An Integrated Approach to Reservoir Characterization and Geo-Cellular Modeling in an Unconventional Reservoir: The Woodford Play

Dicman Alfred, Benjamin Ramirez, Jesus Rodriguez, and Kimbery Hlava

A fine scale, geologic reservoir model is key to improve predictability of high performance zones in the Woodford play, which is characterized by fractured, heterogeneous mudrock. A model is also paramount for well placement, drilling hazard predictions, and hydraulic stimulation evaluation. The nature of the fracture contribution has been included through a workflow that generates spatially distributed fracture characteristics based on well performance and static attributes derived from well observations and seismic information. The integrated workflow includes a stratigraphic framework built within the Woodford Formation. The Woodford is divided into five groups internally using facies changes, biostratigraphic information, and log signatures. From core descriptions and x-ray diffraction data, it is observed that total organic carbon and clay are the main drivers for Woodford depositional facies and intrinsic reservoir properties. Correlations that relate total organic carbon and clay volumes to seismic information, such as acoustic impedance and bulk density, enable the construction of petro-elastic models. Using petroelastic models, a petrophysical seismic inversion is used to derive density, total organic carbon, and clay volumes. Structural seismic attributes such as dip, curvature, and coherence are also incorporated into the model. Finally, correlations obtained from multivariate statistics of well performance data and static model properties are applied to create spatial distributions of natural fractures drivers including: fracture permeability and shape factor distributions across the field. The application of this workflow is demonstrated through a local sector model history match with excellent agreement to production history. The predictive model is blind tested with new wells and compared with microseismic yielding satisfactory results.

AAPG Search and Discovery Article #90176©AAPG Mid-Continent Meeting, Wichita, Kansas, October 12-15, 2013