Geological Structural Trend Prediction via Fault Dip Correction
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Solution Overview
Problem
In remote or frontier areas with limited subsurface data, determining structural trends of geological structures is challenging due to sparse data availability, leading to uncertainty in resource estimates and unnecessary expenditure in exploration programs.
Innovation Solution
A computer-implemented method that uses a single cross section with visible geological fault markers to measure fault inclination, convert seismic data to depth, correct for vertical exaggeration, and determine structural style and true fault inclination, thereby estimating the structural trend by calculating the angle of obliquity between observed and actual trends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If widely-spaced 2D reflection seismic lines are used in remote areas, then data acquisition cost is reduced, but structural trend determination becomes uncertain
Solution Approach 1:
The patent transforms the problem from 2D cross-section analysis to 3D structural trend determination by introducing the concept of out-of-plane dip components. By calculating the apparent dip angle and combining it with the known strike direction, the system derives the true dip direction and magnitude in three-dimensional space, enabling accurate structural trend determination even from sparse 2D data.
Solution Approach 2:
The patent uses the apparent dip angle measured from 2D cross-sections as an intermediary parameter to derive the true structural trend. By treating the apparent dip as a mediator that can be mathematically transformed using trigonometric relationships and the known strike direction, the system bridges the gap between limited 2D observations and comprehensive 3D structural understanding.
2Measurement precision
If more 2D seismic lines are acquired to constrain structural trends, then structural trend determination accuracy improves, but exploration cost increases
Solution Approach 1:
The patent changes the analytical parameters by introducing the strike direction as a known constraint and using apparent dip angle measurements in combination with strike information. This parameter transformation allows the system to calculate true dip direction and magnitude without requiring additional seismic lines, thereby maintaining measurement precision while reducing the quantity of data acquisition needed.
3Loss of time
If initial resource estimates are made without knowledge of structural trends, then exploration program can start earlier, but uncertainty in resource estimates increases
Solution Approach 1:
The patent performs preliminary structural trend determination by analyzing the apparent dip angle and strike direction from existing 2D cross-section data before conducting full resource estimation. This preliminary action provides sufficient structural constraint to reduce uncertainty in initial resource estimates, enabling the exploration program to start earlier with improved reliability.
Data Source
AI summary
Systems and methods include a computer-implemented method for identifying geological structural trends. A cross section with visible geological fault markers for geological structures is received. An angle of inclination of a fault is measured. An average seismic velocity to convert z-axis values from a two-way travel time to a depth is determined. A depth conversion is implemented. A horizontal scale and a vertical scale are compared to determine an aspect ratio of a depth section of the cross section, including determining a vertical exaggeration. The aspect ratio of the depth section is corrected for the vertical exaggeration to obtain an accurate measurement of fault inclination in the cross section. A structural style and an expected true fault inclination are determined for the depth section. An angle of obliquity and a structural trend are determined using the expected true fault inclination compared with the measured angle of inclination of the fault.