Estimating indicators of oil-bearing fractured reservoirs from frequency components of azimuthal seismic data
- Huaizhen Chen (Department of Geoscience, University of Calgary) | Kristopher Innanen (Department of Geoscience, University of Calgary)
- Document ID
- Society of Exploration Geophysicists
- SEG International Exposition and Annual Meeting, 15-20 September, San Antonio, Texas, USA
- Publication Date
- Document Type
- Conference Paper
- 2019. Society of Exploration Geophysicists
- Anisotropy, Inversion, Fractures, Fluid flow in porous media, Wide azimuth (WAZ)
- 2 in the last 30 days
- 2 since 2007
- Show more detail
Based on a model of attenuative cracked rock, we derive a simplified and frequency-dependent stiffness matrix, and we present a new indicator of oil-bearing fractured reservoirs, which is related to pressure relaxation in cracked rocks and influenced by fluids. We set up a linearized P-wave to Pwave reflection coefficient as an azimuthally- and frequency dependent function of dry rock elastic properties, dry fracture weaknesses, and the new indicator. By varying this reflection coefficient with azimuthal angle, we derive a further expression referred to as the quasi-difference in elastic impedance, or QdEI, which is primarily affected by the dry fracture weaknesses and the new indicator. An inversion approach can be set up based on the QdEI which through differences in seismic amplitudes with frequency produces estimates of these weaknesses and the indicator. In synthetic inversion tests, we conclude the approach produces interpretable parameter estimates in the presence of data with a moderate signal-to-noise ratios (SNR). Testing on a real data set reveals that the dry fracture weakness estimates are reliable fracture predictors, and we conclude further that the estimated indicator provides an important discrimination tool for fluids in cracks.
Presentation Date: Monday, September 16, 2019
Session Start Time: 1:50 PM
Presentation Time: 3:30 PM
Presentation Type: Oral
|File Size||5 MB||Number of Pages||5|
Bakulin,A.,V.Grechka, andI.Tsvankin,2000,Estimation of fracture parameters from reflection seismic data — Part 1: HTI model due to a single fracture set:Geophysics,65,1788–1802,10.1190/1.1444863.
Carcione,J. M.,2000,A model for seismic velocity and attenuation in petroleum source rocks:Geophysics,65,1080–1092,10.1190/1.1444801.
Chen,H.,Y.Ji, andK. A.Innanen,2018,Estimation of modified fluid factor and dry fracture weaknesses using azimuthal elastic impedance:Geophysics,83,no.1,WA73–WA88,10.1190/geo2017-0075.1.
Hudson,J.,E.Liu, andS.Crampin,1996,The mechanical properties of materials with interconnected cracks and pores:Geophysical Journal International,124,105–112,10.1111/j.1365-246x.1996.tb06355.x.
Moradi,S., andK. A.Innanen,2016,Viscoelastic amplitude variation with offset equations with account taken of jumps in attenuation angle:Geophysics,81,no.3,N17–N29,10.1190/geo2015-0366.1.
Russell,B. H.,K.Hedlin,F. J.Hilterman, andL. R.Lines,2003,Fluid-property discrimination with AVO: A Biot-Gassmann perspective:Geophysics,68,29–39,10.1190/1.1543192.
Schoenberg,M., andC. M.Sayers,1995,Seismic anisotropy of fractured rock:Geophysics,60,204–211,10.1190/1.1443748.