Probabilistic analysis and comparison of stress-dependent rock physics models

Price, David C.; Angus, Doug; García, Alejandro García; Fisher, Q.J.

doi:10.1093/gji/ggx151

Cited by 7 publications

(4 citation statements)

References 60 publications

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“…In reality, this process is highly uncertain, especially in overburden rocks where stress-velocity core data is often not available (e.g. Price et al 2016). This complex modelling step is beyond the scope of this study.…”

Section: Discussionmentioning

confidence: 99%

“…mechanical subsurface changes and has proven to be a challenging task (e.g. Price et al 2016). However, for the purposes of this study we simplify this step by assuming each lithological layer in our model has a similar stress-velocity relationship which is known.…”

Section: T H E G E O M E C H a N I C A L M O D E Lmentioning

confidence: 99%

“…We set dv/dσ = 0.004 km s −1 MPa −1 which is a fair representation of the (effective) stress-velocity relationship considering typical core-measurements (e.g. Price et al 2016). Specifically, we calculate changes to individual overburden layer vertical traveltimes t v as a result of production induced changes in layer thickness H and seismic (i.e.…”

Section: T H E G E O M E C H a N I C A L M O D E Lmentioning

confidence: 99%

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A multimethod Global Sensitivity Analysis to aid the calibration of geomechanical models via time-lapse seismic data

Price

Angus

García

et al. 2017

Geophysical Journal International

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Time-lapse seismic attributes are used extensively in the history matching of production simulator models. However, although proven to contain information regarding production induced stress change, it is typically only loosely (i.e. qualitatively) used to calibrate geomechanical models. In this study we conduct a multimethod Global Sensitivity Analysis (GSA) to assess the feasibility and aid the quantitative calibration of geomechanical models via near-offset time-lapse seismic data. Specifically, the calibration of mechanical properties of the overburden. Via the GSA, we analyse the near-offset overburden seismic traveltimes from over 4000 perturbations of a Finite Element (FE) geomechanical model of a typical High Pressure High Temperature (HPHT) reservoir in the North Sea. We find that, out of an initially large set of material properties, the near-offset overburden traveltimes are primarily affected by Young's modulus and the effective stress (i.e. Biot) coefficient. The unexpected significance of the Biot coefficient highlights the importance of modelling fluid flow and pore pressure outside of the reservoir. The FE model is complex and highly nonlinear. Multiple combinations of model parameters can yield equally possible model realizations. Consequently, numerical calibration via a large number of random model perturbations is unfeasible. However, the significant differences in traveltime results suggest that more sophisticated calibration methods could potentially be feasible for finding numerous suitable solutions. The results of the time-varying GSA demonstrate how acquiring multiple vintages of time-lapse seismic data can be advantageous. However, they also suggest that significant overburden near-offset seismic time-shifts, useful for model calibration, may take up to 3 yrs after the start of production to manifest. Due to the nonlinearity of the model behaviour, similar uncertainty in the reservoir mechanical properties appears to influence overburden traveltime to a much greater extent. Therefore, reservoir properties must be known to a suitable degree of accuracy before the calibration of the overburden can be considered.

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Section: Discussionmentioning

confidence: 99%

Section: T H E G E O M E C H a N I C A L M O D E Lmentioning

confidence: 99%

Section: T H E G E O M E C H a N I C A L M O D E Lmentioning

confidence: 99%

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A multimethod Global Sensitivity Analysis to aid the calibration of geomechanical models via time-lapse seismic data

Price

Angus

García

et al. 2017

Geophysical Journal International

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“…In a forward modeling workflow, hydromechanical modeling (either analytical or numerical) can be performed to estimate changes in stress due to pore pressure changes 15,17 . A stress sensitive rock physics relationship, either theoretical or empirical based, can then be used to convert stress changes to velocity changes 9,10,15,18 . The forward modeling studies performed for CO 2 storage have been typically focused on the impact of pressure and saturation on elastic wave velocity changes.…”

Section: Introductionmentioning

confidence: 99%

Quantifying the impact of effective stress on changes in elastic wave velocities due to CO₂ injection into a depleted carbonate reef

2021

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The interpretation of time‐lapse seismic monitoring of CO2 sequestration has typically focused on mapping the saturation and pressure changes. However, elastic wave velocity and associated seismic attribute variation also depend on the poroelastic response to CO2 injection. In this study, we investigated the impact of effective stress changes on elastic wave velocity responses during CO2 storage within a carbonate reef of the Michigan basin. The geomechanical multiphase flow modeling combined with the experimental measurements were used to investigate the impact of effective stress on changes in velocities. We measured the ultrasonic compressional (Vp) and shear (Vs) wave velocities in cores acquired from the carbonate formations under different stress‐pressure scenarios. Experimental scenarios were applied by changing the effective stress and pore pressure conditions simulating injection into the depleted reservoir. Experimental results show that incorporating stress changes of injection avoids overestimation of changes in velocities due to considering only pore pressure effects. Coupled multiphase flow – geomechanical simulations were performed to assess stress and saturation change during CO2 injection. We discussed expected changes in elastic wave velocities using combined simulation results with experimental ones. The simulation results show that both effective stress and saturation changes contribute to changes in velocities in the main reservoir. Effective stress is the dominant parameter that contributes to changes in velocities in the upper formations. Results of this work show that quantifying the poroelastic effect of stress on elastic wave velocities changes can lead to a better interpretation of changes in seismic attributes during CO2 injection. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd.

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A review of mechanical properties and constitutive theory of rock mass anisotropy

et al. 2020

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Probabilistic analysis and comparison of stress-dependent rock physics models

Abstract: This is a repository copy of Probabilistic analysis and comparison of stress-dependent rock physics models.

Cited by 7 publications

References 60 publications

A multimethod Global Sensitivity Analysis to aid the calibration of geomechanical models via time-lapse seismic data

A multimethod Global Sensitivity Analysis to aid the calibration of geomechanical models via time-lapse seismic data

Quantifying the impact of effective stress on changes in elastic wave velocities due to CO₂ injection into a depleted carbonate reef

A review of mechanical properties and constitutive theory of rock mass anisotropy

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Probabilistic analysis and comparison of stress-dependent rock physics models

Abstract: This is a repository copy of Probabilistic analysis and comparison of stress-dependent rock physics models.

Cited by 7 publications

References 60 publications

A multimethod Global Sensitivity Analysis to aid the calibration of geomechanical models via time-lapse seismic data

A multimethod Global Sensitivity Analysis to aid the calibration of geomechanical models via time-lapse seismic data

Quantifying the impact of effective stress on changes in elastic wave velocities due to CO2 injection into a depleted carbonate reef

A review of mechanical properties and constitutive theory of rock mass anisotropy

Contact Info

Product

Resources

About

Quantifying the impact of effective stress on changes in elastic wave velocities due to CO₂ injection into a depleted carbonate reef