Abstract Shale reservoirs host ubiquitous multi-scale natural fractures created by factors such as pore pressure build-up after petroleum generation and palaeo crustal stress changes during tectonic episodes. Natural fractures are among postulated drivers of stimulated shale well productivity and related variability. Quantifying the aforementioned role and optimizing recovery call for litho-structural assessments. In this interdisciplinary study, natural fracture density (fractures per unit length) for North and South American shales (Marcellus, Eagle Ford, Haynesville, Barnett, Fayetteville and Vaca Muerta) was estimated from published observations of outcrops, cores and borehole images. Associated production for the latest horizontal wells, drilled in the most productive locations (sweet spots), was normalized by lateral length and reservoir thickness. It was found to correlate positively with the density of small-scale natural fractures. Durations of transient linear flow, diagnosed from production data, were play-specific, negatively correlated with small-scale natural fracture density and led to realization of picodarcy matrix permeability. Conversely, large-scale (tectonic) fractures limit stimulation efficiency and pose environmental/induced seismicity risks. Therefore, stimulation-driven reactivation of small-scale fractures facilitates drainage and enhances well productivity. Relatedly, reservoir flow regimes and production decline curves are intricately controlled by interplay of natural fracture density and matrix permeability. Variability of these parameters calls for acreage-tailored stimulations.

Abstract In Mississippi, USA, exposures of fossiliferous Cretaceous and Paleogene strata contributed to geological investigations for more than 200 years. Since 2012, four Mississippi fossiliferous field sites were regularly integrated within university palaeontology classrooms, with community engaged learning (CEL) introduced in 2018. Through CEL projects, the students assisted local organizations with optimizing and/or protecting local fossiliferous sites. Analysis of student surveys demonstrated that students were overwhelmingly positive toward local field sites and CEL inclusion in the palaeontology courses. Students acknowledged ‘real-world’ interdisciplinary CEL experiences moved them beyond the palaeontology content and made them stakeholders in modern issues. While these four sites contain landscapes that qualify as local geoheritage sites because of their educational and potential geotourism value, only one site, W.M. Browning Cretaceous Fossil Park, is preserved for future generations. The other sites (Blue Springs, Osborn Prairie, Smith County) face challenges in their long-term sustainability.