Spatial variation in azimuthal anisotropy due to sand-shale distribution: Stybarrow Field case study

Lisa J. Gavin; David Lumley

doi:10.1071/ASEG2013ab091

ISSN: 2202-0586
E-ISSN:

oa Spatial variation in azimuthal anisotropy due to sand-shale distribution: Stybarrow Field case study
Authors Lisa J. Gavin^a and David Lumley^b
View Affiliations Hide Affiliations

^a Centre for Petroleum Geoscience and CO2 SequestrationThe University of Western Australia, M004, 35 Stirling Highway, Crawley, , WA, , Australia, 6009, [email protected] ^b Centre for Petroleum Geoscience and CO2 SequestrationThe University of Western Australia, M004, 35 Stirling Highway, Crawley, , WA, , Australia, 6009, [email protected]
Publisher: Australian Society of Exploration Geophysicists
Source: ASEG Extended Abstracts, Volume 2013, Issue ASEG2013 - 23rd Geophysical Conference, Dec 2013, p. 1 - 4
DOI: https://doi.org/10.1071/ASEG2013ab091
- Published online: 01 Dec 2013

Abstract

Anomalous horizontal stress conditions within reservoir rock can result in azimuthally anisotropic elastic properties, the effects of which can be observed in borehole and 3D seismic data. The amount of stress- induced anisotropy can vary depending on sedimentary rock type and on subsurface stress conditions. There is currently no methodology we are aware of to quantify the relationship between azimuthal anisotropy and sand-shale content in unconsolidated sediments. We use data from the Stybarrow Field, located offshore NW Australia in the Carnarvon Sedimentary Basin, which is an area where strong anomalous horizontal stress conditions are present and have induced azimuthal anisotropy. We model azimuthally anisotropic gathers from logs and spatially correlate azimuthal AVO variations with sand-shale content. We derive a relationship that predicts the Thomsen parameter gamma as a function of the shale volume (for volume ratios greater than 0.3), and use this relationship to predict spatial variations in the azimuthal anisotropic AVO observed in the seismic data at Stybarrow. Implications from this work are that azimuthal anisotropy can be a strong function of sand- shale content, and that spatial variations in the sand-shale ratio can be estimated from azimuthal AVO.

Article metrics loading...

/content/journals/10.1071/ASEG2013ab091

2013-12-01

2026-01-25

From This Site

/content/journals/10.1071/ASEG2013ab091

dcterms_title,dcterms_subject,pub_keyword

-contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution

10

5

Full text loading...

References

Bishop, K., Osadcheck, A., and Stanley, M., 2010, Analysis methodology for azimuthal anisotropy: 72nd EAGE Conference and Exhibition, Expanded Abstracts, B048.
Contreras, P., Grechka, V. & Tsvankin, I., 1999, Moveout inversion of P-wave data for horizontal transverse isotropy: Geophysics, 64, 1219-1229.
Gavin, L., and Lumley, D., 2012, Seismic azimuthal AVO analysis at Stybarrow Field, NW Shelf, Australia: 83 rd Meeting, SEG, Las Vegas, Expanded Abstracts.
Gavin, L.J., Lumley, D., and Shragge, J., 2012, Seismic azimuthal anisotropy analysis for estimating reservoir properties at Stybarrow Field, NW Shelf, Australia:22nd International Conference and Exhibition: ASEG, Brisbane.
Hillis, R. R., and Reynolds, S.D., 2000, The Australian stress map: Journal of the Geological Society, 157, 915-921.
Hung, B., Zhang, F., Sun, J., Stanley, M., and Osadchuk, A., 2006, An automated 3D method for azimuthal anisotropy analysis in marine seismic data: 69th EAGE Conference and Exhibition, Expanded Abstracts, H035.
Pevzner, R., Gurevich, B., and Duncan, G., 2009, Estimation of azimuthal anisotropy from VSP data using multicomponent velocity analysis: 71st EAGE Conference and Exhibition, Expanded Abstracts, P192.
Rüger, A., 1998, Variation of P-wave reflectivity with offset and azimuth in anisotropic media: Geophysics, 63, 935-947.
Thomsen, 1986, Weak elastic anisotropy: Geophysics, 51, 1954-1966.
Thomsen, L., 1988, Reflection seismology over azimuthally anisotropic media: Geophysics, 53, 304-313.

/content/journals/10.1071/ASEG2013ab091

Article Type: Research Article

Keyword(s): azimuthal anisotropy; sand-shale ratio

Most Cited This Month Most Cited RSS feed

- Inversion of data from electrical imaging surveys in water-covered areas
  
  Authors M. H. Loke and J. W. Lane
- Inversion of Magnetic Data from Remanent and Induced Sources
  
  Authors Robert G. Elllis, Barrry de Wet and Ian N. Macleod
- A comparison of smooth and blocky inversion methods in 2-D electrical imaging surveys
  
  Authors M. H. Loke, Ian Acworth and Torleif Dahlin
- Designing matched bandpass and azimuthal filters for the separation of potential-field anomalies by source region and source type
  
  Authors Jeffrey D. Phillips
- Bad Colour Maps Hide Big Features and Create False Anomalies
  
  Authors Peter Kovesi
- Practical 3D EM inversion – the P223F software suite
  
  Authors Art Raiche, Fred Sugeng and Glenn Wilson
- Estimating Noise Levels in AEM Data
  
  Authors Andy Green and Richard Lane
- Target delineation using Full Tensor Gravity Gradiometry data
  
  Authors Colm A. Murphy and James Brewster
- Transdimensional Monte Carlo Inversion of AEM Data
  
  Authors Ross C Brodie and Malcolm Sambridge
- The geotech VTEM time domain helicopter em system
  
  Authors Ken Witherly, Richard Irvine and Edward Morrison
More Less

oa Spatial variation in azimuthal anisotropy due to sand-shale distribution: Stybarrow Field case study

Abstract

Most Read This Month

Most Cited This Month Most Cited RSS feed