Development characteristics of multi-scale fracture network systems in metamorphic buried hills

Natural fractures are regarded as important reservoir spaces and effective seepage channels at metamorphic buried hills. Continuous networks associated with multi-scale good connectivity is critical for high-quality reservoirs well high stable production in the tight rocks. The Bozhong 19–6 hills were characterized through integrating image logs, cores, thin-sections, scanning electron microscope, etc. After that, power-law distribution of was established to understand contribution quality figure out structure models fracture their impact on production. Results show that parameters systems vary regularly scales. Fracture development degree, e.g., cumulative areal density, increases a power law function decreasing size from macro micro (e.g., aperture and/or length), where storage space also increased. Reversely, permeability follow significant trend. Five network based combination pattern fractures: high-density multi-sets, large-scale medium-density small-scale low-density single-set. former two can be widely developed into reservoirs, contributing greatly yields. Fracturing required third fourth obtain production, while it difficult fifth industrial oil gas flow.