Frequency Ratio Seismic Volumes for 3D Gas Reservoir Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing seismic methods struggle to reliably identify gas-bearing reservoirs due to variations in reservoir thickness and impedance, making high-frequency seismic wave amplitudes unreliable indicators for hydrocarbon presence.
Innovation Solution
A method and system that utilize spectral decomposition of seismic data to generate single-frequency volumes, calculate frequency ratios, and extract a 3D geological body based on these ratios, enabling precise localization of gas reservoirs by analyzing the attenuation of high-frequency seismic waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If high-frequency seismic wave amplitudes are used to identify gas-bearing reservoirs, then the detection capability is improved, but the reliability deteriorates due to variations in reservoir thickness and impedance
Solution Approach 1:
The patent transforms the seismic data from time domain to frequency domain through spectral decomposition, changing the parameter representation from time-amplitude to frequency-content. This allows analysis of frequency ratios instead of absolute amplitudes, making the detection more reliable by eliminating the influence of reservoir thickness and impedance variations while preserving the ability to detect gas-bearing zones through frequency attenuation patterns
2Measurement precision
If spectral decomposition is applied to obtain single-frequency volumes, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent extracts only the necessary frequency information from the full spectral decomposition by focusing on the ratio between high-frequency and low-frequency components. Instead of analyzing the complete frequency spectrum, the method isolates and compares specific frequency bands, reducing computational complexity while maintaining the precision benefits of spectral decomposition for identifying gas-bearing reservoirs
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
Enhances the precision of identifying gas deposits and optimizing drilling operations by reducing the risk of drilling in water-saturated regions, improving wellbore trajectory planning and hydrocarbon extraction efficiency.
Implementation Method 1
Acquired seismic data may include a wide range of frequencies. Spectral decomposition may be applied to seismic data to obtain data volumes corresponding to discrete frequency values.
Implementation Method 2
The presence of gas in the pores of a geological formation are known to affect the attenuation of seismic waves. Attenuation is known to affect the amplitude of high frequency seismic waves more than the amplitude of low frequency seismic waves.
Data Source
AI summary
Examples of methods and systems are disclosed. The methods include, obtaining a seismic dataset regarding a subsurface region of interest, wherein the seismic dataset comprises a plurality of time-domain seismic traces. The methods also include determining a plurality of single-frequency volumes from the plurality of time-domain seismic traces. The methods further include determining a frequency ratio volume based, at least in part, on the plurality of single-frequency volumes. The methods still further include extracting a three-dimensional (3D) geological body based, at least in part, on the frequency ratio volume. The methods further include determining a drilling target in the subsurface region based on the 3D geological body.