Making sense of micro-fractures to the Longmaxi shale reservoir quality in the Jiaoshiba area, Sichuan Basin, China: Implications for the accumulation of shale gas

The processes of shale gas transport and enrichment are closely related to the micro-fractures structure. Here, porosity, permeability test, adsorption, scanning electron microscopy (SEM), fluid spontaneous imbibition, Nano-CT, Micro-CT, core observations were used determine types characteristics in Longmaxi shales, Jiaoshiba area. effects on reservoir properties accumulation also analyzed. Diverse sizes intra-particle (intraP), particle-edge, transparticle widely developed shales. difference micro-fracture was mainly controlled by mineral composition. well-developed shales can act as a “bridge” link nano-pores macro-fractures. In such cases, large-scale “escape network” composed “nano-pores, micro-fractures, macro-fractures” formed. escape hydrocarbons along this network results lower pore pressure. Most pores dramatically compressed due compaction overlying strata. As result, space seepage capacity organic-rich disappointed, which is not benefit production gas. However, limited development will reduce probability forming network”. Thus, some could be remained storage with for even within tectonically deformed