Controls of zeolite development on reservoir porosities from Lower Permian Formations in Shawan and its adjacent areas, western Junggar Basin

The genesis and evolutionary patterns of zeolite cements result in diverse pore types, complex compositions, and significant heterogeneity in reservoirs. To investigate their impact on pores, this study integrates core observations, thin-section petrography, scanning electron microscopy (SEM), whole-rock X-ray diffraction (XRD), and energy-dispersive spectroscopy (EDS) for macro-micro comparative analysis of zeolite cement types, formation mechanisms, and pore systems in the Lower Permian strata of the Shawan Sag and adjacent areas. Research demonstrates that provenance differences control zeolite cement types and origins: In the Shawan Sag, zeolites form through hydration of volcanic glass in tuff, while adjacent areas develop zeolites via albitization of plagioclase. This genetic divergence drives pore differentiation: Zeolite evolution in the Sag generates grain-edge fractures through cement density changes and crystalline water release, whereas dissolution of laumontite and calcite in adjacent areas develops dissolution-dominated pores.