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The
Revealed with Full Azimuth 3D Multi-
Component Seismic Data.
By
Tony Rebec, Jim Gaiser, Alvaro Chaveste and Richard Vern,
Geokinetics, Houston.
- Introduction to the Marcellus Shale/data
- Geophysical Strategy
- Vertical Calibration & Resolution
- Spatial Resolution & Geometric Attributes
- Anisotropic/Rock Property Attributes
- Conclusions
The
Revealed with Full Azimuth 3D Multi-Component
Seismic Data.
United States Shale Gas Plays
500Tcf
Generalized Geologic Cross-Section of
Catskill Delta Magna Facies
+ Ordovician Utica Shale
Marcellus Shale – Depth & Isopach Maps
Depth Isopach
Bradford-Mehoopany 3D Pennsylvania
N
Net Feet of Organic Rich Shale
in the Marcellus Formation, Pennsylvania
Bradford County
Time Slice from Bradford 3D
Phase I & Mehoopany
Seismic Survey
3D/3C
Anisotropy
study 3D
Elevations
from
Acquisition
Zeroing in on the Marcellus Shale Play in Pennsylvania with High Fidelity 3D Full
Azimuth Surface Seismic Data Including Simultaneous Multi-Component 3D data for
Calibration and Identification of Fracture Sweet Spots. (Data not vertically corrected
for velocity differentials)
P-Wave Production P-Wave Component Shear-Wave Shear-Wave
Fast Component Slow Component
AJR
3D Data Sets
Geophysical Strategy
Maximize information obtained from seismic
(appropriate Acquisition/Processing) and
optimize its resolution:
1. Structural and stratigraphic framework
Trace and geometric attributes
2. Fracture characterization
Anisotropic attributes
3. Matrix (reservoir and rock) properties
Inversion attributes
Vertical Calibration/Resolution
Inline & Crossline
Tully
Marcellus
Syracuse Salt
Onondaga
Cut-a-way Seismic Cube
4388’
4496’
6076’
6228’
6249’
6382’
152’
133’
CHERRY VALLEY
28’
Marcellus Shale Vertical Resolution Sonic
Vertical Resolution
Seismic
Thin-Bed Reflectivity re Tanner
*
*
Spatial Resolution/Geometric Attributes
Onondaga
Amp
Base Marcellus Shale - twt
Top Marcellus Shale – seismic amplitude
J1 & J2 Fracture Sets in Marcellus
J1
J2
J1 J1
J2 J2
J1 & J2 Fracture Sets in Marcellus
Natural gas chimneys in black shale
showing cross fold J2 joints
Geology Seismic
Energy Ratio
Unbiased accurate faulting
time slice
Landmark GeoProbe
Co-rendered
seismic & semblance
Positive Curvature
Bradford & Mehoopany 3D
Seismic Attributes
Unbiased accurate structural deformation – positive flexures (highs)
Positive Curvature – time slice
Positive Curvature
time slice
High fidelity
Normal
Unbiased accurate structural deformation – negative flexures (lows)
time slice
Negative Curvature – time slice
1120 ms - Marcellus
Negative Curvature
time slice
High spatial fidelity
normal
Horizon TWT Horizon Textural Rendering Co-rendered
Textural Rendering
Anisotropic Attributes
Reservoir and Rock Properties
Vp, Vs, ρ
Amplitude
P-impedance
S-impedance
Poisson’s ratio
Young’s Modulus
LambdaRho
MuRho
Anisotropy
Lithology
Composition
Porosity
Fluid content
TOC content
Brittleness
Fractures
Pore pressure
Stress
etc.
