Routine lab characterization of conventional cores is often limited to geology, petrophysics, and mineralogy. With gas shale plays, however, geochemistry and rock-mechanic are key parameters to characterize as well. In this paper, we present several innovative techniques which allow coping with challenges associated with lab characterization on gas shale core samples.
Such alternative techniques need addressing the following issues:
Complex lab measurements, potentially to the threshold of what routine lab devices can characterize.
Potentially high vertical variability of mineralogy and organic content.
Two innovative and worldwide unique measurement devices have then been developed in-house:
A transient permeameter, the Step-Decay device, capable of measuring permeability down to the nanoDarcy, at different levels of confining stress and connate water content.
A high-resolution geochemical core logging tool, the LIPS device (Laser Induced Pyrolysis System), designed to measure the organic matter content on a continuous centimeter scale basis.
So as to cope with the variability issue, a comprehensive set of high resolution core logs has been systematically run: CT-scan and spectral GR logs for petrophysics, scratch-test log for rock-mechanic, and LIPS log for organic matter quantification; we combine all these techniques together for a better core characterization.
We present the analysis workflow applied to a gas shale case-study, insisting on the challenges we faced and the way we coped with them. Benchmarking with alternative techniques and lab results is presented as well.