Feasibility Study of Drill Cuttings Slip Velocity Estimation using BBO DTM-Pade’ Semi-analytical Technique

Abstract

The study reviewed the use of DTM-Pade’ approximation method of Basset–Boussinesq–Oseen equation (BBO) in predicting particle slip velocity. A hypothetical example is used in the study with three different diameters, 3,5 and 7mm, of spherical particle assumed to represent wide rang of drill cuttings’ sizes. In addition, the drilling fluid is assumed to be incompressible fluid in stationary mode. The Pade’ approximation (K=20, [8 8]) is used, based on literature, in calculating slip velocities through 2 seconds time span. It is concluded that this technique is a practical mean of particle slip velocity prediction at high Pad’ orders using Matlab for a short period of time, around (o.1 to 0.2 seconds). However, BBO equation application range such as, single particle fall in infinite incompressible fluid, small particle size rang (less than 3mm), low particle to fluid density ratio (higher than 0.38), limits its application in oil well drilling operations. Moreover, the necessity of more factors considerations in simulating drilling operations including Non-Newtonian fluids, wall effect, and wide range of irregular shaped drill cuttings densities and sizes urges for the use of generalized BBO equation. In drilling operations, concisely, drill cuttings are usually mixed in the wellbore annulus and for more reliable predictions the application of more sophisticated techniques such as Machine Learning (MA) and Artificial Intelligence (AI) become indispensable.