilling muds prepared without any addition was positively affected.