Seismic Water Property Estimation Using Coherence Analysis
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Solution Overview
Problem
Marine seismic surveys face challenges in accurately determining water properties such as velocity and source height due to uncertainties, which affect the positioning of subterranean structures like petroleum reservoirs, as these properties change over time and with varying water conditions.
Innovation Solution
A method is developed to estimate water properties by calculating travel times for seismic events, aligning data values, and determining coherence values using semblance analysis, allowing for precise determination of undetermined water property values like velocity and source height, thereby improving the accuracy of seismic data interpretation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional seismic survey methods are used, then water properties can be obtained through manual processing, but the labor costs are high and processing efficiency is low
Solution Approach 1:
The system enables automatic estimation of water properties (velocity and source height) through self-service processing of seismic data. The computer automatically performs travel time calculations, coherence analysis, and property estimation without requiring manual intervention, thereby eliminating labor-intensive processing while maintaining high accuracy.
Solution Approach 2:
The patent replaces manual mechanical processing with automated computational methods. Instead of human analysts manually measuring travel times and calculating water properties, the system uses computer algorithms to automatically process seismic data, calculate coherence values, and estimate water properties, thereby reducing labor costs and increasing processing efficiency.
2Measurement precision
If water properties are not accurately determined, then seismic survey speed can be maintained, but the positioning accuracy of subterranean structures deteriorates
Solution Approach 1:
The system performs preliminary estimation of water properties (velocity and source height) directly from the seismic data before final interpretation. By calculating travel times and coherence values in advance, the system establishes accurate water property parameters that are then used to correctly position subterranean structures, thereby improving measurement precision without requiring additional survey time.
Solution Approach 2:
The system uses coherence analysis to evaluate the quality of travel time measurements and iteratively refines the estimation of water properties. The coherence values provide feedback on the accuracy of preliminary estimates, allowing the system to adjust and optimize water property parameters until maximum coherence is achieved, thereby ensuring high positioning accuracy.
3Measurement precision
If manual processing methods are used, then detailed analysis can be performed, but the labor costs increase and processing becomes more complex
Solution Approach 1:
The patent replaces complex manual processing procedures with automated computer-based algorithms. The system automatically performs travel time measurements, coherence calculations, and water property estimations that would otherwise require skilled manual analysis, thereby maintaining high measurement precision while significantly reducing processing complexity and labor requirements.
Solution Approach 2:
The system performs self-service processing by automatically analyzing seismic data to estimate water properties without requiring manual intervention. The computer autonomously calculates travel times, evaluates coherence values, and determines water velocity and source height, thereby achieving detailed analysis with minimal human involvement and reduced processing complexity.
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 enhances the accuracy of water property estimation, reducing labor costs and improving the reliability of seismic surveys by providing robust and non-labor-intensive data processing, applicable to both single and time-lapse 4D seismic surveys.
Implementation Method 1
Each acoustic signal is essentially a sound wavefield that travels through the water
Implementation Method 2
The seismic receivers thereby measure a wavefield that was ultimately initiated by the actuation of the seismic source
Data Source
AI summary
A method for estimation of water properties from seismic data can include determining a number of travel times for at least one event based, at least in part, on predefined values for a plurality of water properties, determining an alignment of data values for each of the number of travel times determined for the at least one event, and determining an estimation of a plurality of undetermined water property values based, at least in part, on the alignment of the data values for each of the number of travel times producing a high quantitative measure of a coherence value.