OTC 21587--Asphaltene Management in GOM DW Subsea Development

摘要

The asphaltene management philosophy for Chevron’s Blind Faith subsea development has evolved during the project and operations phases to incorporate additional experimental data, modeling results, and field observations. Initially, the project was designed with the philosophy of asphaltene mitigation via downhole injection of dispersants. After start up, operations identified the opportunity to halt asphaltene dispersant injection to wells operating outside of the asphaltene onset pressure (AOP). Based on field data analysis - both pigging returns & temperature sensors drift relative to model predictions - it was established that the asphaltene instability trend, ASIST, (Wang and Buckley, 2001; Buckley et al, 2006; Creek et al, 2009) model provides the most accurate representation of the asphaltene tendencies for the Blind Faith produced fluids, and its predictions are currently used to manage asphaltenes. The chemical cost per barrel for the field was reduced by approximately 25% due to the reduction in asphaltene dispersant consumption. During the second half of 2010, the operating conditions for some of the wells reached the predicted onset of asphaltene precipitation. Drifting of subsea temperature sensor, plugging of level bridles on topsides vessels, and accumulation in strainers occurred as a result, providing insight into the lack of effectiveness of asphaltene dispersants to mitigate these operational issues.