Application of a wide-field electromagnetic method to shale gas exploration in South China
Yang Xue-Li1, Li Bo1, Peng Chuan-Sheng1, and Yang Yang2
1. China Huadian Engineering Co., LTD, Beijing 100160, China.
2. School of Geoscience and Info-Physics, Central South University, Changsha 410083, China.
Abstract：
In an effort to reduce the shale gas exploration risks and costs, we applied the wide-field electromagnetic method (WFEM), because of its strong anti-interference capability, high resolution, ability to conduct exploration at large depths, and high efficiency, to the Bayan Syncline in the South Huayuan block, Hunan Province. We collected rock samples and analyzed their resistivity and induced polarization (IP) and built A series of two-dimensional models for geological conditions to investigate the applicability of WFEM to different geological structures. We also analyzed the correlation between TOC of shale and the resistivity and IP ratio to determine the threshold for identifying target formations. We used WFEM to identify the underground structures and determine the distribution, depth, and thickness of the target strata. Resistivity, IP, and total organic carbon were used to evaluate the shale gas prospects and select favorable areas (sweet spots) for exploration and development. Subsequently, drilling in these areas proved the applicability of WFEM in shale gas exploration.
. Application of a wide-field electromagnetic method to shale gas exploration in South China[J]. APPLIED GEOPHYSICS, 2017, 14(3): 441-448.
[1]
Conti, J. J., Holtberg, P. D., and Beamon, J. A., et al., 2013, Annual Energy Outlook 2013 with Projections to 2040. US Energy Information Agency.
[2]
Di, Q., and Wang, R., 2008, CSAMT forward modeling and inversion and its application: Science Press, Beijing.
[3]
Goldstein, M. A., and Strangway, D. W., 1975, Audio-frequency magnetotellurics with a grounded electric dipole source: Geophysics, 40, 669−683.
[4]
He, J., 2010, Wide field electromagnetic sounding methods: Journal of Central South University, Science and Technology, 41, 1065−1072.
[5]
Tang, J., and He, J., 2005, Theory and application of CSAMT method: Central South University Press, Changsha.
[6]
Yin, C., and Piao, H., 1991, The definition of apparent resistivity in electromagnetic sounding methods: Geophysical & Geochemical Exploration, 15, 290−299.
[7]
Zhang, S., and Zhu, G., 2006, Gas accumulation characteristics and exploration potential of marine sediments in Sichuan Basin: Acta Petrolei Sinica, 27, 1−8.
[8]
Zhou, Q., Song, N., Wang, C., et al., 2014, Geological evaluation and exploration prospect of Huayuan shale gas block in Hunan Province: Natural Gas Geoscience, 25, 130−140.
[9]
Zonge, K. L., and Hughes, L. J., 1991, Controlled source audio-frequency magnetotellurics. Electromagnetic Methods in Applied Geophysics, Vol. 2, edited by Nabighian, M.N., 713−809. Society of Exploration Geophysicists.
2017, Vol. 14 
