--> Abstract: A Digital Outcrop Analog for Upper Paleozoic Carbonate Slope Reservoirs, by Jerome A. Bellian, Ted Playton, Jeroen Kenter, Paul M. Harris, and James Ellis; #90124 (2011)

Datapages, Inc.Print this page

AAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA

A Digital Outcrop Analog for Upper Paleozoic Carbonate Slope Reservoirs

Jerome A. Bellian1; Ted Playton1; Jeroen Kenter1; Paul M. Harris1; James Ellis2

(1) Chevron ETC, San Ramon, CA.

(2) Ellis Geospatial, Walnut Creek, CA.

Production from Upper Paleozoic isolated carbonate platforms is prolific, including several super-giant fields in the Precaspian Basin that have produced many hundreds of millions of barrels. As these reservoirs mature, well locations commonly shift from the relatively homogeneous platform facies into the slope portions of the buildups. The heterogeneity of slopes, where deposits are variable mixtures of margin-derived breccias and platform-derived grainy to muddy sediment transported through an irregular margin, leads to a spectrum of deposit types, complex pore structures, and variable reservoir quality.

To better constrain slope styles and shelf-to-basin depositional models, a detailed examination of superbly-exposed Permian margin, slope, and basinal outcrops (Capitan and Bell Canyon Formations) was conducted along a portion of the southern Guadalupe Mountains using a combination of airborne lidar, spectral analysis of ASTER data, and conventional field work. This locality offers world-class exposures of Upper Permian mixed carbonate and siliciclastic shelf to basin deposits that are well-preserved and with minimal structural deformation. Slope and basin deposits equivalent to the Seven Rivers and Yates Formations were the focus of this study.

The preliminary results from this work show vertical stacking patterns of siliciclastic siltstone and very-fine-grained sandstones that are overlain by platform-derived packstone-to-grainstones followed by platform- and margin-derived breccia clasts. The current model suggests that incision and clastic sediment are related to shelf bypass during lowstand whereas the carbonate platform grains and margin debris were transported during sea-level transgression to highstand, respectively. Identification of these features on airborne lidar data made it possible to define slope-channel paleoorientation and geometry. Channel orientation and geometry combined with relative proportions of clastic and carbonate infill were used to define position along depositional dip as a proxy for along-strike variability of the platform margin.