| Title | Pore evolution model and diagenetic evolution sequence of the Mesoproterozoic Xiamaling shale in Zhangjiakou, Hebei |
| Authors | Xu, Liangwei Yang, Keji Wei, Hao Liu, Luofu Jiang, Zhenxue Li, Xiao Chen, Lei Xu, Tong Wang, Ximeng |
| Affiliation | Peking Univ, Sch Earth Space Sci, MOE, Key Lab Orogen Belts & Crustal Evolut, Beijing 100871, Peoples R China Hebei GEO Univ, Hebei Key Lab Strateg Crit Mineral Resources, Shijiazhuang 050031, Hebei, Peoples R China China Univ Petr, State Key Lab Petr Resources & Prospecting, Beijing 102249, Peoples R China Hebei GEO Univ, Inst Explorat Technol & Engn, Shijiazhuang 050031, Hebei, Peoples R China |
| Keywords | BOHAI BAY BASIN ORGANIC-RICH MARINE SHALE GAS ADSORPTION LITHOFACIES MUDSTONES MUDROCKS POROSITY REGION |
| Issue Date | Dec-2021 |
| Publisher | JOURNAL OF PETROLEUM SCIENCE AND ENGINEERING |
| Abstract | Current research on diagenesis and its evolution focuses mainly on sandstone reservoirs. Conventional oil and gas reservoir observation techniques for characterizing shale reservoirs are limited, and comprehensive research on nanoscale pore variations, diagenesis and evolution of shale reservoirs, especially immature and low-maturity marine shale reservoirs, is relatively scarce. To reveal the diagenesis and evolution of low-maturity marine shale, geochemical and mineral analyses, quantitative characterization of the pore structure and qualitative characterization of the pore morphology were performed on the Xiamaling shale. With the burial and geothermal history, the Xiamaling diagenetic evolution sequence and the nanoscale pore system evolution were studied. The results show that smectite continually transforms to an illite-smectite (I/S) mixed layer and then quickly transforms to illite and chlorite; the kaolinite content gradually decreases as maturity increases. The hydrocarbon expulsion threshold of the Xiamaling shale is EqRo = 1.0%, and the porosity decreases to a minimum value of EqRo = 1.0% and then increases. The pore structure evolution model shows that the pore volumes (PVs) of micropores and macropores decrease to minima at approximately EqRo = 0.92% and 0.85%, respectively, and then increase; the mesopore PVs continuously decrease. Micropore and mesopore surface areas (SAs) decrease to their minima at approximately EqRo = 0.85% and 1.0%, respectively, and then increase; simultaneously, the macropore SAs continuously decrease. The main diagenetic types of the Xiamaling shale are compaction, dissolution, cementation, thermal maturation of organic matter (OM), and clay mineral transformation; it reaches period B of the middle diagenetic stage, and the diagenetic evolution sequence is determined. The pore system composition and variation characteristics of the Xiamaling shale are analysed, and a corresponding evolution model is established. |
| URI | http://hdl.handle.net/20.500.11897/623976 |
| ISSN | 0920-4105 |
| DOI | 10.1016/j.petrol.2021.109115 |
| Indexed | SCI(E) |
| Appears in Collections: | 造山带与地壳演化教育部重点实验室 |
