Automated Model-Based Optimization Design of Subsea Field Layout under Production and Flow Assurance Constraints




Mnasri, Hamdi

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Subsea explorations are a major contributor to the global energy balance. A lot of research has been put into action to enhance all aspects of this industry despite the complexity faced. Therefore, developing tools with reduced computational time efforts while maintaining high accuracy levels is a crucial engineering and scientific challenge to maintain such position. Presented in this dissertation is an autonomous model-based simulation and optimization approach intended to be deployed during the pre-Front-End-Engineering-Design (pre-FEED) study phase of a subsea field development project. The proposed methodology is developed so subsea engineers use it as an asset to perform subsea field architecture design optimization. Based on a multi-objective optimization, experts can identify and select solutions satisfying pre-defined financial and technical targets. Additionally, the presented work is aimed to achieve tasks beyond its pre-FEED study utility. Specifically, deep-dive analysis is enabled to deal with real-time production system properties tracking, health monitoring and integrity assessment via model’s self-adaptation routines. By integration of different reduced-order physics-based models, a digital twin for a subsea production system is created. Hence, low-dimensional models have been developed to describe several aspects of a subsea system. A crucial part of the developed platform is illustrated via a multiphase flow reduced order model. A model developed as a steady-state multiphase mechanistic model in series with a dissipative distributed single-phase transient model, coupled via estimation of equivalent fluid properties. Additionally, flow assurance and structural integrity are serious issues within the subsea industry. A contribution to the presented matter, a data-driven parameter varying corrosion rate prediction model is presented as an amelioration of the existing prediction packages. Integrating the developed models along with several other reduced-order models within a hybrid optimization process, optimal layout scheme of a subsea field under production and flow assurance constraints can be determined. A digital twin of a subsea production system has been developed to mimic the operating process of a complete subsea production field starting from a newly discovered reservoir and ending at a terminal, thus, used as a virtual simulation environment of a subsea field overall life cycle within all compartment: upstream, mid-stream and downstream.



Multiphase Flow, Corrosion, Flow Assurance, Subsea Layout Optimization, Reduced-order Modeling


Portions of this document appear in: Hamdi Mnasri, Taoufik Wassar, Matthew A. Franchek, and Egidio (Ed) Marotta. "Data-Driven Modeling of Carbon Dioxide Corrosion for Integrity Management Application." SPE Prod & Oper 34 (2019): 667–677.