Seismic Transfer Function for Time-Lapse Change Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current 4-D seismic survey methods are costly and complex, particularly when dealing with passive seismic monitoring, as they require precise instrument positioning and data processing that is difficult to repeat, and struggle with nonrepeatable energy sources and overlapping seismic energy from different strata.
Innovation Solution
The method involves computing a transfer function to transform shaping filters from one seismic data set to another, allowing for relative change measurement within traces rather than absolute differences, which cancels out wavelet effects and enables spatial interpolation of time-lapse changes, facilitating quicker and less costly mapping of subsurface changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional 4-D seismic survey methods are used to detect subsurface changes, then measurement precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent extracts and removes the shaping filter component from the seismic data processing pipeline. By computing a transfer function that transforms the shaping filter of one survey to another, the method eliminates the need for precise instrument positioning and coupling requirements, thereby reducing device complexity while maintaining measurement precision for subsurface change detection
Solution Approach 2:
The patent changes the parameter representation from absolute amplitude values to relative change measurements. By focusing on relative changes within traces and using transfer functions to normalize data between surveys, the method reduces sensitivity to acquisition parameter variations, simplifying the processing requirements while preserving detection precision
2Measurement precision
If precise instrument positioning and data processing are required for 4-D seismic surveys, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent performs preliminary normalization by computing transfer functions that transform shaping filters between surveys before the main analysis. This preliminary action accounts for variations in instrument positioning and coupling characteristics in advance, allowing subsequent processing to focus only on subsurface changes, thereby reducing overall processing time while maintaining precision
Solution Approach 2:
The patent creates a transformed copy of the shaping filter from one survey to another through the transfer function. This copying approach allows the method to work with normalized data that already accounts for acquisition variations, eliminating the need for time-consuming precise positioning and processing steps while preserving measurement precision
3Adaptability or versatility
If traditional methods are used for passive seismic monitoring, then adaptability is improved, but measurement precision deteriorates due to nonrepeatable energy sources
Solution Approach 1:
The patent introduces a transfer function as an intermediary that mediates between the nonrepeatable passive seismic energy sources and the analysis process. This transfer function transforms and normalizes the data from different surveys, allowing precise change detection despite the inherent nonrepeatability of passive energy sources, thereby maintaining both adaptability and measurement precision
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Systems and methods for monitoring time-dependant subsurface changes from imperfectly repeated data measurements.