Download presentation

1
**Geol 755: Basin Analysis Geophysics Week 6**

John N. Louie, Presenter Tuning Phenomena in Reservoirs Effect of Tuning on Stratigraphic Interpretation Deterministic Tuning Curves Statistical Tuning Curves Understanding the Magnitude of Tuning Effects Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

2
**Effect of Tuning on Stratigraphic Interpretation**

When bed thickness ≥ , top and base reflections are separate. When bed thickness < , reflections interfere and resonate- tuning Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

3
**Effect of Tuning on Stratigraphic Interpretation**

Where reflections merge, amplitude increases Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

4
**Effect of Tuning on Stratigraphic Interpretation**

In vertical and horizon section, amplitudes are highest where bed is thin- at the the tuning thickness. Merged downdip reflections average the dip of the reservoir top & base. Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

5
**Effect of Tuning on Stratigraphic Interpretation**

The limit of visibility depends on thickness as well as impedance contrast, and noise level Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

6
**Deterministic Tuning Curves**

Have to differentiate tuning effects from variations in properties (like porosity and fluid content) Tuning is a purely geometric effect The ideal tuning thickness is /4 Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

7
**Deterministic Tuning Curves**

Sidelobes of wavelets also tune for thicker intervals Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

8
**Deterministic Tuning Curves**

Different wavelets will tune to different degrees May be multiple maxima on the tuning curve Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

9
**Statistical Tuning Curves**

Can cross-plot amplitudes from related locations to examine correlations Linearity here suggests changes within reservoir, not outside Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

10
**Statistical Tuning Curves**

Reflection amplitude against interpreted thickness Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

11
**Statistical Tuning Curves**

Reflection amplitude against interpreted thickness The envelope is a statistical tuning curve Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

12
**Statistical Tuning Curves**

Reflection amplitude against interpreted thickness The envelope here follows a percentile of amplitudes Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

13
**Statistical Tuning Curves**

Reflection amplitude against interpreted thickness The envelope here is compared with a deter-ministic curve Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

14
**Understanding the Magnitude of Tuning Effects**

Wavelet shape is critical to knowing where tuning is occurring. Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

15
**Understanding the Magnitude of Tuning Effects**

Wavelet shape is critical to knowing where tuning is occurring. Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

16
**Understanding the Magnitude of Tuning Effects**

“The first side lobe as a fraction of the center lobe of a zero-phase wavelet is the reciprocal of the octave bandwidth.” Good seismic data has 2.5 octaves, for a side lobe level of 40% relative to the center. This “40% rule” means that 40% is a common increase in amplitude at tuning for zero phase wavelets, reflected from the top and base of a reservoir layer. Greater increases in amplitude must be explained otherwise. Taken From: Alistair R. Brown, AAPG Memoir 42, Interpretation of Three-Dimensional Seismic Data, 4th & 6th Editions

Similar presentations

OK

Well-Seismic Ties Lecture 7 Depth Time Synthetic Trace SLIDE 1

Well-Seismic Ties Lecture 7 Depth Time Synthetic Trace SLIDE 1

© 2018 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Download ppt on energy and environment Ppt on standing order meaning Ppt on search engine google Ppt on 60 years of indian parliament structure Ppt on ngos in india Ppt on source code theft Ppt on fdi and fii in india Ppt on famous indian entrepreneurs in Ppt on air pressure and wind system Ppt on online shopping in php