Where Do Drill Cuttings Go in Offshore Drilling?

Abstract In offshore drilling operations, most water-base mud (WBM) and synthetic-based mud (SBM)-associated cuttings are discharged to the seabed whenever feasible. Although SBM is less toxic and biodegrade in marine sediments faster than oil-base mud, discharge of SBM associated with cuttings is still an environmental concern. It is highly desirable to know where the drill cuttings go during and after offshore well drilling. This paper presents an analytical method to predict the transport and settling of drill cuttings in seawater. Starting from Newton’s second law of motion, a mathematical model has been developed in this study to predict the transport and settling of drill cuttings in seawater. It can forecast the location, configuration, and characteristics of cuttings piles in flowing seawater. Factors affecting the cuttings transport include water depth, current velocity, cuttings properties (size distribution, density, and sphericity), and water properties (density and viscosity). This mathematical model has been computerized. It provides a useful tool for predicting the characteristics of cuttings piles that can be used for evaluating the potential impact of drill cuttings on subsea environment.