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XRF and LiDAR Survey of Bone Canyon, West Texas: A High-Resolution Sequence Stratigrphaic Framework Providing Insight into Updip Deepwater Lithofacies

The Leonardian Bone Spring formation is one of the dominant oil and gas producing formations in the Northern Delaware Basin today. It is Leonardian in age and lies just below the Guadalupian Cutoff formation. The majority of the production came from diagenetic, secondary porosity developed in carbonate debris flows and slump deposits derived from the shelf margin. New developments in drilling, production, and development technologies have allowed for a shift in primary target focus down dip into the basin. The Bone Spring Formation provides at present one of the most active unconventional plays in the Permian Basin today. Therefore, optimizing the sweet spots where extractable oil occurs by preservation in anoxic environments and where it is most brittle is critical to its economic exploitation. Understanding the stratigraphy and lithologic variation of the Bone Springs and how it relates to changes in sea level are best viewed at the updip portion of the slope facies.

With respect to the reciprocal sedimentation paradigm, there appears to be an additional complication if the changes in carbonate and clastic are solely related to changes in sea level. For example, the uppermost carbonate within the First Carbonate clearly shows that increases in terrigenous sediments are associated with increases in chert and dolomite. While differences in the stratigraphic nomenclature exist between the outcrop and the subsurface, this investigation clearly reveals more details on the lithofacies fabric and texture than can be seen by well control alone and suggests that some of the differences in nomenclature may be due to sample bias or to real differences in depositional system geometries. However, the information revealed by this high-resolution stratigraphy may be potentially confirmed with correlation to the subsurface.

It is for this reason that the preliminary data presented were acquired in the classic exposure which crops out in Bone Canyon of the Guadalupe Mountains. The canyon contains the stratigraphically highest units of the Bone Springs formation including the Avalon Shale representing the updip portion of these basin fed systems. This will give insight into the stratigraphic placement of the Avalon. These formations were imaged using LiDAR where auxillary data was collected. Reflectance images can be constrained by XRF confirmed lithologic differences. Pseudo Gamma Ray logs for each transect were created by taking the XRF values of Potassium (K), Thorium (Th), and Uranium (Ur) and using the equation:

ϒ API = 4 Th + 8 U + 16 K

This study will give insight into the Bone Spring Formation, what makes it such a prolific oil and gas formation, and other similar systems worldwide.