Comparison of Aerated Fluids/Foam Drilling Hydraulics Simulators Against Field Data

Abstract

Abstract The application of light-weight compressible fluids in deep-water offshore operations will soon be a reality. An important factor in the design, accompanying and post-analysis of such a project will be the prediction of reliable downhole pressures, which are expressed in terms of Equivalent Circulating Densities (ECDs). Obtaining dependable ECDs for aerated (gasified) fluids and foam is more difficult than for single-phase fluids, since in the former ones the drilling mud has a gas phase in its composition. Drilling hydraulics simulators can be an important tool in the prediction and analysis of ECDs. There are both steady state and transient computer simulators available for ECD prediction, however their results need verification for different scenarios and different liquid/gas combinations. In an effort to determine the most suitable simulator program for different well geometries, light-weight fluids and a range of liquid/gas combinations, real-time measured field data were analyzed and compared to bottom-hole pressures predicted by four different drilling hydraulics simulators. Additionally, the principle aspects of these drilling hydraulics simulators were compared based on the following characteristics: accuracy, user interface, numerical stability, and convergence.