Correlation of the lithostratigraphic facies relationships and depositional environments of the uppermost Silurian through Lower Devonian strata across the central Darling Basin, western New South Wales, SE Australia

Abstract

This paper is focused on the detailed lithostratigraphic facies characterisation of the paleo-environments of the uppermost Silurian through Lower Devonian Winduck Interval strata from the Bancannia South 1, Pondie Range 1 and Booligal Creek 1 and 2 wells, across the central Darling Basin of western New South Wales. Based on data from both wireline logs and drill cores and cuttings, an interpretation of paleo-environments and evolution of the depositional facies is presented. Our approach involves two key interpretations. The first outcome was the delineation of the Winduck Interval section (maximum observed thickness of approximately 1475 m) and formal subdivision into lower and upper Winduck Intervals, based on well data from the central Bancannia Trough, southern Pondie Range Sub-basin and northwestern flank of the Blantyre Sub-basin. The second outcome is based on the internal lithostratigraphy of the Winduck Interval represented by 11 sedimentary lithofacies organised into three lithofacies associations (LFAs). LFA-X1 is interpreted as distributary-channel sandstone complex deposits, LFA-X2 is interpreted as distributary mouth bar with small-scale braided delta plain complex deposits and LFA-X3 is interpreted as tidal channel sands with proximal delta front complex deposits. Subsurface lithostratigraphic facies analysis relationships and depositional environments of the Winduck Interval section have implications for evaluating the hydrocarbon potential and may assist future exploration efforts in the central Darling Basin, especially the Bancannia Trough and Pondie Range Sub-basin. KEY POINTS A detailed lithostratigraphic facies characterisation of the paleo-environments of the uppermost Silurian–Lower Devonian Winduck Interval strata in the central Darling Basin is presented. Evaluation and interpretation of the Winduck Interval section in study area was subdivided into two informal stratigraphic units, a lower Winduck Interval and an upper Winduck Interval. Eleven distinct sedimentary lithofacies codes (LFs), which have been recognised in the internal lithostratigraphy of the Winduck Interval from the Bancannia South 1, Pondie Range 1 and Booligal Creek 1 and 2 wells, have been grouped into three lithofacies associations (LFAs). Lithostratigraphic facies analysis relationships and depositional environments of the Winduck Interval section has implications for evaluating the hydrocarbon potential and may assist future exploration in the Bancannia Trough and Pondie Range Sub-basin.