An Investigation on the Optimal Definition of Projects Scope, Facilities Sizing and Design Life for Truly Sustainable Deepwater Field Development: Technical Aspects and Economic Considerations

Abstract

Notwithstanding the great technical changes that occurred in the offshore industry over the past decades, and the undeniable success of the subsea technologies, deepwater project sanction appears to remain rooted in traditional CAPEX minimization and NPV maximization. This paper investigates how decisions made by reservoir evaluation, and drilling and completion planning affect the design of subsea production systems and, in turn, the design of production hosts. Challenging the current approach to project framing and definition, practical alternatives are explored with a conceptual case study designed to test the ideas here presented. Deepwater production is expected to play a significant role in meeting the future oil and gas demand of the world. To do so, new fields need to be developed in challenging environmental conditions, and existing fields will undergo brownfield modifications to sustain acceptable production levels. OPEX will reflect the increasing costs for inspection, maintenance and repair. Rethinking the requirements of deepwater field development will help to define the proper size of the subsea and surface facilities, the optimal design life and the possible need for staged developments. A case study has been created to observe how changes in facility size, design life and development time-line (stages) result in changes to the overall subsea CAPEX and OPEX. These costs have been discussed with respect to drilling and completion costs and host facilities costs to identify possible opportunities and criticalities. Given the possibility of protracted low oil price environment, new ways of developing deepwater fields is worth considering. Greater integration of the various disciplines (subsurface, subsea, topsides, platforms, etc.) involved is also suggested in order to maximize the project objectives. Abundant scientific literature exists on deepwater field development, but limited information appears to be available on the optimal definition of project scope, facilities sizing and design life for a deepwater project that aims to be profitable and sustainable long term. This paper is a contribution to a wider discussion that the industry needs to have on the way deepwater projects are conceived, planned and executed.