Empirical relationships among seismic velocity, effective pressure, porosity, and clay content in sandstone

Eberhart‐Phillips, D.; Han, D-H.; Zoback, M. D.

doi:10.1190/1.1442580

Cited by 460 publications

(240 citation statements)

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“…Step 3 It is the integration step where results from basin modeling study (i.e., distribution of mechanical properties of reservoir rocks over geological time) are correlated with each cell of geocellular model using empirical relationships (Eberhert-Phillips et al 1989;Ingram and Urai 1999;Horsrud 2001;Yarus and Carruthers 2014). Use of these empirical relationships provided a practical solution in discretizing geomechanical properties in the current study area.…”

Section: Integrated Modeling Approachmentioning

confidence: 99%

“…Once the effective stress distribution model is generated for the entire reservoir geocellular grid, rock mechanical properties such as V p , V s , UCS, BRI, OCR, Young's modulus, Poison's ratio, and bulk modulus are calculated at each cell locations of geocellular grid using empirical formula as provided below (Eberhert-Phillips et al 1989;Ingram and Urai 1999;Horsrud 2001;Yarus and Carruthers 2014): …”

Section: Model Integrationmentioning

confidence: 99%

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An integrated approach to discretized 3D modeling of geomechanical properties for unconventional mature field appraisal in the western Canadian sedimentary basin

Saikia

Ikuku

Sarkar

2017

J Petrol Explor Prod Technol

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In mature field appraisal and development, discretized geomechanical property models play a vital role in providing information on in situ stress regime as a guide for placement of directional wells. Laboratory methods of measuring these properties, in most cases, take only small samples from consolidated rocks. These isolated samples may not be representative of the entire elastic regime existing in the reservoir owing to sample size. In general, geomechanical studies are performed on a well-by-well basis and then these measurements are used as calibration points to convert 3D seismic data (if available) to geomechanical models. However, elastic properties measured this way are restricted to the well location and interpolation across the reservoir may not be always appropriate. To overcome these challenges, this paper describes an integrated approach for deriving 3D geomechanical models of the reservoir by combining results of 3D geocellular models and basin models. The basin model reconstructs the geologic history (i.e., burial history) of the reservoir by back-stripping it to the original depositional thickness. Through this reconstruction, the mechanical compaction, pore pressures, effective stress, and porosity versus depth relationships are established. Next, these mechanical properties are discretized into 3D geocellular grid using empirical formulas via lithofacies model even if no 3D seismic data are available for the reservoir. The discretization of elastic properties into 3D grids results in a better understanding of the prevailing stress regimes and helping in design of hydraulic fracturing operations with minimal risks and costs. This approach provides an innovative way of determining effective horizontal stress for the entire reservoir through 3D distribution of elastic properties.

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Section: Integrated Modeling Approachmentioning

confidence: 99%

Section: Model Integrationmentioning

confidence: 99%

An integrated approach to discretized 3D modeling of geomechanical properties for unconventional mature field appraisal in the western Canadian sedimentary basin

Saikia

Ikuku

Sarkar

2017

J Petrol Explor Prod Technol

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“…The velocity a increases exponentially as the pressure increases from the ambient pressure up to 100 MPa and continues to increase linearly up to 400 MPa. Exponential behavior of the velocity dependence on stress is addressed by many authors (e.g., Eberhart-Phillips et al, 1989;Freund, 1992;Jones, 1995;Khaksar et al, 1999;Shapiro, 2003). We can use the formalism of Shapiro (2003) to interpret this in terms of the compliant and stiff porosities,…”

Section: Wa96mentioning

confidence: 99%

Estimation of stress-dependent anisotropy from P-wave measurements on a spherical sample

et al. 2011

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Our aim is to understand the stress-dependent seismic anisotropy of the overburden shale in an oil field in the North West Shelf of Western Australia. We analyze data from measurements of ultrasonic P-wave velocities in 132 directions for confining pressures of 0.1-400 MPa on a spherical shale sample. First, we find the orientation of the symmetry axis, assuming that the sample is transversely isotropic, and then transform the ray velocities to the symmetry axis coordinates. We use two parameterizations of the phase velocity; one, in terms of the Thomsen anisotropy parameters a, b, e, d as the main approach, and the other in terms of a, b, g, d. We invert the ray velocities to estimate the anisotropy parameters a, e, d, and g using a very fast simulated reannealing algorithm. Both approaches result in the same estimation for the anisotropy parameters but with different uncertainties. The main approach is robust but produces higher uncertainties, in particular for g, whereas the alternative approach is unstable but gives lower uncertainties. These approaches are used to find the anisotropy parameters for the different confining pressures. The dependency of P-wave velocity, a, on pressure has exponential and linear components, which can be contributed to the compliant and stiff porosities. The exponential dependence at lower pressures up to 100 MPa corresponds to the closure of compliant pores and microcracks, whereas the linear dependence at higher pressures corresponds to contraction of the stiff pores. The anisotropy parameters e and d are quite large at lower pressures but decrease exponentially with pressure. For lower pressures up to 10 MPa, d always is larger than e; this trend is reversed for higher pressures. Despite the hydrostatic pressure, the symmetry axis orientation changes noticeably, in particular at lower pressures.

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“…The pore pressure dependence of the velocity of dry rocks is just approximated, as the measuring of this effect in the laboratory failed. It is described by the Eberhard-Phillips equation ( Zimmermann et al (1986); Eberhard-Phillips et al (1989);Shapiro (2003) )…”

Section: Saturated Rock Propertiesmentioning

confidence: 99%

Seismic Monitoring in the Framework of the Pilot Project CLEAN

Houpt¹

2010

72nd EAGE Conference and Exhibition Incorporating SPE EUROPEC 2010

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Empirical relationships among seismic velocity, effective pressure, porosity, and clay content in sandstone

Cited by 460 publications

References 0 publications

An integrated approach to discretized 3D modeling of geomechanical properties for unconventional mature field appraisal in the western Canadian sedimentary basin

An integrated approach to discretized 3D modeling of geomechanical properties for unconventional mature field appraisal in the western Canadian sedimentary basin

Estimation of stress-dependent anisotropy from P-wave measurements on a spherical sample

Seismic Monitoring in the Framework of the Pilot Project CLEAN

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