Reference RGT Surface Reconstruction for Faulted Seismic Images
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining chrono-stratigraphic representations of geological formations, such as RGT images, fail to accurately account for prior knowledge about the geological formation, particularly in the presence of faults, leading to inaccuracies in seismic horizon surface determination.
Innovation Solution
A method that incorporates prior knowledge by using setpoints derived from well bore measurements or human interpretation to retrieve RGT surfaces, and combines these surfaces using weighted coefficients based on horizontal distance to determine a reference RGT surface, ensuring accuracy even in the presence of faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a regular grid is used for computing seismic horizon surfaces, then computational complexity is reduced through fast Fourier transforms, but the ability to incorporate prior knowledge about fault locations and seismic reflectors is lost
Solution Approach 1:
The patent divides the computational domain into multiple segments or regions, each processed independently to allow incorporation of local prior knowledge about faults and reflectors. This segmentation enables the use of fast Fourier transforms within each segment while maintaining the ability to integrate geological constraints, thus resolving the contradiction between computational speed and accuracy.
Solution Approach 2:
The patent applies different processing strategies to different regions of the seismic image based on local geological characteristics. In regions with known faults or reflectors, the processing incorporates these prior knowledge constraints, while in other regions, standard fast Fourier transform methods are used. This local differentiation maintains both computational efficiency and geological accuracy.
2Reliability
If prior knowledge about fault locations and seismic reflectors is incorporated, then the accuracy of seismic horizon surface determination is improved, but the computational complexity increases
Solution Approach 1:
The patent performs preliminary identification and marking of fault locations and seismic reflector positions before the main computational process. By pre-processing the geological constraints and integrating them into the computational framework in advance, the patent reduces the complexity of the main processing step while maintaining high accuracy in seismic horizon surface determination.
3Measurement precision
If iterative searching is performed to find surfaces with local gradients approaching local seismic dips, then RGT surfaces can be determined, but the method performs poorly in the presence of faults
Solution Approach 1:
The patent applies preliminary corrections or adjustments to the iterative searching process in regions where faults are expected or detected. By anticipating and counteracting the negative effects of faults on the iterative gradient-based method, the patent maintains both precision in RGT surface determination and robustness in fault-prone areas.
Data Source
AI summary
A computer-implemented method for processing a seismic image obtained from seismic measurements performed on a geological formation includes determining a relative geological time (RGT) image based on the seismic image; obtaining setpoints for the RGT image; retrieving an RGT surface of the RGT image for each of the setpoints, wherein each point of an RGT surface is defined by a vertical position and at least one horizontal position; and determining a reference RGT surface by combining the RGT surfaces determined for the setpoints. The vertical position of a point of the reference RGT surface is obtained by combining the vertical positions of the points of the RGT surfaces having the same at least one horizontal position as the considered point of the reference RGT surface. The combining of the vertical positions uses weighting coefficients.