Fracability Evaluation of Shale of the Wufeng-Longmaxi Formation in the Changning Area, Sichuan Basin
Cheng HUANG
Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049 China
Search for more papers by this authorTianyang XU
Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049 China
Search for more papers by this authorCorresponding Author
Yiwen JU
Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049 China
Corresponding author. E-mail: [email protected]Search for more papers by this authorHongjian ZHU
Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049 China
Search for more papers by this authorLiting JU
Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049 China
Search for more papers by this authorWuyang LI
Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049 China
Search for more papers by this authorCheng HUANG
Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049 China
Search for more papers by this authorTianyang XU
Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049 China
Search for more papers by this authorCorresponding Author
Yiwen JU
Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049 China
Corresponding author. E-mail: [email protected]Search for more papers by this authorHongjian ZHU
Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049 China
Search for more papers by this authorLiting JU
Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049 China
Search for more papers by this authorWuyang LI
Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049 China
Search for more papers by this authorAbout the first author:
HUANG Cheng, male, born in 1992 in Luoyang city, Henan Province. Now he continues his study at University of Chinese Academy of Sciences as a PhD candidate, and his current research focuses on shale gas reservoir and structural geology. E-mail: [email protected]; phone: 18401697647.
About the corresponding author:
JU Yiwen, male, born in 1963 in Tongcheng city, Anhui Province. He is a professor of Geology and doctoral supervisor at the University of Chinese Academy of Sciences. His main interests focus on structural geology and energy basin geology, unconventional energy geology, coal and gas geology, and nanogeology. E-mail: [email protected]; phone: 010–88256466.
Abstract
The fracturing technology for shale gas reservoir is the key to the development of shale gas industrialization. It makes much sense to study the mechanical properties and deformation characteristics of shale, due to its close relationship with the fracability of shale gas reservoir. This paper took marine shale in the Changning area, southern Sichuan Basin of China as the research object. Based on field profile and hand specimen observation, we analyzed the development of natural fractures and collected samples from Wufeng Formation and Longmaxi Formation. Combining with the indoor experiment, we investigated the macroscopic and microscopic structural features and the remarkable heterogeneity of shale samples. Then we illustrated the mechanics and deformation characteristics of shale, through uniaxial compression test and direct shear test. The shale has two types of fracture modes, which depend on the angular relation between loading direction and the bedding plane. Besides, the Wufeng shale has a higher value of brittleness index than the Longmaxi shale, which was calculated using two methods, mechanical parameters and mineral composition. Given the above results, we proposed a fracability evaluation model for shale gas reservoir using the analytic hierarchy process. Four influence factors, brittleness index, fracture toughness, natural fractures and cohesive force, are considered. Finally, under the control of normalized value and weight coefficient of each influence factor, the calculations results indicate that the fracability index of the Wufeng Formation is higher than that of the Longmaxi Formation in Changning area, southern Sichuan Basin.
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