In the last two decades, electromagnetic (EM) methods have been widely adapted for hydrocarbon exploration. Hydrocarbon saturated reservoir rock is typically electrically resistive relative to brine filled host rocks and or seal rocks. This work examines the applicability of electromagnetic methods consisting of passive magnetotelluric (MT) and active long-offset transient electromagnetic (LOTEM) to explore deep host hydrocarbon reservoirs. Synthetic models as derived from deep laterolog (LLD) data obtained at Bunga Field, Matindok Block, are applied in this work by changing the layer parameters, i.e. resistivity, thickness and depth of the hydrocarbon-bearing carbonate layers. A one-dimensional forward modeling scheme is employed to the methods and used to evaluate their responses due to the difference in layer parameters. This work concludes that the methods clearly detect high resistive layer associated with hydrocarbon reservoir. However, the major practical limitation on application of these EM methods is the reservoir depth. This reservoir depth was found to be far more significant than reservoir thickness or resistivity value.
Author : Budi S. Suryopranoto, Djedi S. Widarto, Hendra Grandis, Arief Wicaksono