Abstract

The facies architecture of fluvial-dominated delta plain systems were reconstructed for several Middle Pennsylvanian sandstones. The study area incorporates approximate 640 acres centered on the Amoco experimental drilling site near Port of Catoosa. Data included conventional logs from 11 wells, and core plus microresistivity images from a single well.

Architecture elements recognized are divided in four hierarchical levels, in order of decreasing rock volume: multistacked discrete genetic interval; individual discrete genetic interval (DGI); facies; and stratification pattern of a single facies. Conventional logs are used to correlate and map multistacked DGI, individual DGI, and facies. Core and microresistivity images are used to resolve facies and stratification patterns in the vicinity of the experimental well. Using azimuthal relationships among architecture elements, the location of the experimental well within the depositional systems are determined.

Examples of architectural reconstruction include the following. The Bartlesville sandstone consists of splay facies in the upper part and channel-fill facies on the lower part as two individual discrete genetic intervals. The channel-fill facies shows a fining-upward profile with cross strata at the bottom to parallel strata and ripple laminae at the top. The splay facies is made up of small-scale cross strata, climbing ripple laminae, and parallel strata. Lower Skinner sandstone is 50 feet thick and in conventional well logs forms a single bell-shaped log profile. However, the microresistivity log clearly shows that it is composed of two DGI's, each represented by channel-fill facies.