In recent years, unconventional oil and gas reservoirs have received extensive attention and have played a significant role in satisfying growing energy demands. Compared with conventional reservoirs, unconventional reservoirs are characterised by low porosity and ultra-low permeability, and therefore conventional theories and approaches are typically not applicable to fluid flow in these reservoirs. Understanding fluid flow and transport dynamics in unconventional reservoirs is crucial for reservoir formation evaluation and for predicting gas production.

Due to the complex pore structures and distinctive storage in unconventional rocks, multiphase flow in low-permeability unconventional reservoirs is a complex process, and there are many challenges in the fundamental theories and techniques used to describe and model fluid flow and transport in unconventional reservoirs. Therefore, new multi-scale and multi-physical methods and technologies are being continuously developed to characterise unconventional reservoirs and to describe flow and transport dynamics within them.

This Special Issue aims to present recent advances in various subjects addressing difficulties in the development of unconventional resources. We invite investigators to contribute original research articles that will explore as many aspects as possible in modelling fluid flow and characterisation of unconventional reservoirs. We welcome both original research and review articles.

Potential topics include but are not limited to the following:

• Modelling and characterisation of flow behaviours in unconventional formation
• Multi-phase flow modelling and characterisation
• New advances in hydraulic fracturing techniques
• Oil and gas flow simulation considering multiple mechanisms
• Pressure/rate transient behaviours in fractured porous media
• Flow and transfer dynamics in unconventional reservoirs
• Multi-scale reservoir simulation techniques
• Artificial intelligence aided research in unconventional reservoir development
• Field cases and novel finding of flow behaviours in unconventional reservoirs