Abstract

Thin-sectioned well cuttings provide a low-cost yet widely available and underused source of subsurface data that can be used to generate high-resolution sequence stratigraphic frameworks in variably consolidated carbonate-prone units in basins that lack cores or high-quality suites of wire-line logs. Because of the shallow (<1 km) depths of many Cenozoic basins, there is limited downhole mixing of cuttings. Although these carbonate-prone basins are widespread globally, they generally have not been subject to analyses of high-resolution sequence stratigraphy because of the sparsity of outcrop and core data. We used plastic-impregnated thin sections of unwashed well cuttings from a Paleogene carbonate-prone succession from the coastal plain of North Carolina to define the stacking patterns of the facies in the subsurface. This data set, along with biostratigraphic, wire-line log, and seismic data, was used to generate the framework of regional, lithology-based sequence stratigraphy. Systems tracts were determined by correlating vertical changes in the percentages of rock types in the well cuttings. Sequence boundaries were picked beneath units having the maximum abundance of quartz sandstone cuttings; maximum flooding surfaces were picked beneath the units having the most abundant cuttings of deepest marine facies. Thus, despite some downhole mixing, thin-sectioned well cuttings can be used to generate lithology-based sequence stratigraphic frameworks for shallow, carbonate-prone sedimentary basins, which previously were inaccessible except by expensive deep-coring programs.

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