Browsing by Subject "Facies distribution"
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Item Quantified facies distribution and sequence geometry of the Yates Formation, Slaughter Canyon, New Mexico(2011-08) Harman, Charles Averill; Kerans, C. (Charles), 1954-; Mohrig, David; Frost, EdmundThis study uses a new integrated outcrop data and airborne lidar from Slaughter Canyon, New Mexico, to quantitatively characterize the cycle-scale facies architecture within the G23-G26 high frequency sequences of the Yates Formation. High frequency cycle-scale mapping of these sequences shows sedimentological evidence for accommodation reduction associated with the Permain composite sequence (CS) 13 highstand (G23-G25). Development of the G26 HFS additionally demonstrates the isochronous balance of mixed carbonate-siliciclastic deposition across the Yates-Capitan reef-rimmed shelf during the initial CS-scale transgression following significant exposure and bypass of sand across the shelf. This sequence framework is quantitatively analyzed using progradation to aggradation (P/A) ratios, facies proportions, facies tract dip width, and facies tract bedding angles to evaluate the interplay of eustacy and syndepositional deformation as drivers of stratigraphic architecture. The sequences defined here developed in response to both eustacy and syndepositional deformation, but individual facies distributions and cycle stacking patterns were largely controlled by eustacy; while facies, cycle, and sequence thicknesses as well as facies bedding angles were locally influenced by syndepositional faulting. A reconstruction of each high frequency sequence and stepwise documentation of post-depositional fault displacement and HFS basinward rotation was generated using the lidar data. This analysis shows that the G23-G26 HFS developed basinward-dipping depositional topography from the shelf crest to the shelf margin reef. This geometry was largely unaltered by syndepositional faults during individual HFS deposition, but was rotated basinward shortly thereafter by younger fault movement. The accommodation trends recorded in this largely shelf crest to shelf margin window can be additionally projected into the middle shelf producing zones of the prolific Yates-aged reservoirs on the Northwest Shelf and Central Basin Platform.Item Sequence stratigraphy and depositional systems in the Upper Cretaceous (Cenomanian) Woodbine Group, Anderson and Cherokee Counties, Texas(2016-08) Krueworramunee, Kullamard; Fisher, W. L. (William Lawrence), 1932-; Ambrose, William A.; Mohrig, DavidThe Woodbine Group of the East Texas Basin has attracted considerable interest because of its remaining petroleum resource in the deeper Woodbine pay. Recent estimate of the remaining petroleum resources in the East Texas field is approximately 1.58 billion stock tank barrels (BSTB) (Wang et al., 2008). However, expected ultimate recovery is limited by reservoir compartmentalization controlled by a complex stratigraphic framework. The purpose of this study is to define depositional systems and construct the stratigraphic framework of the Woodbine Group in Anderson and Cherokee Counties to provide the geologic context for characterizing remaining reserves. This study integrates core data and log data from closely spaced wireline logs (~1000 wells), using a chronostratigraphic method, to define sequence stratigraphic units. The stratigraphic framework of the Woodbine succession in the study area is composed of a maximum of 14 cycles in the basin axis, decreasing to a minimum of 3 cycles eastward to the Sabine Uplift and a minimum of 6 cycles westward to the out crop belt. The Woodbine succession is overlain by impermeable deposits of the Eagle Ford Shale and the Austin chalk as hydrocarbon seals. The complexity and heterogeneity of sandstone bodies in the Woodbine Group are largely controlled by depositional origin. Woodbine highstand and lowstand sequences display great variations in the depositional systems. The highstand deposits are composed mostly of fluvial dominated delta deposits that consist of distributary-channel, crevasse-splay, and delta-front deposits. Gamma-ray and spontaneous potential responses for these highstand deposits are upward-coarsening and serrate. In contrast, Woodbine lowstand deposits are mainly composed of coarse-grained sandstones of incised valley fills, reflecting relative base-level fall. These lowstand deposits, truncate older highstand deposits and are inferred from planar-based and blocky serrate log responses. Furthermore, highstand and lowstand deposits are overlain by transgressive deposits. These transgressive deposits are characterized by upward-fining log response, reflecting relative base-level rise. Correlation of sequence stratigraphic surfaces, sandstone-body stacking patterns and reservoir complexity inferred from gross-sandstone maps can lead to new exploration targets in the Woodbine Group in the southern part of the East Texas Basin.