Affiliations: [a] College of Geo-Exploration Sciences and Technology, Jilin University, Changchun 130026, Jilin, China | [b] College of Earth Sciences, Guilin University, Guilin 541006, Guangxi, China
Correspondence:
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Corresponding author: Hanbo Chen, College of Geo-Exploration Sciences and Technology No. 938 Ximinzhu Street, Changchun130026, Jilin, China. Tel.: +86 15296003522; E-mail: [email protected].
Abstract: In recent years, the controlled-sources electromagnetic method has been widely applied for oil and metallic ore exploration. It is necessary to study the effects of the constituents and microstructure in pyrite-bearing hydrocarbon-bearing reservoir sandstones on 3D marine controlled source electromagnetic sounding, so as to improve the accuracy of the marine controlled sources electromagnetic (MCSEM) Method. In this paper, we present a new finite element algorithm for 3D MCSEM modeling, which is based on unstructured grids. In the modeling, we adopted the secondary formulation for the quasi-static variant of Maxwell’s equation, so that the source singularity could be avoided effectively. We first applied the four-phase incremental model to calculate the conductivity of the pyrite-bearing hydrocarbon. This is of use in studying the electrical conductivity of pyrite-bearing sandstones. The finite element equations were solved by means of the preconditioned IDR(s) method. We applied our algorithm to calculate the response of various key parameters of MCSEM (i.e. pyrite content, porosity, pyrite conductivity, grain aspect ratio and water saturation). The results of the modeling show the performance of the algorithm, and are expected to assist in future CSEM data interpretation when a pyrite-bearing sandstone reservoir is encountered.
