Early life cycle field development planning in a complex Deepwater Gulf of Mexico (GOM) Field is considered. The 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, have been optimized, maximizing net present value while matching field development constraints. Potential well locations and recompletion locations in geologically justified areas have been evaluated. Drilling rig pace, order and associated project and drilling economic constraints have been considered.
BP's TDRM™ Option Evaluation (OE) technology has recently been extended to cover the simultaneous optimization of well completions and recompletions in reservoirs containing multiple stacked pay. This new capability has now been very successfully applied to assisted analysis of more than twenty thousand possible field development scenarios.
Several development plans have been identified which exhibit improved NPV, recovery, sweep efficiency, extension of oil production plateau and an expanded drilling holiday, in comparison with a manually designed development plan reference case. Balanced production from different reservoir zones has been achieved. Finally, TDRM™ OE results were demonstrated to be robust across multiple structural and faulting interpretations of the subsurface, generated by independently determined seismic interpretations of the subsurface strata.
Computations were predominately performed in a black oil simulator formulation, with high potential cases being repeated using a 16 component compositional formulation in order to more accurately represent the rich condensate zones. The Nexus® reservoir simulator, run under the control of TDRM™ OE was successfully used to carry out the actual computations.
Assisted history matching technologies have been under development and deployment within BP for over a decade now (Williams et al., 2004). Utilization of these technologies has proven extremely useful in 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 particular field (Litvak, et al., 2007).
These technologies couple with existing full physics reservoir simulators such as Nexus®, VIP® and ECLIPSE®. They rely upon search and optimization algorithms such as genetic algorithms, Monte-Carlo and / or other optimization / search routines. Within BP workflows using these technologies are becoming common place for establishing the development plan for an oil, gas or condensate field.