Agbami Field Development Concept Selection: Evaluating Facility and Field Development Alternatives in an Environment of Significant Subsurface Uncertainty

摘要

Planning the development of the Agbami field offshore Nigeria,rnas with other deepwater projects, required that criticalrnbusiness decisions be made in the absence of extensive subsurfacerndata. Along with other fundamental project componentsrnthat have a range of possible outcomes-for example,rnfinalized commercial terms, wells and facilities costs, andrnexecution schedule duration-the project team had to effectivelyrnunderstand, communicate, and incorporate all the keyrnsubsurface uncertainties in the process of achieving certainrnfield development decisions.rnChevronTexaco uses its gated five-phase ChevronTexacornProject Development and Execution Process (CPDEP) to maturernand execute all major projects. In “CPDEP-speak,” PhasernTwo involves the generation and selection of alternatives.rnPhase Three is where a “Preferred Alternative” is refined inrnpreparation for project execution in Phase Four. Additionalrnexplanation of CPDEP follows in a separate section.rnPrior to moving the project into Phase Three, two criticalrnfield development options required resolution: 1) facility processingrnand injection capacities (oil, gas, water); and 2) a dryrntree unit (DTU) versus all-subsea development decision. Itrnwas required that these development plan options be evaluatedrnover the range of possible subsurface and cost regime outcomesrnin order to select the optimum development scheme.rnProbabilistic estimates for reserves, well count, facilityrncosts, well costs, and schedule were developed. Uncertaintiesrnsuch as a potential reserve differences between dry and wetrntree development and management of multiple contracts werernincluded in the options analysis. Other operators’ decisions forrnsimilar deepwater developments were benchmarked for bestrnpractices and lessons learned.rnVarious project variables were ranked in terms of projectrnimpact in order to determine which ones drove each decisionrnand therefore which ones needed to be most fully evaluated inrnterms of understanding the range of possible outcomes.