Deep shale gas in the Ordovician-Silurian Wufeng–Longmaxi formations of the Sichuan Basin, SW China: Insights from reservoir characteristics, preservation conditions and development strategies

Rare Earth Element Characteristics of Shales from Wufeng–Longmaxi Formations in Deep-Buried Areas of the Northern Sichuan Basin, Southern China: Implications for Provenance, Depositional Conditions, and Paleoclimate

“…The end of the Ordovician and the beginning of the Silurian was an important period in Earth history, − and it is marked by marine mass extinction, large-scale glaciation, sea-level change, extensive volcanism, ocean anoxic event, and extensive deposition of marine black shale. − Black marine shale, as a source rock for oil and gas, is widely accumulated in paleogeographic environments. − To this day, such a black shale has been widely developed as unconventional reservoirs in many countries, such as the United States, Canada, Australia, China, Germany, Russia, etc. − Thus, the study of the sedimentary environment and the mechanism of organic matter accumulation for the marine shales of the Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation in the northern Sichuan Basin not only can provide important information about the climatic and paleoenvironmental change of the Ordovician–Silurian but also provides evidence for the prediction of favorable areas for oil and gas exploration.…”

Organic matter characteristics and gas generation prospect of the Late Cretaceous fluvial deltaic organic‐rich shale in the offshore Jiza‐Qamar Basin, Yemen based on organic geochemical, macerals composition, and biomarker results combined with 1‐D basin modelling

“…Both marine and continental oil‐ and gas‐shale source rocks have been successfully explored and developed worldwide, showing remarkable potential. The knowledge of geology, lithofacies, and organic matter (OM) characteristics of these shales seriously limits gas and oil exploration in any sedimentary basin (Hill et al, 2007; Katz & Lin, 2021; Nie et al, 2023). Multi‐integrated techniques are vital to the study of shale source rock systems where organic geochemistry, microscopic examination, and biomarker measurements combined with 1‐D basin modelling can be used to evaluate the OM characteristics and their ability to generate gas and their recoverable estimates in sedimentary basins (Jarvie et al, 2007; Mahdi et al, 2022; Radwan et al, 2022).…”

Characteristics and Model of Heterogeneous Wettability in a Marine-Continental Transitional Shale Reservoir: Insights from Organic Matter, Minerals, and Microstructure

“…Wetting is a universal physical phenomenon with important effects on hydrocarbon reservoir evaluation and development. − The remarkable success of marine overpressure shale gas development in China has stimulated an exploration boom and is encouraging investigation into deep shale gas (with burial depth greater than 3500 m) and normal-pressure shale gas (with formation pressure coefficient generally less than 1.2). − The wettability of porous rocks can reflect many properties such as the fluid–rock interfacial tension, fluid activity, remaining oil saturation, effectiveness of water flooding, and petrophysical properties. − However, unconventional shale reservoirs have a highly heterogeneous composition, complex pore-fracture structures, and ultralow porosity and permeability, with the result that the study of shale wettability is more challenging than conventional reservoirs. Therefore, an understanding of shale heterogeneous wettability is important for oil and gas exploration and utilization. , …”