Early-Life Field-Development Optimization of a Complex Deepwater Gulf of Mexico Field

Abstract

This article, written by Editorial Manager Adam Wilson, contains highlights of paper OTC 22252, ’Early-Life-Cycle Field-Development Optimization of a Complex Deepwater Gulf of Mexico Field,’ by Patrick F. Angert, SPE, BP Exploration; Obiajulu J. Isebor, SPE, Stanford University; and Michael L. Litvak, SPE, BP Exploration, prepared for the 2011 Offshore Technology Conference Brasil, Rio de Janeiro, 4-6 October. The paper has not been peer reviewed. A complex deepwater Gulf of Mexico field contains several stacked hydrocarbon-bearing intervals charged with volatile oil or rich gas condensate. Well locations, drilling schedule, and reservoir units into which wells will be initially completed and then later recompleted were optimized, maximizing net present value (NPV) while matching field-development constraints. Potential well locations and recompletion locations in geologically justified areas were evaluated. Drilling-rig pace and order and associated project and drilling economic constraints have been considered. BP’s Top Down Reservoir Modeling (TDRM) Option Evaluation (OE) technology has been extended to cover the simultaneous optimization of well completions and recompletions in reservoirs containing multiple stacked pay. Introduction Assisted-history-matching technologies have proved extremely useful for identifying multiple geologically plausible matches of historical production and surveillance data within existing fields. Assisted field-development optimization, although slightly newer, is nevertheless proving extremely useful in the identification, categorization, understanding, and ranking in economic and recovery terms of the multitude of possible development scenarios that could be implemented to produce oil, gas, or condensate from a field. These technologies couple with existing full-physics reservoir simulators and rely on search-and-optimization algorithms such as genetic algorithms, Monte Carlo, or other optimization/search routines. Typically, tens of thousands of possible development scenarios are generated in search of a much smaller set that meets all of the initial criteria specified while achieving higher overall project NPV and recovery. High potential cases are then investigated further, and, ultimately, a final development scenario is selected and refined further as a project progresses toward a final investment decision and commitment of project development capital. Field Background For the field under investigation, rich-gas-condensate and volatile-oil accumulations sit in a water depth greater than 6,000 ft. The upper hydrocarbon-bearing intervals occur below approximately 24,000-ft true vertical depth subsea (TVDSS) and extend to greater than approximately 29,000-ft TVDSS. The highest initial pressure of a hydrocarbon-bearing interval is approximately 20,000 psia.