Isofrequency Volume Workflow for Gas Reservoir Detection
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Solution Overview
Problem
Existing seismic survey methods struggle to accurately detect gas deposits in subterranean reservoirs, as they affect seismic waves differently than oil or water, making it difficult to identify gas-bearing regions for drilling.
Innovation Solution
Transforming relative amplitude preserved 3D seismic volumes into isofrequency volumes, extracting spectral amplitude volumes, and calculating an attribute volume to determine the presence of gas in the subterranean region by interpreting anomalies in the attribute volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional seismic survey methods are used, then the survey can be performed with standard processing, but the detection accuracy of gas deposits is insufficient
Solution Approach 1:
The patent transforms the seismic data from time-domain to frequency-domain by converting a relative amplitude preserved 3D seismic volume into multiple isofrequency volumes. This parameter transformation enables the extraction of spectral amplitude volumes at different frequencies, which enhances the ability to detect gas deposits by analyzing frequency-specific characteristics of seismic waves that differ between gas-bearing and fluid-bearing reservoirs.
Solution Approach 2:
The patent segments the seismic data processing by dividing the 3D seismic volume into multiple isofrequency volumes, then extracting specific spectral amplitude volumes (first and second isofrequency spectral amplitude volumes) for comparative analysis. This segmentation allows targeted examination of different frequency components to identify gas-related anomalies in the attribute volume.
2Reliability
If gas deposits are detected using seismic waves, then the presence of gas can be identified, but the distinction between gas and other fluids (oil or water) is difficult
Solution Approach 1:
The patent changes the domain parameter from time to frequency, creating isofrequency volumes that reveal frequency-specific characteristics of seismic wave interactions with different fluids. Gas-bearing reservoirs exhibit distinct frequency responses compared to oil or water-bearing reservoirs, and this transformation enables reliable differentiation through spectral analysis.
Solution Approach 2:
The patent adds a frequency dimension to the seismic data analysis by transforming the 3D time-domain volume into multiple isofrequency volumes. This dimensional transformation provides additional discriminatory information that enables reliable distinction between gas and other fluids based on their different effects on seismic wave frequency characteristics.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively identifies gas deposits by distinguishing gas-bearing areas through calculated attribute volumes, aiding in precise wellbore placement for gas production.
Implementation Method 1
transforming a relative amplitude preserved 3D seismic volume acquired in the time-domain into a plurality of isofrequency volumes
Implementation Method 2
extracting from the plurality of isofrequency volumes a first isofrequency spectral amplitude volume and a second isofrequency spectral amplitude volume
Data Source
AI summary
A method that includes transforming a relative amplitude preserved 3D seismic volume acquired in the time-domain into a plurality of isofrequency volumes, extracting from the plurality of isofrequency volumes a first isofrequency spectral amplitude volume and a second isofrequency spectral amplitude volume. The method further includes determining an attribute volume from the two isofrequency spectral amplitude volumes, and determining a presence of gas in a subterranean region of interest based on the attribute volume.