Part 4 - Berg - Hughes Center
Part 4 - Berg - Hughes Center
Part 4 - Berg - Hughes Center
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10%. Calcite-lined vugs and intergranular openings are the main porosity types.<br />
Permeability likewise is generally low, commonly being less than 0.1 md but reaching as<br />
high as 100 md in small intervals. The hydrocarbons produced are light oils and<br />
condensates, as well as gas in porous limestone intervals. Because of the combination<br />
stratigraphic-structural anomalies present in the area, the James was considered an<br />
excellent exploration target (Hermann, 1976).<br />
Rodessa Formation<br />
Producing Parishes<br />
Caddeo, Bossier, Webster, Claiborne,<br />
Lincoln, Bienvilole, De Soto, Red River<br />
The term Rodessa Formation includes the strata above the James Limestone and<br />
below the base of the Ferry Lake Anhydrite (Roberts and Lock, 1988). The type well for<br />
the formation is located in Rodessa Field, Caddo Parish, Louisiana (Forgotson, 1957). In<br />
the type well, the Rodessa interval is at depths of 5,320 to 5,805 ft. In this part of<br />
Louisiana, the Rodessa Formation consists of oolitic and crystalline limestones, lenticular<br />
fine-grained sandy limestone, anhydrite, coquinoid limestones and gray shales.<br />
Southward from the type area in northwest Louisiana, the limestones of the Rodessa have<br />
reduced porosity and grade into dense, crystalline limestones. The Rodessa siliciclastics<br />
were derived from the craton to the north. Ostracode assemblages in the Rodessa are<br />
typical of open-to-restricted shelf environmental conditions. Yurewicz et al. (1993)<br />
described the Rodessa in east Texas as typically skeletal–peloid-oncoid packstone that<br />
grades downdip into skeletal grainstone and packstone shoals and rudist and coral-red<br />
algae at the platform margin.<br />
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