Fracturing with Carbon Dioxide: From Microscopic Mechanism to Reservoir Application

The quest for efficient recovery of unconventional oil and gas has led to the widespread adoption of water fracturing. Despite its effectiveness, this method has significant drawbacks including substantial water usage and ensuing environmental repercussions. Recognizing these challenges, CO2 fracturing has emerged as a potential alternative that could mitigate some of these concerns and additionally offer benefits such as carbon sequestration and enhanced oil recovery.

Utilizing specially crafted equipment and cutting-edge analytical techniques, our study offers a comprehensive multiscale examination of the fracturing mechanics and behavior differences between CO2 and water. The findings suggest that CO2's inherent properties, especially its high leak-off rate, prompt the creation of shear fractures. These, in turn, pave the way for the formation of tensile and mixed fractures, resulting in intricate fracture networks and an increased stimulated reservoir volume. Such advantages, when applied in real-world scenarios, translated to a remarkable 4- to 20-fold surge in tight oil production in five test wells, demonstrating the potential superiority of CO2 fracturing over its water-based counterpart.