Reservoir quality prediction with CSEM

CSEM sensitivity to buried resistors is a function of the area, thickness, and resistivity of the resistive body. CSEM information in an exploration process will therefore generally imply changes to one or more of a prospect’s area, thickness, and resistivity expectation. Changes in the area and thickness lead to changes in the expected recoverable volume and risk assessment (Baltar and Barker, 2015). To date, any change in reservoir resistivity expectation has typically been used, at most, to impact the saturation expectation (Loseth et al., 2014). Such an approach overlooks material information regarding reservoir flow capacity, a property that directly influences the producibility, and therefore value, of a field. In this paper, we outline an interpretation framework within which this additional information-value may be realized. We first detail a suitable rock physics framework for relating the CSEM resistivity measurement to reservoir properties, then consider the information conveyed by the change in the reservoir resistivity expectation. We illustrate how this information can be interpreted with both synthetic and real-life examples, and consider its impact on the value of a prospect.