Seismic Attribute Mapping for Accurate Subsurface Gas Detection
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Solution Overview
Problem
Existing seismic surveys struggle to accurately detect gas deposits within subterranean reservoirs due to their impact on seismic wave characteristics, making it difficult to drill effective wells for gas extraction.
Innovation Solution
A method involving seismic attribute mapping, which includes processing seismic data to generate a relative amplitude preserved 3D seismic volume, transforming it into low-frequency monospectral amplitude and seismic attenuation volumes, and creating an attribute map by combining these volumes to identify gas deposits, facilitating well planning and drilling.
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 accuracy of gas deposit detection is insufficient due to gas affecting seismic wave characteristics
Solution Approach 1:
The patent transforms the seismic volume into different attribute volumes (low-frequency monospectral amplitude volume, seismic attenuation volume) by changing the physical parameters and frequency characteristics of the seismic data. This allows detection of gas deposits by analyzing how gas affects these transformed parameters rather than relying on conventional seismic wave characteristics that are distorted by gas presence.
Solution Approach 2:
The patent introduces seismic attribute maps as intermediary representations between the raw seismic data and gas deposit detection. These attribute maps (low-frequency monospectral amplitude map, seismic attenuation map) serve as mediators that highlight gas-related anomalies by transforming and emphasizing specific physical properties affected by gas presence.
2Productivity
If conventional seismic processing is used, then the processing workflow remains simple, but the ability to identify gas deposits and plan wells is insufficient
Solution Approach 1:
The patent segments the seismic processing into distinct stages: generating the seismic volume, transforming it into specific attribute volumes (low-frequency monospectral amplitude, seismic attenuation), and combining them into an integrated attribute map. This segmentation allows each transformation to target specific gas-related characteristics, improving detection capability while maintaining a systematic and manageable processing workflow.
3Measurement precision
If standard seismic attributes are used, then the attribute analysis remains straightforward, but the detection of gas-bearing reservoirs is inaccurate
Solution Approach 1:
The patent adds new dimensions to the seismic analysis by transforming the 3D seismic volume into multiple attribute volumes with different physical meanings (amplitude, attenuation, frequency characteristics). By combining these multi-dimensional attribute maps, the method recovers and emphasizes information about gas presence that is distributed across different attribute dimensions, thereby improving detection accuracy without losing critical seismic information.
Data Source
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AI summary
A method of obtaining a relative amplitude preserved seismic volume acquired in a time-domain for a subterranean region of interest and transforming it into a low- frequency monospectral amplitude volume. The method further determines a seismic attenuation volume from the relative amplitude preserved seismic volume acquired in the time-domain. Furthermore, the method generates a low-frequency monospectral amplitude map for a surface of interest by averaging the low- frequency monospectral amplitude volume over a depth-window around the surface of interest, and generates a seismic attenuation map for a surface of interest by averaging the seismic attenuation volume over a depth-window' around the surface of interest. The method further determines an attribute map based on the seismic attenuation map and the low-frequency monospectral amplitude map for the surface of interest, and determines a presence of gas in the subterranean region of interest based on the attribute map.