1D Joint inversion of frequency-domain and time-domain MCSEM data in marine shallow waters
Yue Mingxin1,2,3, Wu Xiaoping1,3
1. Laboratory of Seismology and Physics of Earth's Interior, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China;
2. Key Laboratory of Exploration Technologies for Oil and Gas Resources, Yangtze University, Ministry of Education, Wuhan, Hubei 430100, China;
3. Mengcheng National Geophysical Observatory, Mengcheng, Anhui 233500, China
Abstract:1D forward modeling of marine electromagne-tic (MCSEM) data shows that both frequency-domain data and time-domain data have certain limitations when using a horizontal electric dipole as the emission source in shallow water. In order to better use MCSEM for offshore oil and gas exploration,we have acquired frequency-domain and time-domain data at the same time based on the idea of the time-frequency electromagnetic (TFEM) method used on land. We achieve 1D joint inversion of time-domain and frequency-domain electromagnetic data with the regularization inversion method. According to our model data tests,for a deep reservoir model with 300 m water depth,inverted frequency-domain data can show reservoir location and resistivity,but additional time-domain data cannot improve resolution; for a deep reservoir model with 100m water depth,joint inversion results are better than that of a single domain data set.
Constable S,Srnka L J.An introduction to marine controlled-source electromagnetic methods for hydrocarbon exploration. Geophysics,2007,72(2):WA3-WA12.
[2]
Constable S. Ten years of marine CSEM for hydrocarbon exploration. Geophysics,2010,75(5):A67-A81.
[3]
何展翔,余刚.海洋电磁勘探技术及新进展.勘探地球物理进展,2008,31(1):2-9.
He Zhanxiang,Yu Gang. Marine EM survey techno-logy and its new advances. Progress in Exploration Geophysics,2008,31(1):2-9.
[4]
何展翔,孙卫斌,孔繁恕等.海洋电磁法.石油地球物理勘探,2006,41(4):451-457.
He Zhanxiang,Sun Weibin,Kong Fanshu et al. Marine electromagnetic approach.OGP,2006,41(4):451-457.
[5]
Weiss C J. The fallacy of the "shallow-water problem" in marine CSEM exploration. Geophysics,2007,72(6):A93-A97.
[6]
Edwards R N,Chave A D. A transient electric dipole-dipole method for mapping the conductivity of the sea floor.Geophysics,1986,51(4):984-987.
[7]
Cheesman S J,Edwards R N,Chave A D. On the theory of sea-floor conductivity mapping using transient electromagnetic systems. Geophysics,1987,52(2):204-217.
Study on joint inversion method of one-dimensional time-domain magnetic field and frequency-domain electric field.Progress in Geophysics,2011,26(6):2011-2017.
[14]
Stoyer C H.Electromagnetic fields of dipoles in stra-tified media. IEEE Transactions on Antennas and Propagation,1977,25(4):547-552.
[15]
Guptasarma D,Singh B. New digital linear filters for Hankel J0 and J1 transforms. Geophysical Prospecting,1997,45(5):745-762.
[16]
王华军.正余弦变换的数值滤波算法.工程地球物理学报,2004,1(4):329-335.
Wang Huajun. Digital filter algorithm of the sine and cosine transform. Chinese Journal of Engineering Geophysics,2004,1(4):329-335.
[17]
Tikhonov A N and Arsenin V I A. Solutions of Ill-posed Problems. Winston,Washington DC,1977.
[18]
Constable S C,Parker R L,Constable C G. Occam's inversion:A practical algorithm for generating smooth models from electromagnetic sounding data. Geophysics,1987,52(3):289-300.
[19]
Key K.1D inversion of multicomponent,multifre-quency marine CSEM data:Methodology and synthe-tic studies for resolving thin resistive layers. Geophy-sics,2009,74(2):F9-F20.
Dai Yijun,Tang Wenwu and Cao Chuanghua. Time-frequency joint inversion in electromagnetic method of horizontal layered medium. Computing Techniques for Geophysical and Geochemical Exploration,2013,35(1):18-22.