Cuttings Lifting Coefficient Model: A Criteria for Cuttings Lifting and Hole Cleaning Quality of Mud in Drilling Optimization

Abstract

In this study, the hole cleaning qualities of mud samples formulated with tigernut derivatives – starch and fibre – as additives were determined by adding drill cuttings as impurities and evaluating the Carrying Capacity Index (CCI) as well as Transport Index (TI) of the muds. Results of the analysis conducted for the mud properties showed that all the different mud properties but the pH of the mud evaluated of mud samples B, C1, C2, and C3 were slightly higher (albeit within the recommended values) than those of the control (standard) mud sample A. Using the results obtained from mud properties analysis and drilling operations data for the evaluation of the hole cleaning qualities, the following new expressions for optimum cuttings lifting ability (β) and cuttings lifting coefficient (β1), which gives criteria for cutting lifting in a wellbore were developed: β1 = 0.11519 [(1 − Cf)]−1(dp)−2.014. The higher the value of β1 greater than one, the better the hole cleaning ability of the mud and the lower the mud flowrate needed to achieve better hole cleaning for a given cutting particle size.