Energies, Vol. 18, Pages 4845: Induced Fractures and Production Behavior by Fracturing-Flooding in Tight Oil Formations

Energies, Vol. 18, Pages 4845: Induced Fractures and Production Behavior by Fracturing-Flooding in Tight Oil Formations

Energies doi: 10.3390/en18184845

Authors:
Jinshan Xu
Yonggang Yi
Xiang Dai
Xudong Luo
Tao Wan

Conventional hydraulic fracturing aims to minimize the loss of fracturing fluid, with the fluid serving solely to generate fractures, whereas the fracturing-flooding process involves the injection of an agent that facilitates fracture generation without flowing back. This injection agent not only acts as a fracturing treatment but also engages in a displacement process. Currently, there exists a notable gap in systematic research concerning the mechanisms of production enhancement via fracturing-flooding. The characterization of the flow pattern and production behavior associated with fracturing-flooding remains unclear. By integrating physical laboratory experiments with numerical simulations, this study finds that an increase of the displacement pressure gradient can increase the matrix permeability by 10–20%. The residual oil distribution also transfers from a contiguous state to an oil film. It results in a smaller pore–throat size, so oil can be mobilized. Stepwise reduced rate injection leverages the advantages of short-wide fractures while enhancing lateral fracture complexity and oil production rates. Furthermore, we aim to quantitatively characterize the fractures resulting from fracturing-flooding at the microscale and to establish a physical simulation methodology for low-permeability sandstone.