Abstract

The Lower Permian outcrops of Victorio Canyon, in the Sierra Diablo Mountains in west Texas, show undisturbed stratigraphy of carbonate toe-of-slope and basinal deposits. These rocks consist of a vertical stack of carbonate debris-flow deposits and hyperconcentrated density-flow deposits, thick skeletal-ooid grainstone deposited as basin-floor fans, various reworked muddy carbonate deposits, and fine siliciclastic siltstones. This succession was deposited within five sequences that include the upper Hueco Formation (late Wolfcampian) through the Bone Spring Formation (middle Leonardian). Using a ground-based light detecting and ranging-generated high-resolution digital outcrop model (DOM) aged as a template, we mapped and digitized the stratigraphy of the toe-of-slope and basinal deposits on the 5-cm (2-in.) precision DOM. On the basis of the digitized stratigraphic contacts, several regional surfaces were constructed, and a 3-D geocellular model was built. Facies information within this model is extrapolated from measured section data using both a kriging algorithm and stochastic simulations. Using impedance values extracted from a subsurface analog, a 3-D impedance model was created for both the kriged and the stochastic models. Both models incorporate fine-scale stratigraphic architecture. In addition, the stochastic impedance model incorporates spatially correlated noise, resulting in more realistic synthetic seismograms. Three-dimensional synthetic seismograms were calculated at 20, 40, and 80 Hz. The reservoir-prone facies is skeletal-ooid grainstone deposited as a 1.5-km × 750-m (0.93-mi × 2460-ft) basin-floor fan up to 15 m (49 ft) thick. This basin-floor fan is subtly imaged in vertical seismic section at a frequency below 80 Hz. It is, however, better recognized on time slices with peak frequency as low as 20 Hz and even better delineated on horizon slices that parallel the stratigraphy.

You do not currently have access to this article.