The Early Silurian Sedimentary Environment of Middle-Upper Yangtze: Lithological and Palaeontological Evidence and Impact on Shale Gas Reservoir
| Autor: | Yang Wang, Yanming Zhu, Fuhua Shang, Xiaorong Qu |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Provenance
graptolite lcsh:QE351-399.2 0211 other engineering and technologies Geochemistry 02 engineering and technology Structural basin 010502 geochemistry & geophysics 01 natural sciences Sedimentary depositional environment 021108 energy Porosity Tight gas 0105 earth and related environmental sciences Total organic carbon lcsh:Mineralogy biozonation Geology Lomgmaxi Formation Geotechnical Engineering and Engineering Geology lithological characteristics Longmaxi Formation Middle-Upper Yangtze Sedimentary rock Oil shale |
| Zdroj: | Minerals, Vol 9, Iss 8, p 494 (2019) Minerals Volume 9 Issue 8 |
| Popis: | The organic-enriched thick shale at the bottom of Longmaxi Formation is laterally continuous distributed and has been proven to be of good production capability in Fuling of Upper Yangtze. Uplifts that developed during the sedimentation influenced the reservoir characteristics by taking control of the sedimentary environment and provenance. The sedimentary environments are mainly deep-water shelf, shallow-water shelf, and tidal flat. By analyzing reservoir characteristic of these three environments, the deep-water shelf, which dominated the early stage of sedimentation, formed a high-quality reservoir with high TOC (Total Organic Carbon) content, porosity, and brittleness, while the environment was maintained around the basin centre until the Early Silurian. The shales deposited under the shallow-water environment were of low porosity because of the increasing calcareous and argillaceous contents. Sediments which formed on the tidal flat were arenaceous and of the lowest TOC content as the organic preservation conditions deteriorated. The good correlation of graptolite abundance and TOC content, and high porosity within graptolite fossils emphasize the importance of palaeontological development. The argillaceous cap over the Longmaxi shale is of good sealing capability, and the continuous sedimentation zone along southern Sichuan&ndash eastern Chongqing is the best optimized hydrocarbon-bearing system. However, a weak interface on the discontinuity is the potential lateral pathway for gas diffusion at Northern Guizhou and Western Hunan, but on the southeast margin where the dark shale and the tidal sandstone contact, it promises to form a tight gas reservoir. |
| Databáze: | OpenAIRE |
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