Differences in Pore Type and Pore Structure between Silurian Longmaxi Marine Shale and Jurassic Dongyuemiao Lacustrine Shale and Their Influence on Shale-Gas Enrichment

The Silurian Longmaxi (S1l) marine shale and Jurassic Dongyuemiao (J1d) lacustrine in the Sichuan Basin, West China have attracted considerable attention from oil-and-gas industry China. Currently, differences pore types structures between them are poorly understood, which has limited shale-resource exploration Basin. This paper systemically compares characteristics of investigates their impact on shale-gas enrichment by integrating field-emission scanning electron microscopy (FE–SEM), X-ray diffraction (XRD), low-pressure gas (CO2 N2) adsorption mercury-intrusion porosimetry, high-pressure sorption isotherms, gas-saturation measurement, molecular-dynamics simulation, etc. results show that S1l organic-rich J1d different structures. is dominated organic pores, mainly micropores mesopores with ink-bottle-like shapes, while primarily composed clay-mineral macropores slit- or plate-like shapes. Organic pores can provide storage space for shale, also determines capacity reservoirs. Although not most prevalent they play an important role enhancing reservoir quality absorbed-gas enrichment. Clay-mineral contribute weakly to J1d-lacustrine-shale Mesopores form both contributing significantly Micropores secondary importance contributors volume shale.