Oil mobility evaluation and light hydrocarbon restoration in shale reservoirs: a review

Abstract

Organic matter-rich shale, a widely developed fine-grained sedimentary rock, hosts critical unconventional petroleum resources. Accurately assessing the resource potential and economic value of shale oil reservoirs is crucial for energy strategy decision-making, yet two challenges persist: evaluating oil mobility, and addressing light hydrocarbon evaporation. This study provides a review of these two critical dimensions. Laboratory testing forms the foundation of oil mobility assessment. In practice, method selection should be guided by the specific geological settings, data availability, and economic considerations. Notably, artificial intelligence offers the potential to generate accurate predictions even from limited datasets. This study establishes a generalizable framework validated through a case study on oil mobility evaluation under small-sample dataset scenarios. The second part divides the light hydrocarbon loss process from coring to experimental data acquisition into four distinct stages. The loss is continuously influenced by time-related degradation, with each stage characterized by different controlling factors. Nonetheless, the oil properties of shale and its own attributes remain consistent overarching influences. Minimizing additional losses through comprehensive and practical strategies represents the most effective solution. Future advances in experimental technologies, refined frameworks, and the deep mining and integration of data will enhance assessment accuracy. The findings of this study are expected to provide a solid theoretical foundation for the precise evaluation of resources in shale systems and the efficient delineation of prospective exploration targets.