Formation mechanisms of high‑quality ultra‑deep clastic reservoirs: Progress, scientific challenges and future directions

Abstract

As hydrocarbon exploration continues to advance into ultra‑deep formations, conventional theories of reservoir formation based primarily on compaction, pore preservation, and dissolution are increasingly being challenged. Growing exploration practice indicates that the formation of high‑quality ultra‑deep clastic reservoirs cannot be explained simply as a deeper continuation of conventional deep reservoir evolution. Instead, ultra‑deep reservoirs may represent a distinct geological regime, where reservoir evolution is governed by physical and chemical principles fundamentally different from those operating under conventional burial conditions. This work reviews the evolution of scientific understanding of reservoir formation in deep and ultra‑deep clastic reservoirs and identifies several fundamental scientific issues that remain unresolved. It is suggested that the formation of high‑quality ultra‑deep reservoirs should be interpreted as the evolution of an open reservoir‑forming system driven by the coupled interactions among the mass, thermal, pressure, stress, fluid, and chemical fields. Accordingly, the research paradigm is shifting from pore evolution toward the reservoir‑forming system. More importantly, this paradigm shift may provide the conceptual foundation for an emerging discipline of Ultra‑deep Reservoir Geology, offering a new theoretical framework for understanding, predicting, and evaluating high‑quality reservoirs in the ultra‑deep subsurface.

Document Type: Perspective 

Cited as: Li, H., Qu, X., Lin, J., Wang, W., Mishra, A., Ansah, E.O. Formation mechanisms of high‑quality ultra‑deep clastic reservoirs: Progress, scientific challenges and future directions. Advances in Geo‑Energy Research, 2026, 21(3): 201‑204. https://doi.org/10.46690/ager.2026.09.01