Geophysical Survey Selective-Length Sweep Processing
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Solution Overview
Problem
Geophysical surveys for oil and gas exploration face challenges in obtaining data from various depths of geological formations without increasing cost and environmental impact, as existing methods require high-energy seismic signals that can be inefficient and harmful.
Innovation Solution
A method involving a geophysical survey system that uses vibratory signal sources to perform continuous sweeps with varying sweep lengths and digital codes, allowing for selective combination of data to achieve high spatial resolution or signal-to-noise ratio depending on the depth, thereby optimizing energy use and reducing the number of signal sources needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-energy acoustic waves are used to image deep portions of geological formation, then imaging capability for deep portions is improved, but survey cost and environmental impact increase
Solution Approach 1:
The patent segments the sweep signal into multiple portions with different lengths, where longer sweep portions are used for deep imaging and shorter sweep portions are used for shallow imaging. This allows selective application of energy levels appropriate for each depth, reducing unnecessary high-energy exposure and associated environmental impact while maintaining deep imaging capability when needed.
Solution Approach 2:
The patent changes the parameter of sweep length dynamically, using longer sweeps for deep portions and shorter sweeps for shallow portions of the geological formation. This parameter variation optimizes energy efficiency and reduces environmental impact by avoiding excessive energy input for shallow imaging tasks.
2Measurement precision
If high-energy acoustic waves are used to image deep portions of geological formation, then imaging capability for deep portions is improved, but the number of signal sources required increases
Solution Approach 1:
The patent segments the sweep signal into multiple portions and processes them differently. By using longer sweep portions for deep imaging and shorter sweep portions for shallow imaging, the system achieves effective deep imaging with a single signal source, eliminating the need to deploy multiple high-energy signal sources.
Solution Approach 2:
The patent implements continuous sweeping without interruption, where the signal source continuously emits acoustic waves with varying sweep lengths. This continuous operation allows a single signal source to gather both shallow and deep imaging data over time, replacing the need for multiple signal sources operating simultaneously.
3Reliability
If longer sweep lengths are used for deep imaging, then signal-to-noise ratio for deep portions is improved, but spatial resolution for shallow portions deteriorates
Solution Approach 1:
The patent segments the sweep signal into multiple portions with different lengths. Longer sweep portions are processed to generate data for deep portions with high signal-to-noise ratio, while shorter sweep portions are processed to generate data for shallow portions with high spatial resolution. This segmentation allows each depth range to be optimized independently.
Solution Approach 2:
The patent applies different sweep lengths for different depth regions, making the sweep length a local property rather than a global one. Shallow portions use shorter sweeps for high spatial resolution, while deep portions use longer sweeps for high signal-to-noise ratio, achieving local optimization for each imaging region.
4Measurement precision
If shorter sweep lengths are used for shallow imaging, then spatial resolution for shallow portions is improved, but signal-to-noise ratio for deep portions deteriorates
Solution Approach 1:
The patent segments the sweep signal into multiple portions with different lengths. Shorter sweep portions are used for shallow imaging to achieve high spatial resolution, while longer sweep portions are used for deep imaging to achieve high signal-to-noise ratio. This segmentation allows each depth range to be optimized independently without compromise.
Solution Approach 2:
The patent dynamically changes the sweep length parameter based on the target depth. For shallow imaging, shorter sweeps provide high spatial resolution. For deep imaging, longer sweeps provide high signal-to-noise ratio. This parameter adaptation allows optimal performance for each imaging scenario.
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 enables efficient acquisition of geophysical data with improved spatial resolution and signal-to-noise ratio for different depths, reducing survey costs and environmental impact while maintaining effective imaging capabilities.
Implementation Method 1
Acoustic waves generated by the source may then be transmitted through the earth's crust and then reflected back and captured at the geophysical sensors
Implementation Method 2
Geological formations may, however, have an attenuating effect on the acoustic waves generated by the signal sources used in a geophysical survey
Data Source
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AI summary
Techniques are disclosed relating to geophysical surveying. In various embodiments, a marine survey vessel may tow a plurality of streamers that each include a plurality of seismic sensors. Further, the survey vessel may tow a plurality of vibratory sources. In various embodiments, a first sweep may be performed, using one or more of the plurality of vibratory sources, for a first time interval. Further, in various embodiments, disclosed techniques may include recording, during the first time interval using the plurality of seismic sensors, seismic data on a tangible, computer-readable medium, thereby creating a geophysical data product.