Combining SBM Modeling and Drilling Data to Elucidate GOM Well Problems

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis paper discusses a field-applicable wellbore hydraulics simulator for modeling cement displacement using SBM (synthetic-based mud) inside casing strings, and calculating ECD (equivalent circulating density) and SPP (standpipe pressure) while drilling with compressible mud. The paper shows how drilling data and model results can be used collaboratively to improve the understanding and solution of well problems. The spreadsheet-based simulator consists of readily available models designed to describe the behavior of SBM under typical conditions encountered in deepwater GOM (Gulf of Mexico) operations. The algorithms account for water depth, pressure, temperature, mud composition, viscosity, wellbore size, and cuttings loading throughout the wellbore.Field tests in straight holes where PWD (pressurewhile-drilling) tools were run show good results. Typical errors between calculated and measured ECD were ~1%. In the casing cementing study, measured cement displacement volume to bump the plug compared favorably with model predictions, after proper considerations of compressibility. Applications to high-angle wells require some adjustments.