Frequency Dispersion Correction in Seismic Logging Data
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Solution Overview
Problem
The seismic exploration technology faces limitations in resolving deep carbonate formations due to insufficient resolution and low signal-to-noise ratios, particularly in the Chinese western basins, where frequency dispersion between seismic and logging data introduces uncertainty and errors in reservoir identification and fluid distribution analysis.
Innovation Solution
A method and system that test core samples to obtain logging and seismic band velocities under different pressures, fitting relationships between stratum pressure and velocity to eliminate frequency dispersion effects, using a processor and computer program to process data and correct for velocity mismatches between seismic and logging data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acoustic logging data and seismic data are combined for deep carbonate exploration, then the vertical resolution is improved, but frequency dispersion causes velocity mismatch and increases uncertainty
Solution Approach 1:
The patent applies parameter changes by systematically varying pressure conditions during core sample testing to obtain velocity data at different pressure levels. This allows establishing pressure-velocity relationships that account for frequency dispersion effects, enabling accurate velocity conversion between logging and seismic frequency bands while maintaining both resolution and reliability
Solution Approach 2:
The patent introduces pressure as an intermediary parameter to bridge the velocity mismatch between logging and seismic data. By using pressure-controlled core testing to establish transfer relationships, the method mediates the frequency dispersion effect and enables accurate velocity conversion without direct frequency mixing
2Reliability
If frequency dispersion characteristic values are estimated by adjusting acoustic logging velocity, then data mismatch can be reduced, but the accuracy cannot be ensured due to reliance on technician experience
Solution Approach 1:
The patent implements self-service by having the system automatically determine frequency dispersion characteristics through systematic pressure-controlled testing and mathematical fitting. The method eliminates reliance on technician experience by using objective measurement data and algorithmic processing to derive accurate velocity conversion relationships
Solution Approach 2:
The patent applies feedback by using the established pressure-velocity relationships to continuously refine and verify velocity conversion accuracy. The method creates a closed-loop system where measurement results feed back into the model to improve subsequent conversions, ensuring both data consistency and measurement precision
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 approach improves the accuracy of reservoir representation and fluid distribution analysis by enhancing time-depth matching, reducing uncertainty, and increasing the reliability of seismic-logging data consistency, leading to improved drilling success rates and resource estimation.
Implementation Method 1
According to the porous media theory, the underground rock pores contain oil, gas or salt water, so when waves of different frequencies are propagated therein, there occurs a phenomenon that the velocity varies with the frequency, i.e., the 'frequency dispersion' effect.
Data Source
AI summary
The present disclosure disclose a method, an apparatus and a system for eliminating a frequency dispersion effect, wherein the method comprises: testing a core sample to obtain logging band velocities and seismic band velocities under different pressures; fitting a relationship between a stratum pressure and the logging band velocity using the logging band velocities under different pressures, and fitting a relationship between the stratum pressure and the seismic band velocity using the seismic band velocities under different pressures; and eliminating a frequency dispersion effect in a target area using the relationship between the stratum pressure and the logging band velocity and the relationship between the stratum pressure and the seismic band velocity.