Linear and non-linear approximations based integral equation method in marine EM field modeling

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Abstract

Electromagnetic induction (EMI) methods have an important role in modeling hydrocarbon reservoirs embedded in marine sediments. One of these methods is marine control source electromagnetic (MCSEM) technique. In comparison with other geophysical techniques like seismic methods, which model hydrocarbon reservoir with high accuracy, The MCSEM technique is comparatively less accurate but due to much less costs, this method may be recommended for modeling hydrocarbon reservoirs embedded in marine sediments. In addition, the sea water reduces the voltage resulting from magnetotelluric (MT) currents, thus the MT method is not efficient, and is not suitable for imaging marine hydrocarbon reservoirs. Hence, the MCSEM method is used for these reservoirs. In this research, for three-dimensional (3D) forward modeling of a hydrocarbon reservoir with regular and irregular geometrical shape, and also, for four-dimensional (4D) forward modeling of a regular geometrical reservoir, integral equation (IE) method is used. The aim of the present study is to develop and apply several approximations to simulate the electromagnetic problems and to solve integral equation for 3D MCSEM synthetic data in order to avoid solving full integral equations, and also, to decrease the computational costs. In order to monitor small changes in electrical conductivity among increasing pressure inside the reservoir, the capability of time-lapse CSEM data has been discussed. It has been found that this method can detect the changes in the reservoir due to the fluid injection. In this study, T-matrix approximation (TMA), born approximation (BA) and extended born approximation (EBA) are applied to approximate 3-4D integral equations in the MCSEM method at low frequencies.

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References

بیات، م.، 1398، مدل‌سازی پیشرو داده‌های الکترومغناطیس دریایی با چشمه کنترل شده با استفاده از روش انتگرالی و با رهیافت تقریب­های خطی و غیرخطی، پایان نامه کارشناسی ارشد، مؤسسه ژئوفیزیک دانشگاه تهران.
Abubakar, A. and Habashy, T.M., 2005, A Green function formulation of the Extended Born approximation for three-dimensional electromagnetic modelling, Wave Motion 41(3): 211-227.
Anderson, W.L., 1984, Computation of Green’s tensor integrals for three-dimensional electromagnetic problems using fast Hankel transforms, Geophysics, 49(10), pp.1754-1759.
Aster, R.C., Borchers, B. and Thurber, C.H., 2018, Parameter estimation and inverse problems, Elsevier.
Backus, G., 1988, Comparing hard and soft prior bounds in geophysical inverse problems, Geophysical Journal, 94, 249-261 1988.
Black, N. and Zhdanov, M.S., 2010, Active Geophysical Monitoring of Hydrocarbon Reservoirs Using EM Methods, 40: 135-159.
Cai, H., Hu, X., Li, J., Endo, M., Xiong, B., 2017. Parallelized 3D CSEM mode ling using edge-based finite element with total field formulation and unstructured mesh. Computers & Geosciences 99, 125–134.
Chew, W.C., 1999, Waves and Fields in Inhomogeneous Media, IEEE Press: 632.
Constable, S. and Weiss, C.J., 2006, Mapping thin resistors and hydrocarbons with marine EM methods: Insights from 1D modeling. Geophysics, 71(2), pp. G43-G51.
Cox, C., 1981, On the electrical conductivity of the oceanic lithosphere", Phys Earth Planet, in 25(3), 196-201.
Dunham, M.W., Ansari, S.M.m and. Farquharson, C/G., 2018, Application of 3D marine controlled-source electromagnetic finite-element forward modeling to hydrocarbon exploration in the Flemish Pass Basin offshore Newfoundland, Canada, GEOPHYSICS 83: WB33-WB49.
Everett, M.E., and Meju, M.A., 2005, Near-surface controlled-source electromagnetic induction, In Hydrogeophysics (pp. 157-183). Springer, Dordrecht.
Habashy, T.M. Groom, R.W. and Spies, B.R., 1993, Beyond the Born and Rytov approximations: a nonlinear approach to electromagnetic scattering: Journal of Geophysical Research, 98, 1759–1775.
Hohmann, G. W., 1988, Electromagnetic methods in applied geophysics: Volume 1, Theory, Edited by Misac N. Nabighian: Society of Exploration Geophysicists, Tulsa, Oklahoma.
Hudson, J.A. and Herritage, J.R., 1981, The use of the Born approximation in seismic scattering problems, Geophys. J.R. Astron. Soc., 66, 221−240.
Hursan, G. and Zhdanov, M.S., 2002, “Contraction integral equation method in three‐dimensional electromagnetic modeling”, Radio Science, 37(6).
Jakobsen, M., 2012, T-matrix approach to seismic forward modelling in the acoustic approximation, Studia Geophysica Et Geodaetica 56(1): 1-20.
Key, K., 2012, Marine electromagnetic studies of seafloor resources and tectonics, Surveys in geophysics, 33(1), pp.135-167.
Lawless, J. F. and Wang, P. 1976, A simulation study of ridge and other regression estimators, Communications in Statistics, A 5: 307–323.
Lien, M., & Mannseth, T. 2008, Sensitivity study of marine CSEM data for reservoir production monitoring, Geophysics, 73(4), F151-F163.
Peng, R., Hu, X., Li, J., Liu, Y., 2020, Finite Element Simulation of 3-D Marine Controlled Source Electromagnetic Fields in Anisotropic Media with Unstructured Tetrahedral Grids. Pure Appl. Geophys.
Tikhonov, A.N. and Arsenin, V.I., 1977, Solutions of ill-posed problems, Vol. 14.
Torres-Verdin, C. and Habashy, T. M., 1995, Rapid 2.5-dimensional forward modeling and inversion via a new scattering approximation, Radio Science, 29 (4), 10.
Yao, Y. Liming, S. and Shangxu, W., 2005, Research on the seismic wavefield of karst cavern reservoirs near deep carbonate weathered crusts, Appl. Geophys., 2, 94−102.
Yoon, D. Zhdanov, M. M. Ma ttsson, J. Cai, H. and Gribenko, A. 2016, A hybrid finite-difference and in tegral-equation method for model-ing and inversion of marine controlled-source electromagnetic data, Geophysics, vol. 81, no. 5, pp. E323–E336.
Wannamaker, Ph. E & et al, 1984, “Electromagnetic modeling of three-dimensional bodies in layered earths using integral equations”, GEOPHYSICS. VOL. 49. NO. I, P. 60-74.
Zhdanov, M.S., 2009, Geophysical electromagnetic theory and methods, Vol. 43, Elsevier.
Zhdanov, M.S. Lee, S.K. and Yoshioka, K., 2006, Integral equation method for 3-D modeling of electromagnetic fields in complex structures with inhomogeneous background conductivity: Geophysics, 71, G33–G345.
Zhou, F., Tang, J., Ren, Z. et al. A hybrid finite-element and integral-equation method for forward modeling of 3D controlled-source electromagnetic induction. Appl. Geophys. 15, 536–544 (2018).
 
Volume 7, Issue 2
January 0
Pages 159-172

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