Integrated Characterization of Middle East Outcrops: From Rocks to Fluid Flow Simulation

L. J. (Jim) Weber¹, Lee Vaughan¹, and Sameer Khan^2
1ExxonMobil Exploration Company, Houston, TX
²ZADCO, Abu Dhabi, United Arab Emirates

Development plans for hydrocarbon reservoirs are designed to maximize recovery in a cost-effective manner. As most development plans today are based on sophisticated fluid-flow simulation models, any data that increases model accuracy can directly impact business decisions.

Outcrops are particularly useful when combined with subsurface data sets and are used in this study as input to geologic models. Outcrops help to integrate the continuous, large-scale coverage of seismic with the fine-scale resolution of core. Modeling parameters such as lateral and vertical continuity (variogram range), object dimensions (aspect ratios), detailed reservoir architecture (layering), facies relationships and the nature and extent of diagenetic features can be observed and measured.

To better understand a major reservoir in the Middle East, a fluid-flow simulation element model was created from time-equivalent, analogous outcrops in Ras Al-Khaimah. Twenty-seven horizons (representing parasequence caps, flooding surfaces, and sequence boundaries) and eleven lithofacies were described in four measured sections. Porosity log curves and core data from equivalent facies in a subsurface oil field were used in the modeling to account for differences in burial history between the outcrops and subsurface reservoirs.

Data analysis indicated that flow behavior in the modeled section could be described by four composite reservoir facies (3 permeable and 1 “dense”). These facies were modeled and up-scaled and underwent flow simulation. Multiple scenarios were investigated, including various injection patterns, scale-up methods and locations of thin, high-permeability streaks. Results mimicked known behavior in analogous producing fields and the process of going from rock data to simulation provided a useful training tool for reservoir characterization methods and techniques.

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas