Modelling the effect of mudstone cuttings on rheological properties of KCl/Polymer water-based drilling fluid

摘要

Drill cuttings unavoidably enter the annulus and affect the rheology of the drilling fluid in the process of drilling. The rheological properties of drilling fluids containing varying particle size and cuttings amounts were measured by using a rotational viscometer equipped with a widened gap. An algorithm based on Tikhonov regularization was proposed to transform the viscometry data into flow curves. Validity and availability of the presented algorithm were investigated by applying the algorithm to the base drilling fluid (without cuttings). Results showed that the flow curves of the cuttings-laden KCl/Polymer drilling fluids used in this study can be well depicted by the Herschel-Bulkley (H-B) model. Based on the rheological parameters obtained from curve fitting, the empirical correlations for the flow behavior index and the consistency coefficient were proposed. The consistency coefficient increases with the increase of cuttings amounts and the reduction of cuttings size. While the flow behavior index decreases with the increase of cuttings amounts and the reduction of the cuttings size. The proposed rheology determination approach in this study could give an orientative performance for cuttings-laden drilling fluids.