Multi-source Seismic Borehole Evaluation for Spatial Resolution
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Solution Overview
Problem
Conventional seismic exploration methods in boreholes are limited by spatial resolution, especially at great depths, due to the limited frequency band and inability to selectively excite and direct seismic waves, leading to inefficiencies in drilling and increased costs.
Innovation Solution
A seismic exploration method using a source device with at least two seismic sources in a borehole, allowing adjustable control of seismic wave radiation patterns, including frequency, phase, and amplitude, to enhance spatial resolution and focus on specific geological areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional seismic sources are used in boreholes, then the exploration can be conducted continuously during drilling, but the spatial resolution deteriorates at great depths due to limited frequency band
Solution Approach 1:
The patent divides the single seismic source into multiple independent seismic sources (at least two) that can be positioned at different locations within the borehole. This segmentation allows for more flexible wave generation and reception geometries, enabling high-frequency signal generation even at great depths by optimizing the spatial arrangement of sources and receivers relative to target formations.
Solution Approach 2:
The patent transitions from conventional single-point source excitation to multi-point source excitation with receivers positioned at multiple locations. This dimensional expansion in source-receiver configuration enables sophisticated wavefield illumination and reception patterns that maintain high spatial resolution at depth by creating optimized measurement geometries.
2Adaptability or versatility
If conventional borehole sources are used, then both P-waves and S-waves are generated simultaneously, but the temporal superposition of these wave types leads to errors in evaluation
Solution Approach 1:
The patent extracts and separates the generation of different wave types by using multiple independent seismic sources that can be individually controlled. This allows for selective excitation of either P-waves or S-waves from specific source locations, preventing the temporal superposition problem that occurs when both wave types are generated simultaneously by a single source.
Solution Approach 2:
The patent introduces dynamic control over wave type generation by enabling independent activation and parameter control of multiple seismic sources. This dynamic capability allows the system to selectively generate only the desired wave type (P-wave or S-wave) from specific sources, providing temporal and spatial separation that eliminates superposition errors in wave evaluation.
3Adaptability or versatility
If conventional seismic exploration methods are used, then the frequency band is limited up to approximately 200 Hertz, but this results in insufficient spatial resolution for deep target horizons
Solution Approach 1:
The patent fundamentally changes the frequency parameter by using multiple seismic sources capable of generating a broad frequency spectrum extending well beyond the conventional 200 Hz limit. This parameter change enables high-frequency signal generation that provides the short wavelengths necessary for high spatial resolution imaging of deep target horizons, while the multiple source configuration allows optimization of frequency content for different depth ranges.
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
Enables high-resolution, three-dimensional imaging of the borehole environment down to the decimeter range, allowing adaptive drilling and reducing the need for costly multiple drilling operations by providing precise geological data.
Implementation Method 1
A borehole source is inserted into the borehole and generates elastic waves that are radiated into the vicinity of the source's point of impact
Implementation Method 2
These waves are recorded by receivers such as geophones or hydrophones at various locations after they have traversed the subsurface strata and been reflected by stratigraphic boundaries or scattered by material inhomogeneities
Implementation Method 3
These waves are recorded by receivers such as geophones or hydrophones at various locations after they have traversed the subsurface strata and been reflected by stratigraphic boundaries or scattered by material inhomogeneities
Implementation Method 4
These waves are recorded by receivers such as geophones or hydrophones at various locations after they have traversed the subsurface strata
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 3
AI summary
The invention relates to a method for seismic evaluation, in particular of the vicinity of a bore (1) in a geological formation (2). Said method comprises the following steps: provision of a source system (10) comprising at least two seismic sources (11) in the bore (1); generation of seismic waves that propagate in the geological formation (2) with predefined emission characteristics formed by the two or more seismic sources (11); and recording of the seismic waves using a recording system (20). The invention also discloses a seismic system (100) for seismic evaluation of the vicinity of a bore in a geological formation, comprising a source system (10) with at least two seismic sources (11), said source system having predefined emission characteristics and being positionable in the bore (1), and comprising a recording system (20) that can record seismic waves in the vicinity of the bore (1).