3D Modeling of Carbonate Pore and Fracture Permeability for Lower Paleozoic Carbonates, Appalachian Basin

One of the major challenges in carbonate reservoir characterization is to be able to accurately predict the potential for the reservoirs to absorb, permeate, and contain CO₂ for enhanced oil recovery (EOR) and CO₂ sequestration.

Two main geological parameters are required in order to adequately achieve the above goal. The first parameter, permeability, cannot be directly predicted from porosity in carbonate rocks due to the heterogeneous vertical and lateral changes in secondary porosity (mainly represented by vugginess). In this study, rock fabric-based carbonate permeability prediction is proposed through the establishment of porosity-permeability transforms. The results are then integrated with vugginess interpretation from high-resolution seismic data such as compressional wave and shear wave velocity and reflectivity from crosswell seismic profiles.

The second parameter, fracture type and distribution, can be directly measured only from core and image logs at well locations, which is one-dimensional information. Relying on this one-dimensional domain would be of little help in the three-dimensional prediction of fracture type and distribution which is critically important in CO₂ injectivity prediction. To overcome this challenge, this study focuses on fracture interpretation from image logs and cores which is integrated with fracture interpretation from high-resolution crosswell seismic attribute analyses. Results will then be directly incorporated into 3-D geocellular static reservoir model.

Results would allow direct implementation of the three-dimensional distribution of carbonate permeability, fracture type, and distribution in dynamic reservoir modeling in order to predict total CO₂ volumes to be injected, and to accurately predict CO₂ flow in the dynamic reservoir model. This will result in accurate positioning of best locations for CO₂ injection wells, which is a very important decision for both carbon sequestration and EOR (Enhanced Oil Recovery) projects.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California