Work

Formation Mechanisms of Laminae in Continental Shales and Their Controls on Differential Shale Oil Enrichment

Year: 2026

Type: article

Abstract: Laminae are fundamental structural units of heterogeneity in continental shales and significantly influence organic matter accumulation, hydrocarbon generation and retention, reservoir evolution, fluid redistribution, and fracture propagation. This review critically synthesizes evidence from representative lacustrine shale systems in the Jiyang Depression and Cangdong Sag of the Bohai Bay Basin, as well as the Ordos, Junggar, and Songliao basins, together with selected lacustrine successions worldwide. Lamina development reflects the coupled effects of terrigenous supply, aquatic productivity, authigenic mineral precipitation, hydrodynamic conditions, water-column stratification, and early preservation. Climatic change and astronomical forcing affect these processes indirectly, and their sedimentary expression varies among basins. Depositional heterogeneity is subsequently modified by compaction, cementation, dissolution, mineral transformation, hydrocarbon generation, and fracture development, producing lamina-scale differences in generation, storage, mobility, and mechanical behavior. Available petrographic, geochemical, petrophysical, and experimental evidence indicates that shale oil is dominated by in situ retention, accompanied by conditional short-distance redistribution between adjacent laminae through connected pores, interfaces, and microfractures. However, migration distance, flux, and associated compositional fractionation remain poorly quantified. Accordingly, an evidence-based conceptual framework linking lamina formation, differential hydrocarbon generation, heterogeneous storage, in situ retention and short-distance redistribution, enrichment in favorable units, and fracture connectivity is proposed. This framework integrates processes commonly addressed separately and distinguishes established relationships from basin-specific observations and conceptual interpretations.

Source: Processes

DOI: 10.3390/pr14203271

Authors: Yinmei Wang, Shang Xu, Qiyang Gou

Institution: China University of Petroleum, East China

Language: English

Topic: Hydrocarbon exploration and reservoir analysis

Subfield: Mechanics of Materials

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,896

Funder: National Natural Science Foundation of China