Analysis of the manifestation of the subaqueous zone of hydrocarbon influence in the electromagnetic transient process

Abstract

Introduction: promising accumulations of mineral resources are concentrated on the vast shelf frame of continental platforms. Some of them are subaqueous hydrocarbon (HC) deposits. Therefore, geological exploration in water areas, including electrical exploration using the induced polarization (IP) method, is a promising area of research. In this regard, it is necessary to determine the observation methodology for solving geological exploration problems in water areas. To do this, it is necessary to propose a geoelectric model for the conditions of water areas containing anomalously polarized rocks changed under the influence of hydrocarbon migration and perform calculations of the electromagnetic (EM) signal for them on a multi-space electrical installation;

Methodology: based on a number of published works, a geoelectric model of the subaqueous zone of epigenetic changes above a hydrocarbon deposit has been proposed. These changes in the model manifest themselves in anomalous polarizability. The object of the study is the geoelectric model of the underwater zone of influence of hydrocarbons and the electromagnetic transition process above it. Numerical modeling of an unsteady EM field was performed for normal and anomalous models;

Results and discussion: normal and anomalous geoelectric models were proposed, an assessment of the anomalous effect was made depending on the size of the multi-space installation, the height of the installation above the bottom of the water area and the depth of the roof of the anomalous layer;

Conclusion: the anomalous effect depends not only on the manifestation of an anomalously polarized object, but on the type of manifestation of the induced polarization signal in the transient process.