Benchmark of Erosion Criteria in a Deepwater Development

Ultra-Deep water projects worldwide and particularly in Brazil are characterized by high capital investment costs. This fact generated the need to explore opportunities to improve project value, even though the project was still during visualization phase. One of the identified opportunities was related to API 14E erosion standard application, as it is considered to be conservative for estimating the erosional limits in oil and gas applications. There are additional industry practices that are widely used in industry that provide more accurate estimations of erosional velocity limits. If these values are increased, there is an opportunity to enhance project value as it would allow a reduction of the required number of wells and production line / riser diameters. If the API erosional limit is considered in the project, the wells would produce at lower rate than reservoir potential, which would lead to an increase in the number of development wells. Based on the significant perforation cost of deepwater wells, the increase on this number would be reflected in the total development Capex, eroding the project value. This paper describes the work performed in order to better understand the possible erosion phenomena in the production system due to the high fluid velocities in a gas condensate field and to determine the maximum allowable gas rate with different erosional models (API 14E and Tulsa SPPS). The proposed methodology provides the opportunity to enhance project value by predicting erosional rate limits via SPPS, as the current applied standard was considered to be conservative in erosional rate prediction. If confirmed as feasible, significant cost reduction could be achieved in the project as the individual gas well production could be increased by the reduction of the number of wells; estimated well cost reduction is around 400 MMUSD per well, plus associated subsea production system.