Statistical Relationship of Drilled Solid Concentration on Drilling Mud Rheology

Abstract

Drilled solid is a continuous contaminant in drilling mud during drilling operation. The purpose of this study is to evaluate the statistical correlation of drilled solid concentration on mud rheology. A Spearman’s correlation was used to determine the relationship between 31 mud rheology data and the drilled solid concentration data from North Kuwait Field. Four rheological models were used to compare the rheological behaviour of the drilled solid-laden drilling fluid which were Bingham Plastic, Power Law, Herschel-Bulkley and Robertson-Stiff Model. Results showed that a positive monotonic relationship was observed between all drilled solid concentration and mud rheology parameters. An excessive relationship was observed between drilled solid concentration and mud density with a Spearman coefficient (ρ) of 0.942. Other mud rheology parameters such as plastic viscosity, yield point and gel strength show a significant (high) relationship with a spearman coefficient (ρ) in between 0.833 and 0.704. Flow curves of the drilled solid-laden drilling fluids used in this study can be well depicted by the Herschel-Bulkley and Robertson-Stiff Model. These results are not only support the justifiable attention given to address drilled solid impact to the mud rheology, but they also proposed a statistically approach in preparing data for analysis.