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Uncertainty in Time-Lapse Saturation Signal Due to Uncertainty in (κframe/κ0) Ratio
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 81st EAGE Conference and Exhibition 2019, Jun 2019, Volume 2019, p.1 - 5
Abstract
The ratio of the rock frame bulk modulus to mineral bulk modulus κframe/κ0 is one of the key parameters in the Gassmann fluid substitution model. While much effort has been directed to the explanation of the rock frame elastic moduli, less attention has been paid to characterization of this ratio. This is partly because the variability of the mineral elastic moduli in sandstones is overlooked in the literature. In this article, the uncertainty of this ratio has been evaluated for four rock frame models in a deep turbidite reservoir with sand-shale mixture. It is shown while all these models could successfully model the wireline sonic log data, their predicted time-lapse responses could be different when inserted into the Gassmann modelling. This highlights the uncertainty in quantitative estimation of the timelapse saturation response and establishing the correct balance between the time-lapse pressure and saturation signals.