科研之友
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摘要
The black shale of the lower Sinian (Neoproterozoic) Doushantuo Formation, located in the Yangtze area (Hubei, China), has a great potential to contain shale gas. The main depositional environments of the region included tidal flats, shelf lagoons, shelf margins, and slopes. While black shale formed from deposits in a shelf lagoon setting, the sediments from the tidal flats were dolomitic. Several factors affect the sediments deposited in these environments, including sediment surface energy (i.e., quiescent or turbulent), salinity, and the presence of either oxic or reducing conditions. The depositional environments of segments B and D of the Doushantuo Formation in the Jiulongwan section were significantly different; specifically, segment D was anoxic to euxinic. As a result, the total organic carbon (TOC) in the segment D shale is higher than that in segment B. This study also used field emission scanning electron microscopy to show that pores in organic matter are the main gas storage space and that the organic matter pores in segment D have diameters less than 100 nm. The increasing of the organic matter content increases organic pore and porosity of the reservoir. TOC is not only the main controlling internal factors of the micropores of the shale in Doushantuo Formation but also provides the important storage space for shale gas. The quiet and hypoxia environment of the black shale in Doushantuo Formation is the main factor controlling the enrichment of organic matter, and the enrichment of organic matter is beneficial to improve the physical property of the shale reservoir. Therefore, black shale formed in the quiet and anoxic depositional environment has better reservoir physical property.
- 出版日期2016-5
- 单位成都理工大学
