Geology and oil and gas assessment of the Mancos-Menefee Composite Total Petroleum System: Chapter 4 in &lt;i&gt;Total petroleum systems and geologic assessment of undiscovered oil and gas resources in the San Juan Basin Province, exclusive of Paleozoic rocks, New Mexico and Colorado&lt;/i&gt;

Ridgley, Jennie L.; Condon, Steven M.; Hatch, J.R.

doi:10.3133/ds69f4

Cited by 5 publications

(1 citation statement)

References 7 publications

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“…The Mancos Shale Formation, deposited along the steep margin of the Western Interior Seaway during most of the Cretaceous [ Kauffman et al ., ], has several members such as dark gray (and black) calcareous and noncalcareous shales and interbedded sandstones. It has various thicknesses in the San Juan Basin [ Landis et al ., ; Ridgley et al ., ] and the Uinta and Piceance Basins [ Hettinger and Kirschbaum , ]. The Cretaceous Mancos Shale consists of a variety of lithofacies (i.e., rocks deposited in a distinct depositional environment) and relatively thin sandier layers contained in the sealing source muds, which was considered to be a regional seal [ Shipton et al ., ].…”

Section: Methodsmentioning

confidence: 99%

Effects of spatial heterogeneity and material anisotropy on the fracture pattern and macroscopic effective toughness of Mancos Shale in Brazilian tests

Sun

Ingraham

et al. 2017

JGR Solid Earth

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For assessing energy‐related activities in the subsurface, it is important to investigate the impact of the spatial variability and anisotropy on the geomechanical behavior of shale. The Brazilian test, an indirect tensile‐splitting method, is performed in this work, and the evolution of strain field is obtained using digital image correlation. Experimental results show the significant impact of local heterogeneity and lamination on the crack pattern characteristics. For numerical simulations, a phase field method is used to simulate the brittle fracture behavior under various Brazilian test conditions. In this study, shale is assumed to consist of two constituents including the stiff and soft layers to which the same toughness but different elastic moduli are assigned. Microstructural heterogeneity is simplified to represent mesoscale (e.g., millimeter scale) features such as layer orientation, thickness, volume fraction, and defects. The effect of these structural attributes on the onset, propagation, and coalescence of cracks is explored. The simulation results show that spatial heterogeneity and material anisotropy highly affect crack patterns and effective fracture toughness, and the elastic contrast of two constituents significantly alters the effective toughness. However, the complex crack patterns observed in the experiments cannot completely be accounted for by either an isotropic or transversely isotropic effective medium approach. This implies that cracks developed in the layered system may coalesce in complicated ways depending on the local heterogeneity, and the interaction mechanisms between the cracks using two‐constituent systems may explain the wide range of effective toughness of shale reported in the literature.

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Section: Methodsmentioning

confidence: 99%