The development of Offshore Oil and Gas Production Systems demands a multi-disciplinary team to investigate a multitude of design uncertainties extending from the reservoir to the production facilities, and commodity product sales. The generation of concept options usually follows a linear and technically oriented process, where each specialized discipline determines the technical requirements and boundary conditions to the next discipline. The process may be repeated as new information becomes available, and some design uncertainties are progressively reduced, as most of key design parameters are stochastic and non-deterministic. This methodology may vary between Oil Companies regarding the logical sequence, accuracy range and concept coverage, but is strongly driven by the Company's culture and by industrial capacity available in each region.
Due to limitations of time and availability of costly multi-disciplinary specialized resources, the generation of field development concept options is often focused primarily on generating concepts considering the highest technological maturity and the lowest Capital Expenditure (CAPEX). Following this approach, the generation of ranked concept options with a focus on the Net Present Value (NPV) is usually performed on a limited workable number of options. The NPV check is a project finance tool to assess and rank the concepts generated at the end of the engineering process. Further design phase iterations tend towards these same options, resulting in either slow and incremental improvement, or worse through propagation of the initial uncertainties, inadequate facilities design and reduced project reward.
On a process digitization perspective, an integrated and automated design computational model enables specialized disciplines to probe and visualize the concept search space, including lower maturity concepts with potentially higher NPV reward. Automation accelerates the design process, allowing the necessary time to focus efforts either on maturing concepts from an earlier phase, or on minimizing uncertainty in propagation, by reconsidering full concept search space in subsequent design phase iterations, ensuring more adequate facilities design.
The objective of this paper is to present the results of an integrated design approach applying a computationally developed model, focusing on automating the process of offshore full field concept generation and ranking during early project phases to fetch optimized designs. Based on the use of the computational model, a case study was developed, highlighting the sensitivity analysis of CAPEX, OPEX (Operational Expenditures) and NPV, by varying specific parameters in typical subsea production system architectures. The hypothetical scenario is representative of the ultra-deepwater environment in the Brazilian Pre-Salt.