A simplified computer model for determination of cuttings conscentration and wellbore cleaning

Abstract

Gasbarri, S., & Wills, V. C. (2014, May 21). Plugging of cuttings in the wellbore is a common problem during drilling processes. Some authors have analyzed settling or slip velocity of particles in a liquid both analytically and experimentally. The concentration of cuttings throughout the well has been also analyzed. It has been proven that numerical models have the potential to help predict the performance of the cuttings concentration for solving this problem. A computer model for determining the cuttings concentration for the different processes applied during wellbore drilling is presented. It is a useful tool for the drilling engineer to predict and analyze the drilled cuttings transport to assure efficient wellbore cleaning during operations. The model is based on central difference, and non-Newtonian power low fluids can be used. The effect of the cuttings interaction for different concentration in the settling velocity was determined experimentally. The model was designed to allow the user to calculate the cuttings bed formation, determine whether the bed remains stationary or build ups and analyze the position of the cuttings bed formed and the height of the cuttings bed layer. Using a typical case study, the wellbore cuttings concentration and the height of the cutting bed are shown for the different processes; i.e. during hole-cleaning and shut down. The effect of operating parameters, wellbore geometry, non-Newtonian fluid parameters and cutting characteristics was analyzed. This computer model is a helpful tool to predict stuck problems and speed up wellbore cleaning processes.