Porosity-preserving mechanisms of marine shale in Lower Cambrian of Sichuan Basin, South China

These observations suggest that brittle mineral grains can function as rigid frameworks or grain supporters due to high brittleness which preserves ductile matrix relating pores (OM-hosted pores and clay associated pores) from collapse by sharing the effective stress; in addition, either excessive OM abundance (TOC>5.0 wt%) or over thermal maturity (Ro>3.3%) is detrimental to pore preservation; moreover, poor sealing ability of shale systems might deteriorate pore preserving ability through losing overpressure environment or stress supporting mechanism.