Borehole Calibration of PS-Waves for Fracture Characterization – Pinedale Field, Wyoming

Gaiser, James; Dok, Richard R. Van

doi:10.3997/2214-4609-pdb.17.a31

Cited by 7 publications

(3 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The correlation of this anisotropy pattern with sea-floor subsidence caused by the reservoir collapse after years of production suggests that shear waves are highly sensitive to local, deformation-induced stresses. Sensitivity of the polarization direction of the PS1-wave to local stresses over anticlines has also been observed at Emilio Field in the Adriatic Sea , and at Pinedale Field in Wyoming, USA (Gaiser and Van Dok, 2005). As illustrated by Figure 8, the PS1-wave at Emilio Field is polarized parallel to the crest of a doubly plunging anticline (thick black arrows), where anisotropy is generally higher.…”

Section: Mode-converted Ps-wavesmentioning

confidence: 66%

Seismic anisotropy in exploration and reservoir characterization: An overview

Gaiser²,

et al. 2010

View full text Add to dashboard Cite

Recent advances in parameter estimation and seismic processing have allowed incorporation of anisotropic models into a wide range of seismic methods. In particular, vertical and tilted transverse isotropy are currently treated as an integral part of velocity fields employed in prestack depth migration algorithms, especially those based on the wave equation. Here, we briefly review the state of the art in modeling, processing, and inversion of seismic data for anisotropic media. Topics include optimal parameterization, body-wave modeling methods, P-wave velocity analysis and imaging, processing in the τ -p domain, anisotropy estimation from vertical seismic profiling (VSP) surveys, moveout inversion of wide-azimuth data, amplitude-variation-with-offset (AVO) analysis, processing and applications of shear and mode-converted waves, and fracture characterization. When outlining future trends in anisotropy studies, we emphasize that continued progress in data-acquisition technology is likely to spur transition from transverse isotropy to lower anisotropic symmetries (e.g., orthorhombic). Further development of inversion and processing methods for such realistic anisotropic models should facilitate effective application of anisotropy parameters in lithology discrimination, fracture detection, and time-lapse seismology.

show abstract

Section: Mode-converted Ps-wavesmentioning

confidence: 66%

Seismic anisotropy in exploration and reservoir characterization: An overview

Gaiser²,

et al. 2010

View full text Add to dashboard Cite

show abstract

“…The reservoirs consist of naturally fractured gas-filled sandstone. The results of the shear-wave layer-stripping analysis, described by Gaiser and Van Dok (2005), suggested areas of increased fracturing in the overburden and the reservoir over the crest and limbs of the Pinedale anticline.…”

Section: Introductionmentioning

confidence: 99%

Reconstruction of the layer anisotropic elastic parameters and high‐resolution fracture characterization from P‐wave data: a case study using seismic inversion and Bayesian rock physics parameter estimation

Bachrach

Sengupta

Salama

et al. 2009

Geophysical Prospecting

View full text Add to dashboard Cite

A B S T R A C TWide-azimuth seismic data can be used to derive anisotropic parameters on the subsurface by observing variation in subsurface seismic response along different azimuths. Layer-based high-resolution estimates of components of the subsurface anisotropic elastic tensor can be reconstructed by using wide-azimuth P-wave data by combining the kinematic information derived from anisotropic velocity analysis with dynamic information obtained from amplitude versus angle and azimuth analysis of wide-azimuth seismic data. Interval P-impedance, S-impedance and anisotropic parameters associated with anisotropic fracture media are being reconstructed using linearized analysis assuming horizontal transverse anisotropy symmetry. In this paper it is shown how additional assumptions, such as the rock model, can be used to reduce the degrees of freedom in the estimation problem and recover all five anisotropic parameters. Because the use of a rock model is needed, the derived elastic parameters are consistent with the rock model and are used to infer fractured rock properties using stochastic rock physics inversion. The inversion is based on stochastic rock physics modelling and maximum a posteriori estimate of both porosity and crack density parameters associated with the observed elastic parameters derived from both velocity and amplitude versus angle and azimuth analysis. While the focus of this study is on the use of P-wave reflection data, we also show how additional information such as shear wave splitting and/or anisotropic well log data can reduce the assumptions needed to derive elastic parameter and rock properties.

show abstract

“…This arrangement leads to the effective horizontal transverse isotropy (HTI), its anisotropy coefficients can be estimated from seismic data and related back to the fractures. The papers presented at the workshop exploited HTI model and discussed various approaches to inferring the crack density, fracture orientation, and the type of fluid infill from such seismic signatures as normal-moveout (NMO) velocities 1 , amplitude-versus-offset (AVO) variations [2][3][4][5] , and shear-wave splitting coefficients 6 .…”

Section: Introductionmentioning

confidence: 99%

Seismic characterization of multiple fracture sets at Rulison Field, Colorado

Vasconcelos

Grechka

2007

GEOPHYSICS

View full text Add to dashboard Cite

Conventional fracture-characterization methods assume the presence of a single set of aligned, vertical cracks in the subsurface. We relax this assumption and demonstrate the feasibility of seismic characterization of multiple fracture sets. Our technique relies on recent numerical findings, indicating that multiple, differently oriented, possibly intersecting planar cracks embedded in an otherwise isotropic host rock result in a nearly orthorhombic (or orthotropic) effective medium. Here, the governing parameters of crack-induced orthotropy are estimated from 3D, wide-azimuth, multicomponent seismic reflection data acquired over the tight-gas Rulison Field in Colorado, USA.We translate strong azimuthal variations of the normal-moveout velocities into interval crack densities, fracture orientations, type of fluid infill, and velocities of the P-and S-waves in an unfractured rock. Our inversion procedure identifies a set of cracks aligned in approximately WNW-ESE direction in the western part of the study area and multiple, likely intersecting fractures in its eastern part. We validate both our underlying theoretical model and the obtained estimates by two independent measurements: (i) the estimated fluid-infill parameter indicates dry cracks as expected for the gas-producing sandstones at Rulison; and (ii) the obtained crack orientations are supported by measurements in a well. As a by-product of fracture characterization, we build an anisotropic velocity model of the Rulison reservoir that, we believe, is the first orthorhombic velocity field constructed from surface seismic data.

show abstract

Borehole Calibration of PS-Waves for Fracture Characterization – Pinedale Field, Wyoming

Cited by 7 publications

References 7 publications

Seismic anisotropy in exploration and reservoir characterization: An overview

Seismic anisotropy in exploration and reservoir characterization: An overview

Reconstruction of the layer anisotropic elastic parameters and high‐resolution fracture characterization from P‐wave data: a case study using seismic inversion and Bayesian rock physics parameter estimation

Seismic characterization of multiple fracture sets at Rulison Field, Colorado

Contact Info

Product

Resources

About