Depositional and stratigraphic controls on reservoir distribution within the Rodessa Formation in northwest Louisiana.

Abstract

The Lower Cretaceous Rodessa Formation of the Trinity Group was deposited on a carbonate platform within the North Louisiana Salt Basin in northwest Louisiana. Core analysis of a productive flow unit in the upper Rodessa, which is labeled as the DeBroeck interval indicated a maximum of 21.3% porosity, and 49.6 mD permeability. Fourteen lithofacies were described for 2 cores from the DeBroeck 33 No. 1 and McFerren 36 No. 2 wells. The key reservoir lithofacies in the DeBroeck interval include burrowed bioclastic packstone, burrowed peloidal packstone, burrowed peloidal grainstone, rudistid rudstone, and rudistid framestone. Lithofacies indicate an open marine environment of varying depth. The spatial distribution of the DeBroeck interval was mapped over the study area in northwest Louisiana, indicating carbonate bank trends. Supplemental well log analysis of porosity and an estimate of permeability reveal that the best prospects for hydrocarbon production lie within the carbonate banks.