Do Shale Pore Throats Have a Threshold Diameter for Oil Storage?

Area of Science:

• Petroleum Geoscience
• Nanotechnology
• Surface Chemistry

Background:

• Shale oil reservoirs are complex systems with pore structures influencing oil storage and recovery.
• Understanding nanoscale fluid flow and wetting phenomena is crucial for accurate reservoir characterization.
• Existing methods for estimating shale oil reserves may not fully account for pore-scale storage limitations.

Purpose of the Study:

• To investigate the effect of pore throat diameter on oil storage capacity in shale formations.
• To determine the minimum pore throat size required for effective oil storage at the nanoscale.
• To establish new criteria for evaluating shale oil reserves based on pore structure.

Main Methods:

• Utilized a nanoporous template with controllable channel diameters to simulate shale pore throats.
• Examined oil seepage in nano-channels of varying diameters.
• Analyzed nanoscale solid-liquid interface wetting behaviors to understand fluid dynamics.

Main Results:

• Identified a lower threshold of 20 nanometers for pore throat diameter essential for shale oil storage under specific conditions.
• Demonstrated a systematic relationship between pore diameter and oil storage capacity.
• Provided quantitative data on oil seepage influenced by pore size and wetting properties.

Conclusions:

• The 20nm pore throat size threshold offers a novel, evidence-based criterion for estimating geological, recoverable, and economically recoverable shale oil reserves.
• This research enhances the understanding of oil storage mechanisms within shale nanopores.
• The findings have the potential to significantly impact the shale oil industry by improving reserve estimations and recovery strategies.