Sullivan, Morgan and Foreman, Lincoln - Exxon Production Research Co., DeVries, Mike - Exxon Exploration Co., Khan, Arfan - Exxon Co. USA
Architectural styles of sandbodies deposited in deepwater settings are highly variable and this variability in sandbody geometry and continuity affects both the exploration and production potential of deep-water sandstones. Outcrops span a critical gap in both scale and resolution between seismic data and well-bore data. Dimensional and architectural data from outcrops can therefore be used to help populate 3-D reservoir models which will be used to predict well performance, connected volumes and recovery efficiencies for newly discovered fields. To assist with reserve assessments and optimization of depletion strategies for the development of the Diana Field, deepwater outcrop analog data were integrated with seismic and well data to produce a detailed 3-D geologic model for more accurate reservoir characterization.
The Diana Field is located in the western Gulf of Mexico in approximately 4700 ft of water and has in excess of 100 MOEB of recoverable hydrocarbons from the Upper Pliocene A-50 reservoir. The situation presented at the Diana Field is a common one: a hydrocarbon reservoir expressed by a single-cycle seismic event and by three appraisal wells spaced thousands of feet apart. There is, however, excellent core coverage which enables close calibration of seismic and well data. Integration of seismic, well and core data suggests a relatively channelized reservoir in an updip position becoming a more sheet-like and layered down dip. This subsurface data did not have the resolution to provide the dimensional and architectural data required to condition the geologic model for flow simulation and well-performance prediction.
To solve these uncertainties, deepwater outcrop analog data from comparable basin floor fan systems were integrated with the seismic and well data from the Diana Field. Bed scale reservoir architectures were quantified with photo-mosaics and by correlation of closely spaced measured sections. Bed continuity, connectivity and vertical and lateral facies variability data were also collected as these factors ultimately control the reservoir behavior. From these measurements, a spectrum of channel dimensions and shapes were compiled to condition the modeled objects. These data were compared to Diana specific seismic and well data and adjusted accordingly. The advantage of the resulting Diana geologic model is that it incorporates geologic interpretation, honors all available data and models the reservoir as discrete objects with specific dimensions, facies juxtaposition and connectivity. This effort provides the framework for optimal placement of wells to maximize the architectural and facies controls on reservoir performance.
AAPG Search and Discovery Article #90933©1998 ABGP/AAPG International Conference and Exhibition, Rio de Janeiro, Brazil