Induced Fractures and Production Behavior by Fracturing-Flooding in Tight Oil Formations

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.