New Mexico Geological Society Annual Spring Meeting — Abstracts

The Bone Spring Formation of SE New Mexico is comprised of alternating carbonate and siliciclastic units deposited along the shelf margin of the Delaware Basin during Permian time. The Bone Spring can be subdivided, from youngest to oldest, into the 1st carbonate, 1st sand, 2nd carbonate, 2nd sand, 3rd carbonate, and 3rd sand. Previous work has suggested that this pattern of alternating carbonate and siliciclastic deposition is the result of sea level fluctuations. During sea level lowstands, carbonate megabreccias were deposited along the paleoslope and submarine fan systems spread out into the basin depositing the fine-grained sandstones of the first, second, and third sands. The intervening highstands resulted in deposition of the spiculitic limestones, calcareous shales, siltstones, and laminated carbonaceous mudstones of the Bone Spring first, second, and third carbonates. Reservoir rocks within the Bone Spring include carbonate megabreccias and the first, second, and third sands. Traps along the slope are primarily stratigraphic with pelagic sediments acting as cap rocks, and, as a result, drilling targets are regions of high porosity. Given the restricted occurrence of the carbonate megabreccias and the rapid basinward thinning, upslope pinchouts, and general heterogeneity of the submarine fan deposits, a detailed knowledge of the stratigraphic architecture and porosity distribution is necessary to evaluate potential drilling targets within the Bone Spring. The present study addresses this need for a small portion the slope and slope-to-basin transition along the northern margin of the basin. A 3-D seismic survey shot over the area and logs from fifty-one wells were used to determine the stratigraphy of the region. Geostatistical methods were then used to relate rock properties and seismic attributes at the well locations allowing these properties to be predicted in areas without well control.