Anisotropic/Rock Property Attributes
Anisotropy
1. Elliptical Inversion using P-wave Interval Velocities
2. Time differentials from Shear waves (3 comp)
Rock Properties
1. Lambda*Rho Mu *Rho
Density and Orientation of Micro-fractures
Physical Basis
Velocities dependence on fractures’ direction. <-
Cra
ck
Orien
tatio
n
Velocity Ellipse
A = Semi-major axis
B = Semi-minor axis
= Azimuth
A
B
N
<-C
rack
Orien
tatio
n
Velocity Ellipse
A = Semi-major axis
B = Semi-minor axis
= Azimuth
A
B
N
Difference between fast and slow velocities (anisotropy) is a measure of
fracture density
- Azimuth
VMAX
VMIN
(VMAX-VMIN)/VMAX
e - Error
Elliptical Inversion (EI) to estimate anisotropy
Time Slice: 680 ms
pstm stk Interval Velocities
All Azimuths
Hand-Picked
Interval Velocities
Azimuth 1
AutoVels
Interval Velocities
Azimuth 2
AutoVels
Interval Velocities
Azimuth 3
AutoVels
Interval Velocities
Azimuth 4
AutoVels
Automatic Velocity Picking
<-C
rack
Orien
tatio
n
Velocity Ellipse
A = Semi-major axis
B = Semi-minor axis
= Azimuth
A
B
N
<-C
rack
Orien
tatio
n
Velocity Ellipse
A = Semi-major axis
B = Semi-minor axis
= Azimuth
A
B
N
<-C
rack
Orien
tatio
n
Velocity Ellipse
A = Semi-major axis
B = Semi-minor axis
= Azimuth
A
B
N
<-C
rack
Orien
tatio
n
Velocity Ellipse
A = Semi-major axis
B = Semi-minor axis
= Azimuth
A
B
N
<-C
rack
Orien
tatio
n
Velocity Ellipse
A = Semi-major axis
B = Semi-minor axis
= Azimuth
A
B
N
<-C
rack
Orien
tatio
n
Velocity Ellipse
A = Semi-major axis
B = Semi-minor axis
= Azimuth
A
B
N
<-C
rack
Orien
tatio
n
Velocity Ellipse
A = Semi-major axis
B = Semi-minor axis
= Azimuth
A
B
N
<-C
rack
Orien
tatio
n
Velocity Ellipse
A = Semi-major axis
B = Semi-minor axis
= Azimuth
A
B
N
Low High
Better resolution velocity field
Velocity field for azimuthal NMO correction
Elliptical Inversion
Inline
Azimuth co-rendered with Stack
Anisotropy Azimuth (degrees)
Marcellus Marcellus
Elliptical Inversion Anisotropy Comparison
Sectored
From Interval Velocities
Un-sectored
From RMS Velocities
Stack
Elliptical Inversion Azimuth and Anisotropy
Top Marcellus + 40 msec
Anisotropy Azimuth (deg)
<-C
rack
Orien
tatio
n
Velocity Ellipse
A = Semi-major axis
B = Semi-minor axis
= Azimuth
A
B
N
<-C
rack
Orien
tatio
n
Velocity Ellipse
A = Semi-major axis
B = Semi-minor axis
= Azimuth
A
B
N
Elliptical Attributes
Un-sectored Elliptical Inversion
Elliptical Inversion Azimuth and Anisotropy
Top Marcellus + 40 msec
Anisotropy Azimuth (deg)
<-C
rack
Orien
tatio
n
Velocity Ellipse
A = Semi-major axis
B = Semi-minor axis
= Azimuth
A
B
N
<-C
rack
Orien
tatio
n
Velocity Ellipse
A = Semi-major axis
B = Semi-minor axis
= Azimuth
A
B
N
Elliptical Attributes
Sectored Elliptical Inversion
Co-rendered Azimuth/Anisotropy - Positive Curvature
Azimuth
Anisotropy
J1 – “Maintains ENE orientation regardless
of location relative to the oroclinal bends”
J2 - “In the Valley and Ridge, J2 is found
normal to fold axes…”
Engelder, T. “Structural geology of the Marcellus and
other Devonian gas shales”
Anisotropic/Rock Property Attributes
Anisotropy
1. Elliptical Inversion using P-wave Interval Velocities
2. Time differentials from Shear waves (3 comp)
Rock Properties
1. Lambda*Rho Mu *Rho
PS2 to PS1 Registration
PS2 to PS1 Registration
Time to Top Salt
PS2 to PS1 Registration
Cumulative Time Differences PS1 Stack
PS2 to PS1 Registration
Absolute
Interval Anisotropy PS1 Stack
Fracture Characterization
• Geometric attributes for subtle
changes in regional trends – fold,
fault, fracture
• Anisotropic attributes through
elliptical inversion
Fracture location, azimuth
and intensity
Multiple, complementary
methods
Converted wave solutions
• Methods to constrain and
calibrate. Azimuth (deg) Anisotropy (%)
Co-rendered Positive Curvature
with Anisotropy
Anisotropic/Rock Property Attributes
Anisotropy
1. Elliptical Inversion using P-wave Interval Velocities
2. Time differentials from Shear waves (3 comp)
Rock Properties
1. Lambda*Rho Mu *Rho
Reservoir and Rock Properties
Vp, Vs, ρ
Amplitude
P-impedance
S-impedance
Poisson’s ratio
Young’s Modulus
LambdaRho
MuRho
Anisotropy
Lithology
Composition
Porosity
Fluid content
TOC content
Brittleness
Fractures
Pore pressure
Stress
etc.
Reservoir and Rock Properties
P-wave Impedance S-wave Impedance
Lambda*Rho (lr) Mu*Rho (mr)
Density
Lambda*Rho - Mu*Rho
Cross-plot
4400 to 8000 ft
lr
mr
Lambda*Rho (lr)
Reservoir and Rock Properties
Log Crossplot
Seismic Crossplot
Cross-plot from Seismic
Density Density
Lambda*Rho (lr) Mu*Rho (mr)
Low density ~ high TOC
Conclusions
Using Seismic Effectively in the Marcellus Unconventional
Play
• Begins with acquiring and processing high resolution image
• Provides structural and stratigraphic framework – Well placement, hazard avoidance and geosteering
– Reservoir architecture and delineation
– Geometric attributes may predict stress/ fracture zones
• Fracture characterization – Complementary methods
– Fracture location, orientation, and intensity
• Reservoir and rock property determination – Matrix quality
– Geomechanical properties
– Fluid indicators
Q & A
With Tony Rebec, Geokinetics
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