A novel pore-fracture dual network modeling method considering dynamic cracking and its applications

Abstract

Unconventional reservoirs are normally characterized by dual porous media, which has both multi-scale pore and fracture structures, such as low permeability or tight oil reservoirs. The seepage characteristics of such reservoirs is mainly determined by micro-fractures, but conventional laboratory experimental methods are difficult to measure it, which is attribute to the dynamic cracking of these micro-fractures. The emerging digital core technology in recent years can solve this problem by developing an accurate pore network model and a rational simulation approach. In this study, a novel pore-fracture dual network model was established based on percolation theory. Fluid flow in the pore of two scales, micro-fracture and matrix pore, were considered, also with the impact of micro-fracture opening and closing during flow. Some seepage characteristic parameters, such as fluid saturations, capillary pressure, relative permeabilities, displacement efficiency in different flow stage, can be predicted by proposed calculating method. Through these work, seepage characteristics of dual porous media can be achieved.

Keywords

• Pore-fracture dual network model
• Micro-fracture
• Dynamic cracking
• Digital core
• Dimensionless parameters
• Seepage characteristics