avo interpretation - visions · pdf fileavo study . since the final target is basically to...
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AVO interpretation
Vinay Sharma
2011
The main objective of this study is to better understand the possible and
delineation oil and /or gas prospect existence by improving and enhance
the seismic data on the basis of pre stack gather data.
The main work on this study include several step such as pre stack data
enhancement and post seismic signal processing, well validation, exploring
post stack seismic attributes, frequency enhancement, well data analysis
and further proposal related to the possible reservoir characterization.
Several analysis will be done in both prestack and poststack data to
increase success ratio by performing integrated analysis or integrated
deliniation.
AVO Study
Since the final target is basically to understand better the possibility of oil
and /or gas existence and delineation, thus it proposes scopes of work
which are carried out in this study as follow:
1. Pre stack data enhancement and post seismic signal processing.
2. Exploring post stack seismic attributes.
3. Frequency enhancement (seismic resolution enhancement)
4. Well data analysis and seismic inversion
5. AVO and DHI analysis
Scope of Work
Prestack seismic data
Prestack data enhancement Poststack seismic data
Poststack data enhancement
Poststack data analysis
(direct hydrocarbon analysis)
Prestack data analysis
(AVO analysis)
Well sensityvity analysis
Integrated analysis /
Integrated deliniation
Map generation and
Conclusion
General Workflow
Detailed AVO Workflow
AVO Attribute Volume
Pre STACK data
Angle Gather
Partial Angle Stack
Near Mid Far
Intercept Gradient
-
Rotate Phase
Angle
Prestack Data Enhancement
Before enhancement vs After enhancement
OFFSET GATHER LINE B04-7042 ANGLE GATHER LINE B04-7042
Prestack Data Analysis
Partial Angle (Near, Mid,Far) Stack
Prestack Data Analysis
Optimum AVO
Angle is about
27°
AVO result
TOP GAS Near Lidah (Trough)
Base GAS Near Lidah (Peak)
AVO result
AVO anomaly
Respon Well log Bisma
Near Lidah
Bisma Well
AVO result
Gradient Analysis Partial Stack (near mid far stack) Gradient Map
AVO P*G section AVO P*G map AVO P*G map derived from
partial stack
Another AVO result example
Amplitude spectrum before and after Frequency Domain enhancement
Seismic Data Frequency
Noise Frequency
Frequency Enhancement
Poststack data enhancement. Seismic section spectrum before and after Frequency Domain enhancement
Frequency Enhancement
High Frequency Enhancement
(seismic to well freq adjustment)
comparison of HFE data and original data before post enhancement
High Frequency Enhancement (seismic to well freq adjustment)
comparison of HFE data and original data after post enhancement
Well Sensitivity analysis
Well sensitivity analysis will be done before apply it to the seismic data
Direct Hydrocarbon Indicator
Sweetness Attribute
Direct Hydrocarbon Indicator
The Example of Vertical Sweetness Section which is crossing Well SG-13 whose proven of Gas
Direct Hydrocarbon Indicator
The Example of Time slice of Sweetness volume which is validated by Well SG-13 whose proven of Gas
Direct Hydrocarbon Indicator
The Example of S-transform attribute which sensitive to hydrocarbon especially gas
Analysis 1 Analysis 2 Analysis 3
Integrated Analysis
Integrated Analysis
Final Conclusion
The AVO analysis (prestack analysis) result shall be constrained by poststack analysis to increase success ratio.
All of the results will be overlaid each other to obtain best deliniation of Hydrocarbon
