ABSTRACT

The sediments of the Upper Wilcox at the Lake Creek Field, located within the Houston Embayment, developed as a part of the Columbus delta system and later the Harris delta/strandplain systems, as mapped by Miller (1989). The Upper Wilcox in the vicinity of Lake Creek has been divided into 12 intervals (parasequences). Six of these intervals, labeled from the base as #5, #4, #3, #2, #1, and La Gloria, are reservoir intervals and have been divided into 21 mappable depositional units for detailed facies analysis. A depositional unit may represent either a local progradational, aggradational, or retrogradational stage of parasequence development. Detailed maps of framework sand distribution and log facies, integrated with descriptions of whole-core, provide the basis for facies characterization of the reservoirs at Lake Creek. The interpreted facies distribution for the reservoir intervals of the Upper Wilcox at Lake Creek indicates a complex interplay of fluvial and marine processes. This paper illustrates the interpreted depositional facies of selected depositional units from the #5, #3, and #1 intervals. The diversity of facies within the intervals of the Upper Wilcox at Lake Creek, and thus the degree of heterogeneity, can be correlated with the position of the event within the estimated hierarchy of the depositional cycles.