Quantification of the Vertical and Lateral Heterogeneity of Distal Submarine-Lobe Deposits, Wolfcamp Formation, Delaware Basin, Texas: Implications for Subsurface Lateral Prediction

Submarine-lobe deposits host important archives of paleo-environmental change and are major targets for exploring and producing hydrocarbons. Traditional models of submarine-lobe architecture typically exhibit a systematic decrease in bed thickness, grain size, sand content, and amalgamation from proximal to distal and from axis to fringe. However, recent studies in these submarine environments, driven by petroleum explorations and carbon sequestration endeavors, have revealed complex lateral heterogeneity, particularly at the bed scale. This study focuses on two cored wells from the Gas Technology Institute Hydraulic Fracturing Test Site 2 of the Wolfcamp A Formation, Delaware Basin. The datasets include one vertical well and one slant well, accompanied with well log data, CT scans, core photos, and XRF data. This study is specifically focused on linking vertical and slant core datasets to provide constraints on vertical and lateral heterogeneity over a relatively short distance (380.6 to 1007.2 ft) and event-bed architecture in the context of mixed carbonate–siliciclastic submarine lobe deposits.

Notably, the Hybrid Event Bed (HEB) sequences present calcium-rich layers at the base of beds that progressively transition upwards into silica- and clay-rich intervals. In addition, the lateral heterogeneity analysis unveiled considerable differences in event-bed layer thickness and composition over relatively short distances. In general, the slant well is richer in Ca when compared to the vertical well.

These findings aid in the prediction of subsurface heterogeneity in conventional and unconventional hydrocarbon reservoir systems through reservoir model parameterization as well as characterization of lateral heterogeneity important for horizontal-well geosteering and completion strategies.