Enhancing Electromagnetic Field Over Resistive Offshore Hydrocarbon Using Synthetic Conduction Current Incurvature

Marine Controlled-Source Electromagnetic as an established alternative method for offshore hydrocarbon prediction is a successful technique to detect the electrically resistive anomalies in deep waters. However, in shallow water, its certainty of hydrocarbon delineation is arguable due to airwave presence when using a conventional Horizontal Electric Dipole (HED). In this paper, we propose a structural alteration in the HED source that uses conduction current method. The modification is in the form of a synthetic incurvation of the source to focus the down-going wave and disperse the airwave. We examined modified sources of different incurvature factors, a, using synthetic data generated by 1D numerical solution based on integral equation and simulation models based on Finite Element Method. The numerical calculation and simulation�s correlation coefficient that varies from 0.80 to 0.96 (depending on the incurvation factor) validate the agreement between the two methods. For a hydrocarbon target located at a depth of 1 km, we observed a contrast of 34 between with and without hydrocarbon models using modified source with curvature factor a = 0.4, whereas using the HED, the contrast was 22. For a 4 km deep target, this modified source showed 19 contrast, whereas the delineation using the HED was almost negligible. In addition, we processed a shallow water (150 m) analysis with a deep target (4 km) in which the proposed design produced a maximum contrast of 11 compared to the HED that featured only 4 delineation. These remarkable responses using the synthetic incurvation of HED can be a breakthrough for the offshore hydrocarbon exploration industry. © 2021, King Fahd University of Petroleum & Minerals.