Observed multi-scale porosity and permeability at the cm-scale in Barnett Shale.
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Developed a model to interpret permeability of high and low permeability layers.
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Integrated pulse-decay testing with computed tomography and detailed SEM imaging.
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Microstratigraphy of mudstones has a fundamental control on flow behavior.
Abstract
We observed multi-scale porosity and permeability at the cm-scale in a Barnett Shale core through a pulse-decay permeability test. The core is composed of alternating layers of silty-claystone and claystone. We interpret the silty-claystone has a permeability of 3.41×10−20 m2 (34.6 nD) and a porosity of 5.6% and that the claystone has a permeability of 1.80×10−23 m2 (0.0182 nD) and a porosity of 4.8%. The horizontal effective permeability is 2.05×10−20 m2 (20.8 nD) and we estimate the vertical effective permeability to be 4.58×10−23 m2 (0.0452 nD). The effective permeability anisotropy ratio is approximately 450. These results suggest that relatively high-permeability carrier beds drain organic rich lower permeability beds. The microstratigraphy of mudstones has a fundamental control on flow, and may provide an explanation for recent studies that have suggested either pervasive natural fracturing or extraordinary levels of induced fracturing are necessary to explain shale production behavior.
