Reservoir Fluids Identification Using Vp/Vs Ratio?

Hamada, G.M.

doi:10.2516/ogst:2004046

Cited by 77 publications

(41 citation statements)

References 13 publications

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“…The V p / V s is also used as an indicator of the existence of gas phase in pore space [e.g. ]. The observed V p / V s values slightly increase from 1.43 to1.56 with an increase in effective stress from 2 to 55 MPa.…”

Section: Model Validation and Experimental Studiessupporting

confidence: 85%

Stress‐dependent elastic wave velocity of microfractured sandstone

Katsuki

Gutierrez

Almrabat

2013

Num Anal Meth Geomechanics

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SUMMARY A model for the stress‐dependent elastic wave velocity response of fractured rock mass is proposed based on experimental evidence of stress‐dependent fracture normal and shear stiffness. Previously proposed models and previous experimental studies on stress‐dependent fracture stiffness have been reviewed to provide a basis for the new model. Most of the existing stress‐dependent elastic wave velocity models are empirical, with model parameters that do not have clear physical meanings. To propose the new model, the rock mass is assumed to have randomly oriented microscopic fractures. In addition, the characteristic length of microfractures is assumed to be sufficiently short compared to the rock mass dimensions. The macroscopic stress‐dependent elastic wave velocity response is assumed to be attributed to the stress dependency of fracture stiffness. The stress‐dependent fracture normal stiffness is defined as a generalized power law function of effective normal stress, which is a modification of the Goodman's model. On the other hand, the stress dependency of fracture shear stiffness is modeled as a linear function of normal stress based on experimental data. Ultrasonic wave velocity responses of a dry core sample of Berea sandstone were tested at effective stresses ranging from 2 to 55 MPa. Visual observation of thin sections obtained from the Berea sandstone confirms that the assumptions made for microstructure of rock mass model are appropriate. It is shown that the model can describe the stress‐dependent ultrasonic wave velocity responses of dry Berea sandstone with a set of reasonable material parameter values. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

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Section: Model Validation and Experimental Studiessupporting

confidence: 85%

Stress‐dependent elastic wave velocity of microfractured sandstone

Katsuki

Gutierrez

Almrabat

2013

Num Anal Meth Geomechanics

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“…Indeed, the contribution of pore fluid pressure changes to earthquake triggering at different rupture scales is recognized worldwide [Hardebeck and Hauksson, 1999;Husen and Kissling, 2001;Vidale and Shearer, 2006] and has been already invoked for several Italian Apennine cases [e.g., Antonioli et al, 2005;Chiarabba et al, 2011;Malagnini et al, 2012;Improta et al, 2014]. Fluid movements can be tracked by analyzing V P /V S ratio space-time changes [e.g., Lucente et al, 2010;Hamada, 2004]. Fluid movements can be tracked by analyzing V P /V S ratio space-time changes [e.g., Lucente et al, 2010;Hamada, 2004].…”

Section: Introductionmentioning

confidence: 99%

“…Detection, mapping, and tracking of fluid migration can notably be achieved using 4-D seismic tomography and is used especially for purposes such as oil exploration and reservoir monitoring [Lumley, 2001], understanding tectonic environments [Chiarabba et al, 2009], and volcano monitoring for short-to middle-term eruption forecasting [Patanè et al, 2006]. Fluid movements can be tracked by analyzing V P /V S ratio space-time changes [e.g., Lucente et al, 2010;Hamada, 2004]. However, these observables are not able to single out the type of fluid mixing and the relative percentage of saturation [Dupuy et al, 2016], which are necessary to define a reliable picture of the host rock physical properties.…”

Section: Introductionmentioning

confidence: 99%

From velocity and attenuation tomography to rock physical modeling: Inferences on fluid‐driven earthquake processes at the Irpinia fault system in southern Italy

Amoroso

Russo

Landro

et al. 2017

Geophysical Research Letters

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We retrieve 3‐D attenuation images of the crustal volume embedding the fault system associated with the destructive Ms 6.9, 1980 Irpinia earthquake by tomographic inversion of t* measurements. A high QP anomaly is found to be correlated with the 1980 fault geometry, while the QS model shows regional‐scale variations related to the NE edge of the uplifted pre‐Tertiary limestone. An upscaling strategy is used to infer rock properties such as porosity, consolidation, type of fluid mixing, and relative saturation percentage at 8–10 km fault depth. We constrain the porosity and consolidation in the ranges 4–5% and 5–9, respectively, with the possible fluid mixes being both brine‐CO2 and CH4‐CO2. The consolidation parameter range indicates high pore pressures at the same depths. These results support the evidence for a fracture system, highly saturated in gases and a seismicity triggering mechanism at the fault zone, which is strongly controlled by fluid‐induced pore pressure changes.

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“…Different rock physics attributes like V P /V S , σ, μ * ρ, λ * ρ, K sat − μ, I P and I S are applied to determine the rock properties which are effectively discriminate pore fluids in the prospective reservoir intervals. V P /V S ratio is a good tool for fluid identification [38]. It is observed that P-wave velocity decreases and S-wave velocity increases with increase in hydrocarbon saturation, which makes V P /V S ratio more sensitive fluid indicator.…”

Section: Crossplot Analysis Of Rock Physics Attributes For Fluid's DImentioning

confidence: 97%

An Integrated Seismic Interpretation and Rock Physics Attribute Analysis for Pore Fluid Discrimination

et al. 2015

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Accurate prediction of subsurface structures, lithologies and pore fluids, is of great interest for petroleum prospecting and reservoir characterization. Seismic reflection data are widely used to mark subsurface structures and lithologies. However, only seismic data are not sufficient to mark fluid heterogeneities present into the pores. Therefore, the use of integrated approach is vital to map subsurface heterogeneities with more accuracy. Based on seismic interpretation, the limestone of Chorgali Formation present in Ratana area of Northern Potwar, Pakistan is interpreted as reservoir rock. Structural interpretation revealed that the study area lies in compressional regime and structures formed are thrust and popups. The reservoir properties such as lithology, porosity, permeability, depositional environments, shale volume, fluid saturation, net pay thickness are determined from petrophysical analysis which confirms that reservoir characteristics of Chorgali limestone are enough to permit hydrocarbon production. Fluid substitution modeling is used to estimate different rock physics attributes such as compressibility, Lame's parameters and their product with density, P to S-wave velocity ratio, impedances and Poisson's ratio are computed as a function of pore fluid type (oil, gas, brine etc.). Sensitivity analysis is performed to derive fluid indicator coefficient which indicates the most appropriate and sensitive rock physics attribute that can be crossplotted to discriminate the rock saturated with different pore fluids (gas/brine/oil).

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Reservoir Fluids Identification Using Vp/Vs Ratio?

Cited by 77 publications

References 13 publications

Stress‐dependent elastic wave velocity of microfractured sandstone

Stress‐dependent elastic wave velocity of microfractured sandstone

From velocity and attenuation tomography to rock physical modeling: Inferences on fluid‐driven earthquake processes at the Irpinia fault system in southern Italy

An Integrated Seismic Interpretation and Rock Physics Attribute Analysis for Pore Fluid Discrimination

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