Characterizing Pore Network Architecture in Gas Shales: Relating Core-Scale Measurements of Gas Transport to Pore-Scale Structure

Michael Cronin
The University of Texas at Austin, John A. and Katherine G. Jackson School of Geosciences Austin, Texas, United States of America
[email protected]

The purpose of this project is to define the fundamental pore network architecture in gas shale matrix such that quantitative predictions for gas transport can be made over a variety of length, time, and pressure scales. This project seeks to integrate experimental measurements of gas transport in shale with matrix characterization data derived from scanning electron/atomic force microscopy (SEM/AFM) and mercury intrusion capillary pressure (MICP) curves to develop models of shale pore network architecture that are capable of being verified at the core-scale.

A key motivation for analyzing transport behavior and matrix architecture at the core to sub-core scale in shales is to help inform the considerable debate as to whether intact core or crushed-rock (GRI method) permeability experiments are more representative of in-situ gas permeability.

I am conducting transient pulse decay (TPD) and steady-state (SS) permeability tests on re-cored samples of the Barnett shale using a hydrostatic pressure cell to examine the effect of effective stress and gas slippage (Klinkenberg effect) on the permeability of Barnett shale matrix to argon gas. In addition to core-scale flow through permeability experimental data, crushed-rock permeability, gas adsorption, and mercury intrusion capillary pressure (MICP) data have been obtained to provide a basis for developing an initial pore network model for the Barnett samples tested. It is hoped that this study will identify the simplest representation of shale pore network construction (connectivity and distribution of pore sizes) that will remain useful in predictions of gas transport.

AAPG Search and Discovery Article #90157©2012 AAPG Foundation 2012 Grants-in-Aid Projects