Comparison of reservoir characteristics between continental shale from faulted basin and marine shale under high-over mature stage: Taking Shahezi Formation in Xujiaweizi faulted basin and Longmaxi Formation in Sichuan Basin as an example
ZHAO Renwen, XIAO Dianshi, LU Shuangfang, et al. Comparison of reservoir characteristics between continental shale from faulted basin and marine shale under high-over mature stage: Taking Shahezi Formation in Xujiaweizi faulted basin and Longmaxi Formation in Sichuan Basin as an example[J]. Petroleum Reservoir Evaluation and Development, 2023, (1): 52-63+99.
ZHAO Renwen, XIAO Dianshi, LU Shuangfang, et al. Comparison of reservoir characteristics between continental shale from faulted basin and marine shale under high-over mature stage: Taking Shahezi Formation in Xujiaweizi faulted basin and Longmaxi Formation in Sichuan Basin as an example[J]. Petroleum Reservoir Evaluation and Development, 2023, (1): 52-63+99. DOI: 10.13809/j.cnki.cn32-1825/te.2023.01.006.
Gas bearing shale is widely developed in continental faulted basins in China. In the past
it was mainly studied as the gas source rock
and there was little research on its reservoir and influencing factors. It is urgent to carry out corresponding researches to clarify the main controlling factors of shale reservoir development in continental faulted basins. For the researches
the shale of Shahezi Formation in Xujiaweizi fault depression of Songliao Basin and Longmaxi Formation in Sichuan Basin are selected
and the difference of reservoir characteristics between high over mature continental fault depression basin and marine gas shale is compared and studied by the experiments such as organic geochemistry
whole rock analysis
scanning electron microscope
low-temperature nitrogen adsorption and nuclear magnetic resonance. The research shows that the shale formation environment of Shahezi Formation is diverse
the organic matter type is mainly type Ⅲ
the clay mineral content is high
the cemented quartz is developed
the clay related pores and quartz intergranular pores are the main pore types
the specific surface area is small but the pore diameter is large
and the reservoir development is controlled by compaction
clay mineral transformation and coal seam development; Longmaxi Formation shale was formed in shelf environment. The type of organic matter is mainly type Ⅰ
with high abundance of organic matter and high content of biogenic quartz. Organic pores and clay related pores are the main pore types
and the type and maturity of organic matter mainly control the development of pores. On the whole
the shale reservoir development conditions of Shahezi Formation are slightly worse than those of Longmaxi Formation
but the plain swamp microfacies shale is developed close to the coal seam
the authigenic cemented quartz is developed
the proportion of Yimeng mixed layer is high
the reservoir has high organic matter abundance
good compressibility
large pore volume and specific surface area and good porosity development
which can be used as a potential favorable target for further evaluation and research.