Integrating rock physics and flow simulation to reduce uncertainties in seismic reservoir monitoring .

摘要

Over the last decade, with the increasing need to interpret seismic attributes for hydrocarbon detection and reservoir management, it has become most critical to reliably and accurately quantify not only the effects of pore fluids, but also the associated uncertainties. Uncertainty in sub-resolution saturation scales introduce uncertainties in interpretation of seismic signatures in terms of fluid saturations. The goal of this thesis is to identify and quantify uncertainties in the seismic response of pore fluid properties and distributions, and to reduce these uncertainties by integrating traditional rock physics techniques with knowledge of reservoir fluid flow.; Flow simulators often do not correctly predict seismically significant details such as the saturation distribution within a simulator cell, or the relative amounts of free gas and dissolved gas. We identify the production scenarios where such uncertainties can significantly affect the seismic modeling and interpretation, and recommend strategies for dealing with such situations.; A coarse-scale (patchy) mix of fluids always has a higher compressional velocity than a fine-scale (uniform) mix. If we do not know the sub-seismic scales of fluid distribution, the question that arises is: When is the uniform model appropriate, and when should we use the patchy model? We use fine-scale flow simulations to constrain sub-seismic scales of saturation and identify critical reservoir parameters that impact the sub-resolution saturation scales. We present a reservoir monitoring case study in which downscaling of smooth saturation outputs from the flow simulator to a more realistic patchy distribution was required to provide a good quantitative match with the time-lapse seismic data, even though the fine details in the saturation distribution were below seismic resolution. This important result has the potential to significantly impact and enhance the applicability of seismic data in reservoir monitoring.; Interdisciplinary integration of seismic measurements and rock physics with multiphase fluid flow helps to reduce uncertainties in sub-resolution spatial fluid distributions, and as a result, reduces uncertainties in interpreting seismic attributes for eismic attributes for reservoir management.