Heavy oil (HO) is often produced with Enhanced Oil Recovery (EOR) methods such as steam or water flooding. In addition to flood front movements reservoir seal integrity has become an issue. Seal integrity is best addressed with microseismics and water flood front bets with electromagnetics. We address the fluid imaging problem using electromagnetics and after careful 3D feasibility and noise tests. We selected Controlled Source Electromagnetics (CSEM) in the time domain as the most sensitive method. From the 3D modeling we derived as key requirement that borehole and surface data needed to be integrated by measuring between surface to borehole and also calibrated using conventional logs.

Depending on the resistivity contrasts between the reservoir and the surrounding formation we need to measure electric AND magnetic fields as each of them have different sensitivity. The magnetic field senses more conductive strata, while the electric field will define fluid changes inside the HO reservoir. Furthermore, for shallow reservoir multi-frequency band sensors need to be deployed to get the optimum sensitivity.

Over the last decades we carried out 3D feasibilities for many oil fields and we are presently conducting the FIRST steam flood Pilot in an oil field in Asia. We also design custom data acquisition system for land, marine and borehole. Carrying out a Feasibility for each reservoir is key to control risk and cost. 3D modeling allows to integrate complex nature of the reservoir by constraining the model with existing seismic data. In all hydrocarbon cases it shows the need for full tensor CSEM, surface and borehole measurements to effectively determine the HO/steam flood front.

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