Reservoir Monitoring by Broadband Q Factor Imaging

Abstract

Summary In a pioneering paper of Nur (1989) that boosted the time-lapse seismic research, two rock parameters are spotted to detect fluid saturation changes and monitor hydrocarbon reservoirs by seismic waves: anelastic absorption and propagation velocity. The second one became a hot research topic in the following decades. In this paper, we explore the other way suggested by Nur, i.e., anelastic absorption, as a tool for time-lapse reservoir monitoring. The diagnostic value of anelastic absorption for estimating fluid saturation is the higher, the wider is the frequency range of the seismic waves. Ideally, this range should start from the lowest frequencies of seismic surveys, i.e., a few Hz, and ideally reach the frequencies available in lab measurements of rock samples. Some advance has been achieved by Vesnaver et al. (2016), who introduced a new method for a broadband estimation of the Q factor and anelastic absorption. Its resolution is comparable to standard imaging for reflectivity and amplitude anomalies. In this paper, we test this method and validate the use of anelastic absorption for detecting time-lapse signals