| Summary: | Based on rock mineral and geochemical analysis, microscopic observation, physical property measurement, and thin laminae separation test, etc., the characteristics of typical laminae of the Paleogene Shahejie Formation carbonate-rich shale in the Jiyang Depression were analyzed, and the organic matter abundance, reservoir properties, and oil-bearing properties of different laminae were compared. Typical shale reservoir-flow structures were classified, and the mobility of oil in different types of shale reservoir-flow structure was compared. The results show that the repeated superposition of mud laminae and calcite laminae are the main layer structure of carbonate-rich shales. The calcite laminae are divided into micritic calcite laminae, sparry calcite laminae and fibrous calcite vein. The mud-rich laminae are the main contributor to the organic matter abundance and porosity of shale, with the best hydrocarbon generation potential, reservoir capacity, and oil-bearing property. The micritic calcite laminae also have relatively good hydrocarbon generation potential, reservoir capacity and oil-bearing property. The sparry calcite laminae and fibrous calcite vein have good permeability and conductivity. Four types of shale reservoir-flow structure are developed in the carbonate-rich shale, and the mobility of oil in each type of reservoir-flow structure is in descending order: sparry calcite laminae enriched shale reservoir-flow structure, mixed calcite laminae enriched shale reservoir-flow structure, fibrous calcite vein enriched shale reservoir-flow structure, and micritic calcite laminae enriched shale reservoir-flow structure. The exploration targets of carbonate-rich shale in the Jiyang Depression Shahejie Formation are different in terms of reservoir-flow structure at different thermal evolution stages.
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