Master of Science (MS)
Geology and Geophysics
The Haynesville Shale in East Texas and Northwest Louisiana is one of the most studied and explored shale-gas plays in the United States. With new horizontal drilling and completion strategies, energy companies can produce hydrocarbons directly from the source rock making the Haynesville Shale an attractive resource. A key component of enhanced hydrocarbon production is the presence of natural fractures. They may serve as permeable pathways for hydrocarbon flow, especially in tight shales such as in the Haynesville Shale, where the matrix permeability is very low. In the case of the Haynesville Shale, little is known about the occurrence of natural fractures and their effect on hydrocarbon production (Hammes et al., 2011). In this study, natural fractures in a 160 feet continuous, conventional core of Haynesville Shale are imaged and characterized using visual inspection, x-ray computed tomography scans (CT scans), x-ray diffraction (XRD), scanning electron microscopy (SEM) and thin section analysis on selected core plugs. The purpose of this study is to characterize natural fractures in the Haynesville Shale by identifying fracture orientation, fracture fill and how these features correlate with mineralogy. A popular method for determining permeability and porosity in rocks is to use high-resolution x-ray computed tomography (CT). Computed tomography provides nondestructive three-dimensional visualization and characterization, creating images that map the variation of x-ray attenuation within objects, which relates closely to density (Ketcham and Carlson, 2001). Software used in this study to view the CT scans is called Avizo® Fire. The CT scans provide fracture density, fracture orientation and density of the matrix. Scanning electron microscopy, x-ray diffraction and petrographic microscopy are then used to provide petrographical information on the Haynesville Shale core. The petrographic analysis can be used to make a potential correlation between mineralogy (i.e. clay, calcite and TOC) and fracture density. Both vertical and horizontal fractures are identified in the core along with fossils, burrows and sediment gravity flows. Core and computed tomography scans reveal the presence of seven natural near vertical fractures filled with calcite cement. Porosity is present between the cement and wall rock along fractures and ammonites. Quartz and calcite are the dominant minerals present in the core and contribute to the brittle nature of the rock.
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Morgan, Frank Leslie, "Natural Fracture Characterization in the Haynesville Shale, East Texas: A Core Study" (2013). LSU Master's Theses. 1942.