This paper investigates how decisions made through reservoir evaluation and drilling-and-completion planning affect the design of subsea production systems and, in turn, the design of production hosts. Practical alternatives are explored by challenging the current approach to project framing and definition. Rethinking the requirements of deepwater-field development will help define the proper size of the subsea and surface facilities, the optimal design life, and the possible need for staged developments.
During the past 2 years, the offshore industry has looked with increasing interest, and undeniable concern, to practical and effective ways to reduce the capital expenditure (Capex) of deepwater projects.
Looking at the three main components of a deepwater-field production infrastructure—host, subsea production system including export, and subsea wells—the host offers the greatest opportunity for Capex reduction. Cost reduction is achievable by optimizing the subsea production system and by adopting new technologies and practices for the construction of subsea wells, but a more relevant cost reduction is possible in principle by properly sizing the host. This, in turn, requires rethinking the way deepwater projects are sanctioned and contracts between local governments and operators are negotiated.
The fact that over capacity exists in offshore hosts is well-documented. Less evident, but still convincing, is the fact that several subsea tiebacks, successfully conducted over the past decades across the world, were possible only because a host already existed nearby that had available process or storage capacity.
Sometimes, overdesigning a host may not be avoidable because of the limited time the operator has to develop and produce the offshore fields. If contracts were structured in a different way and the operators had the chance to operate the offshore field for a longer period, it might have been possible to use smaller hosts and subsea production systems, thus reducing both Capex and operational expenditure (Opex).
Approach Redefines Ideal Project Scope and Facilities Size for Field Development
01 October 2017