Seismic Node Positioning via Iterative Refinement
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Solution Overview
Problem
In shallow water seismic surveys, the reliability of direct arrival energy for positioning analysis is adversely impacted when the angle of energy departure exceeds 70 degrees, and there is limited control over node placement due to local variability in refractor velocities, leading to errors in node positioning and movement detection.
Innovation Solution
A method and system that iteratively refine the X, Y positions of ocean bottom nodes using data processing software, conditioning and analyzing seismic data to determine refined node positions regardless of energy release angles, without requiring accurate transit velocity or node depth knowledge, through an iterative looping technique that adjusts initial model positions based on statistical comparisons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If direct arrival energy is used for positioning analysis when the angle of energy departure exceeds 70 degrees, then positioning speed is maintained, but positioning reliability deteriorates
Solution Approach 1:
The patent changes the parameter used for positioning from direct arrival energy to refracted arrival energy when the angle of departure exceeds 70 degrees. This parameter substitution allows positioning to continue at high speeds while maintaining reliability by using energy paths that remain accurate at large angles.
Solution Approach 2:
The patent creates an alternative positioning method using refracted arrivals as a substitute for direct arrivals. When direct arrivals become unreliable, the system copies the positioning function using refracted energy paths, ensuring continuous reliable operation without sacrificing speed.
2Measurement precision
If iterative position refinement is performed to improve positioning accuracy, then positioning precision is improved, but processing time increases
Solution Approach 1:
The patent performs iterative position refinement only when necessary - specifically when positioning reliability would otherwise deteriorate. The iteration continues until convergence or a maximum threshold is reached, applying partial action rather than always performing full iterations, thus balancing precision with processing time efficiency.
3Adaptability or versatility
If node placement control is relaxed to accommodate local variability in refractor velocities, then adaptability to local conditions is improved, but positioning accuracy deteriorates
Solution Approach 1:
The patent changes the parameter for positioning from direct arrival time to refracted arrival time. This parameter change allows the system to adapt to local variability in refractor velocities while maintaining positioning accuracy, as refracted arrivals are less sensitive to such variations.
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 data quality by accurately determining node positions, even in shallow water environments, reducing errors and detecting node movement, thereby enhancing the reliability of seismic data analysis.
Implementation Method 1
A source, such as a vibrator unit, dynamite shot, or an air gun, generates acoustic or elastic vibrations that travel into the Earth, pass through strata with different seismic responses and filtering effects, and return to the surface to be recorded as seismic data
Data Source
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AI summary
A computing system and method for determining the x, y energy receiver (node) positions regardless of the angle at which the energy was released from the source. The process and computing system involves an iterative looping technique that is executed in data processing software wherein an initial model position based on, in essence, a best guess as to a node's location, followed with the iterative process of statistically comparing model data to actual data and then adjusting the model position by some predetermined amount and comparing this new result to the actual data to determine if the newly adjusted position is statistically better or worse than the originally selected position assumption. The process can be repeated using continuously smaller distance adjustments to the previously determined best position. Once satisfied that the true best position has been achieved, the processing can cease and the XY position data may be used in the normal course of generating seismic maps.