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Elastic Inversion Using Partial Stack Seismic Data: Case
Histories in China
OutlineOutline
Introduction
Work Flow
Case Histories
Conclusions
Introduction
Background of Elastic Parameter Inversion
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Background of Elastic Parameter Inversion
Comparison of elastic impedance and acoustic impedance on recognizing of reservoir lithology
(According to Connolly.Patrick,1999)
Background of Elastic Parameter Inversion
Result of Acoustic Impedance Inversion
Result of Elastic Impedance Inversion
(According to Connolly.Patrick,1999)
Oil-bearing reservoir Unidentified
Oil-bearing reservoir identified clearly
OutlineOutline
Introduction
Work Flow
Case Histories
Conclusions
Seismic data processing
Petrophysical modeling
Elastic impedance generation
Wavelet estimation and horizon calibration
AVA Constrained Sparse Spike Inversion
Work Flow of Elastic Parameter Inversion
Seismic Data Processing Flow
INPUT COMMON-SHOT GATHERS
Amplitude Recovery
Filtering
Spiking Deconvolution
Bandpass Filter
CMP Sorting
Residual Statics
Velocity Analysis
Kirchhoff Pre-stack Time Migration
Common-angle Gather Extraction
Limited-angle Stacking
OUTPUT MIGRATED COMMON-ANGLE DATA
3-D Random Noise Attenuation
0-10 deg 10-20 deg
Full stack20-30 deg
Seismic Data Volume of Partial Angle Gather Stack
Shale volume Total porosity Temperature , pressure, fluid type & density
Vp&Vs modeling of brine-bearing reservoirs
Vp&Vs modeling of oil & gas-bearing reservoirs
Cross-plot analysis of elastic parameters of lithologies & fluids
Petrophysical model： Xu&White (DEM) & SCA
Petrophysical Modeling
Calculation of elastic parameters
Guide to identifying reservoirs & fluids
Petrophysical Modeling
A plot of petrophysical modeling of borehole logging data
Vsh Density M-PVp Sw M-PVsShear
modulus Lambda Poisson’s
ratio Vp/Vs S-imp P-imp Total porosity
Cross-plot Analysis of Elastic Parameters
shSw
Sand
Shale
Oil sand
Brine sand Brine sand
Oil sand
S-impedance
P-
imp
ed
an
ce
Lambda
Vp
/ V
s
P-
imp
ed
an
ce
Vp / Vs
S-impedanceP-impedanceVp / VsSwTotal-ProVsh
Wavelet & synthetic seismogram(0-10deg angle gathers stack)
Wavelet Estimation and Horizon Calibration
Various wavelets are extracted from near, middle and far offset angle gather stack seismic data using elastic impedance curves corresponding with angle series of seismic data.
Wavelet & synthetic seismogram(10-20deg angle gathers stack)
Wavelet & synthetic seismogram(20-30deg angle gathers stack)
Wavelet analysis of different angle gathers
0-10deg
10-20deg
20-30deg
Wavelet Estimation and Horizon Calibration
Interpolated wavelet & interpolation weights
Wavelet amplitude spectrum, phase spectrum, and time-frequency analysis
OutlineOutline
Introduction
Work Flow
Case Histories
Conclusions
Case Histories
0-10deg
10-20deg
20-30deg
Case 1. Changqing Oilfield
Coal bed
S-impedance
P-impedance
Case 1. Changqing Oilfield
Gas sandstone
Sandstone existence
Case 1. Changqing Oilfield
Lambda
Gas sandstone
Well BWell A
Gas sandstone
Vp/Vs
0-12deg 12-24deg
fullstack24-36deg
Case 2. Zhunger Oilfield
P-impedance of post-stack acoustic inversion
Case 2. Zhunger Oilfield
P-impedance of pre-stack elastic inversion
Poisson’s ratio
Case 2. Zhunger Oilfield
S-impedance
Vp/Vs
S-impedance
Case 2. Zhunger Oilfield
Case 2. Zhunger Oilfield
Red and yellow colors
show the favorable
distribution of
oil-bearing reservoirs
Favorable area :
40 Km2
Dry well
Oil well
Proposed well
OutlineOutline
Introduction
Work Flow
Case Histories
Conclusions Conclusions
Elastic inversion is more powerful than conventional post-stack acoustic inversion, which provides more petro-physical parameters used in identifying lithology and fluid distribution in a reservoir.
Our elastic inversion result fits very well with drilling results.
Elastic inversion obviously is a major direction in reservoir characterization.
Conclusions
Thank you for your attention!
