1. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China
2. Resource Geophysics Academy, Imperial College London, London, SW7 2BP, UK
3. College of Earth Sciences, Hebei GEO University, Shijiazhuang,050031, China
4. Department of Earth Science and Engineering, Imperial College London, London, SW7 2BP, UK