Digital image correlation analysis of the rapid reduction mechanism of permeability in low-permeability sandstone reservoirs

ABSTRACT

Low-permeability sandstone reservoirs play a great role in the exploration and production of oil and gas resources, but most of them undergo a rapid reduction in permeability at the beginning of the production process and exhibit a depleted production rate as time progresses. To discern the rapid reduction mechanism of permeability, an experimental study was performed using low-permeability sandstone specimens. Using a digital image correlation method, a binary image process was used to capture fluid flow passage through microscopic pore structures. Combined with a laser engraving technique, a simplified displacement experiment was conducted, and it was found that the rapid reduction in permeability was caused by loose grain particles, which can be transferred with the fluid and thus block the pore throats. These preliminary findings can provide guidance for improving the production prediction accuracy and understanding of the rapid depleted production rate at the beginning of the production history.

KEYWORDS:

• Low-permeability sandstone reservoirs
• pore structures
• laser engraving
• binary image
• digital image correlation
• permeability reduction

Additional information

Funding

This study was supported by the National Natural Science Foundation of China (Grant No. 51304032, Grant No. 51674044), the Opening fund of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (No. PLC201609) and the National Science and Technology Major Project (Grant No. 2016ZX05023-001).