Geomechanics of coal-gas interactions: the role of coal permeability evolution

Zhongwei Chen

    Research output: ThesisDoctoral Thesis

    524 Downloads (Pure)

    Abstract

    [Truncated abstract] Complex interactions between stress and sorptive chemistry exert strong influence on coal geomechanics. These include influences on gas sorption and flow, coal deformation, porosity change and permeability modification. In this study, this chain of reactions is labelled as "coupled processes" implying that one physical process affects the initiation and progress of another. The evolution of coal permeability is probably the most important cross coupling to rigorously formulate the Geomechanics of coal-gas interactions. There are an extensive suite of coal permeability models available in the literature – with many of these models implemented into computer simulators to quantify coal-gas interactions. The comparison of laboratory and field observations against the spectrum of models indicate that current models have so far failed to explain the results from stress-controlled shrinkage/swelling laboratorial tests and have only achieved some limited success in explaining and matching in situ data. Almost all the permeability models are derived for the coal as a porous medium, but used to explain the compound behaviours of coal matrix and fracture. These review conclusions suggest that the impact of coal matrix-fracture compartment interactions on the evolution of coal permeability has not yet been understood well and further improvements are necessary. This knowledge gap defines the goal of this study. The issue as defined above has been addressed through an integrated approach of experimental study, permeability model development, its implementation into a FE simulator, and applications to field operations...
    Original languageEnglish
    QualificationDoctor of Philosophy
    Publication statusUnpublished - 2012

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