Development of Three-Layer Model and Numerical Simulation for Cuttings Transport in Horizontal Foam Drilling

Abstract

Foam drilling has grown tremendously in the last few years. Foam is often used as a circulating fluid in underbalanced drilling operations (i.e. to keep the pressure of the drilling fluid less than the pressure of the formation fluid). Foam drilling has been shown to provide significant advantages, such as higher penetration rate, effective cuttings transport, less formation damage, etc. However, although, a few studies have been conducted on vertical wellbores, there is little detailed published information related to its use in horizontal wellbores. In this study, the cuttings behavior in horizontal foam drilling was numerically investigated. First of all, the experimental results of foam rheology and particle settling test were shown. Experimental results showed that the foam behaves like power law fluid and foam volumetric quality has a major impact on the settling phenomena. The next, a three layer model was developed to predict and interpret the cutting transport behavior in horizontal foam drilling. This model consists of a three-layer configuration, i.e. stationary bed of drilled cuttings at the bottom; a moving bed above it; and a heterogeneous suspension layer at the top. This model is based on conservation laws of mass and linear momentum as well as on constitutive relations that describe the interactions between each phase and the walls. The model was solved numerically to predict the cuttings bed height, pressure drop at different foam flow rates under several conditions. Furthermore, numerical simulations were carried out in order to investigate some factors affecting the cutting transport in horizontal foam drilling. The results of numerical simulation are presented.