Delineation of steam flood using seismic attenuation

Abstract

The possible use of attenuation measurements for time-lapse seismic monitoring of an EOR steam flood project in Saskatchewan, Canada is investigated. A VSP survey was used to calculate Q. These values were input to a synthetic seismogram attenuation modeling program that showed there should be an observable increase in attenuation after steam injection. Two seismic lines shot at the same location nine years apart were analyzed to see if attenuation anomalies were apparent. The results indicate a strong anomaly on the recent seismic line that is consistent with the location of steam injection. A weaker anomaly on the older line is consistent with the amount of steam injected at that time. Theoretical and laboratory analyses of compressional velocity as a function of changes in temperature, pressure, fluid type and fluid phase suggest there should be a measurable effect on compressional wave amplitude, isochron, and frequency response.

Mobility Effect on Poroelastic Seismic Signatures in Partially Saturated Rocks With Applications in Time‐Lapse Monitoring of a Heavy Oil Reservoir

“…In addition, during the thermal production process, the fluid pressure diffusion between methane and water might also lead to seismic attenuation (Dilay & Eastwood, 1995). The high seismic attenuation caused by thermal recovery in heavy oil sand has also been reported by Dilay and Eastwood (1995) and Hedlin et al (2001). In this section, we will use a time-lapse seismic data set in a SAGD heavy oil producing reservoir to explore the influences of mobility coupled with intrinsic attenuation on the seismic reflectivity signatures.…”

Seismic Determination of Reservoir Heterogeneity: Application to the Characterization of Heavy Oil Reservoirs

“…The effect could be caused by steam which often increases amplitudes by increasing impedance contrasts (Tague et al, 1999). Steam can also reduce instantaneous frequencies by attenuation (Hedlin et al, 2001). Lower frequencies may increase similarity because shifts in phase or time have a lesser effect on the wavelet.…”

Monitoring viscosity changes from time‐lapse seismic attenuation: case study from a heavy oil reservoir

“…It separates the effect of attenuation from geometric spreading and is first presented for laboratory measurements of rocks by Toksöz et al . () and adjusted for VSP and surface seismic in many studies (e.g., Hauge ; Badri and Mooney, Feustel and Young ; Chen and Sidney ; Dasgupta and Clark ; Sun and Castagna ; Hedlin Mewhort and Margrave ; Mateeva ; Wang ; Carter ; Vasconcelos and Jenner ; Matsushima ; Rickett ; Lecerf, Rogers, and Lefeuvre ; Reine, Clark, and van Der Baan ; Clark et al . ; Blanchard et al ., ; Reine et al .…”

“…The spectral ratio method is a common technique to estimate the attenuation (Q -factor) of the medium. It separates the effect of attenuation from geometric spreading and is first presented for laboratory measurements of rocks by Toksöz et al (1979) and adjusted for VSP and surface seismic in many studies (e.g., Hauge 1981;Badri andMooney, 1987 Feustel andYoung 1994;Chen and Sidney 1997;Dasgupta and Clark 1998;Sun and Castagna 2000;Hedlin Mewhort and Margrave 2001;Mateeva 2003;Wang 2003;Carter 2003;Vasconcelos and Jenner 2005;Matsushima 2006;Rickett 2006;Lecerf, Rogers, and Lefeuvre 2006;Reine, Clark, and van Der Baan 2009;Clark et al 2009;Blanchard et al, 2009;Reine et al 2012a,b). Note that, for surface seismic data, near surface effects make the measurements of attenuation even more difficult and less reliable.…”