Embed Size (px)
Citation preview
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
1
A new method to calculate
pore pressure
from stacked seismic data
QProtected by US Patent No. 6,681,185
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
2
Q stands for Quality Factor
Q is the inverse of attenuation
Q-Based Pore Pressure
What is Q?
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
3
Numerous authors have reported on the experimental
relationship between Qp and Pressure (Peff stress ,Pp) .
Birch and Bancroft
Johnston et al
Lucet and Zinszner
Best and Sams
Carcione
Siggins and Dewhurst
Experimental Results
Such as:
With results like this
1938
1979
1992
1997
2000
2001
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
4
Lab Results
OTC 13043
Stress Path, Pore Pressure and Microstructural Influences on Q in Carnarvon
Basin Sandstones
A.F. Siggins and D.N. Dewhurst (CSIRO Petroleum, Australia) and P.R. Tingate (National
Centre for Petroleum Geology and Geophysics, University of Adelaide, Australia).
5% Change 150% Change
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
5
An Intuitive Explanation
Q-Based Pore Pressure
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
6
Q-Based Shale Pore Pressure
Hi Q
Frequency
Low Q
Frequency
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
7
Q Responds to Effective Stress
Normal Pressure
Over PressureEffective
stress
Pore
Pressure
Frequency
Hi Q
Frequency
Frequency
Low Q
Frequency
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
8
Procedure
Q-Based Pore Pressure
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
9
Q-Based PP Procedure
Frequency
Decay Pore Pressure
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
10
Deep Water Frequency Trend
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
PP-V Calibration
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
PP-Q Calibration
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
13
Q-Based Shale PP
Calibrated PP from seismic frequencies
Well B Well A
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
14
Why Use Two Methods to
Calculate PP?
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
15
Q-Based Shale PP
Calibrated PP from seismic frequencies
Well B Well A
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
16
V-Based Shale PP
Calibrated PP from seismic velocities
Well B Well A
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
17
Velocity Responds to LithologyD
epth
DT
Sand Trend
Shale Trend
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
18
Examples
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
19
Water Bottom
Shale
Moderate
Sand/Shale
Ratio
Steep Structure
Causing
Seismic Velocity Issues
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
20
Water Bottom
PP-Q
PP-V
Sandy and Tight
Shaley
Clastics
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
21
PP-V PP-Q
Shale
Sandy
Shale
Carbonate
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
22
PP-Q
PP-V
LIFGNow including a lithology influenced frac-gradient, LIFG.
www.e-seis.com Copyright 2002-2020 eSeis, Inc. All rights reserved.
23
Using Multiple Pore Pressure Prediction
Techniques provides a way to mitigate
risk.
Conclusion
