Reservoir space of the Es33–Es41 shale in Dongying sag

The Es33–Es41 shales in Dongying sag are source rocks with large reserves of shale oil and gas. For the identification of development characteristics and geological significance of the reservoir space, FMI logging, core observation, thin section analysis, X-ray diffraction, fluorescence microscopy, scanning electron microscopy, mercury porosimetry, low-temperature nitrogen adsorption, atomic force microscopy, and conventional physical property testing were used to study the petrology and reservoir space of the Es33–Es41 shale in Dongying sag. The results suggest that the shale is rich in carbonate minerals. Phanerocrystalline stratiform and lamellar argillaceous limestone and calcareous claystone are the oil- and gas-bearing lithofacies. The oil in the micropores is mainly present as membranes and clots. The shale reservoir space has a network structure with veins, carbonate and clay minerals, and micropores among pyrite and the matrix. The results provide the geological framework for future shale oil and gas exploration in Dongying sag.