Publications

Multi-Transient EM (MTEM) is a time-domain galvanic EM technology, implemented on land, in transition zones and marine environments, making it ideal for mapping subsurface resistors across all terrains. Further, it is high resolution with fieldoptimized technology making it an ideal complement to seismic methods.Direct hydrocarbon detection and production monitoring by means of seismic is possible provided the reservoir porosity is sufficiently high and the hydrocarbon fluid is light, i.e., gas or high API gravity oils with a high gas oil ratio (GOR). The limited number of fields suitable for seismic monitoring means there is a need for alternative solutions for situations where seismic fails, and MTEM is such a solution. EM has the unique ability to extract subsurface resistivity images from surface measurements, thus providing invaluable exploration and production information facilitating both direct hydrocarbon detection and time-lapse information throughout the life of the field.All aspects of MTEM data acquisition have been optimized to achieve a sufficiently dense surface sampling in relation to target depth, and to achieve the necessary S/N at target levela in the shortest possible time given a particular source strength. The unique feature that makes this possible is that the transmitted signal is measured simultaneous with the receiver signal allowing deconvolution to recover the earths impulse response. The optimized imaging makes MTEM the perfect complement to seismic solutions and can sometimes replace seismic imaging with direct hydrocarbon imaging for fluid characterization and time-lapse in situations where seismic fails. The suite of MTEM solutions introduced here include field delineation, de-risking low saturation gas, time-lapse monitoring of oil and gas production, water injection, CO2 sequestration and monitoring of steam injection production of heavy oils.