Integrated production modeling to assess the effect of subsea water separation

Abstract

Conventional field development design and planning based on isolated work from the reservoir and the production engineering department can not capture the interaction between the two disciplines for long term production forecast. Particularly, in offshore development, it is imperative to integrate the two engineering domains in the qualification of a potential subsea technology because any new element added into the subsea architecture will impact the performance of the entire system. This thesis establishes models that integrate the reservoir and the subsea production system as a whole. The integrated approach is then applied to quantify the effect of a specific subsea technology: subsea water separation. In this work, four integrated production models are presented and compared. Two of them are fully implicitly integrated models while the other two are coupled simulations between a reservoir simulator and a pipeline simulator. Numerical examples show that, compared to loosely-coupled simulations, implicitly integrated models are in general favorable in terms of computation time and stability. Three case studies are presented to demonstrate the application of the two implicitly integrated models for evaluating the effect of subsea water separation on three quantitative indicators: NPV, recovery rate, and wax-free index. Results show that subsea water separation has the potential to increase NPV and recovery for a clustered well system by increasing production rates and reducing injection requirements. However, its application on individual satellite producers has limited advantages because of the negative interference among wells. What’s more, when applying subsea water separation, there will be a higher risk of wax deposition for a satellite well system than for a clustered well system