Verification of the OOC mud and produced water discharge model using lab-scale plume behaviour experiments

This paper describes comparisons of predictions by the Offshore Operators Committee (OOC) Mud and Produced Water Discharge Model with published data on experimental laboratory-scale observations of plume behavior in flumes, towing tanks, and wind tunnels. The ability of the OOC Model to predict the plume characteristics observed in numerous individual tests of plume behavior covering a wide range of discharge conditions was examined. Data are provided summarizing the predictive ability of the model for all tests. The dimensionless parameters describing the physical characteristics of the plumes were within the range expected for typical Gulf of Mexico produced water and drilling fluid discharges for most of the comparisons. The model was in good to excellent agreement with measurements of plume behavior under most discharge conditions. The model was less accurate for those experimental cases where extreme plume bending occurred. It is believed that turbulence caused by the discharge pipe itself influenced the behavior of these extreme-bending plumes. The predicted density of solids accumulation on the bottom of a towing tank, a lab-scale analogy of the seabed accumulation of drilling solids, was within a factor of two of experimental observations. Excluding the three simulations of extreme bending plumes, the model showed no systematic trend towards either under- or over-estimation of any parameter examined. This suggests that experimental errors or biases may have contributed to observed differences between predictions and observations. The results of the validation testing described in this report increases confidence in the use of OOC Model predictions as an alternative to the difficult and expensive process of performing field measurements for every practical discharge situation. (C) 2003 Elsevier Ltd. All rights reserved.