Converted Mode Seismic Survey Design for Resolution
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Solution Overview
Problem
Current methods for designing converted mode seismic surveys lack the development and completeness to achieve specified seismic image resolution objectives, particularly due to differences in incident and reflected wave modes, which are not adequately addressed by existing common mode seismic survey design procedures.
Innovation Solution
A method for designing converted-wave seismic surveys that involves selecting desired vertical and lateral seismic resolutions, determining minimum source frequency bandwidth, migration acceptance angle, and bin size requirements, and calculating source and receiver spacings to achieve specified resolution criteria at target depths, using P-wave and S-wave velocities and scattering angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If common mode seismic survey design procedures are used for converted mode surveys, then the design process is simplified, but the seismic image resolution objectives cannot be achieved due to differences in wave modes
Solution Approach 1:
The patent applies parameter changes by modifying the survey design parameters specifically for converted mode surveys. It determines minimum source frequency bandwidth, migration acceptance angle, and bin size requirements that are tailored to converted mode wave propagation characteristics, rather than using standard common mode parameters. This resolves the contradiction by adapting parameters to achieve both operational feasibility and resolution objectives.
Solution Approach 2:
The patent segments the survey design process into distinct steps: determining minimum source frequency bandwidth, determining migration acceptance angle and source/receiver apertures, and determining maximum bin size. Each segment addresses specific aspects of converted mode survey design, allowing systematic optimization of resolution while maintaining practical operability.
2Reliability
If converted mode seismic surveys are implemented to achieve better imaging in challenging conditions, then imaging capability improves, but the survey design becomes more complex due to mode conversion requirements
Solution Approach 1:
The patent manages design complexity by systematically determining specific parameters for converted mode surveys: minimum source frequency bandwidth based on vertical resolution objectives, migration acceptance angle and corresponding apertures for lateral resolution, and maximum bin size to prevent aliasing. This structured parameter determination approach makes the complex converted mode design process more manageable while maintaining improved imaging capability.
3Manufacturing precision
If source and receiver spacing is reduced to improve lateral resolution, then lateral seismic resolution improves, but the survey coverage area increases and acquisition time extends
Solution Approach 1:
The patent determines migration acceptance angle and corresponding source and receiver apertures that provide sufficient lateral resolution without requiring excessive coverage. By calculating the minimum necessary apertures based on resolution objectives, the design achieves adequate lateral resolution while avoiding unnecessary expansion of survey coverage area and acquisition time.
Solution Approach 2:
The patent performs preliminary determination of migration acceptance angle and apertures before finalizing the survey design. This advance calculation of required source and receiver spacings allows optimization of the balance between lateral resolution and coverage efficiency before field implementation.
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 the design of converted-mode seismic surveys that effectively achieve specified seismic image resolution objectives, allowing for the identification of formations likely to contain hydrocarbons and informing well placement for extraction.
Implementation Method 1
A P-wave is excited by the source and propagates into the earth where it is reflected (or scattered) back from the earth and recorded by receivers
Implementation Method 2
a receiver, or distribution of receivers, that records the wave that is reflected (or scattered) back from the earth
Implementation Method 3
an S-wave is excited by the source and propagates into the earth where it is reflected (or scattered) back from the earth and recorded by receivers
Implementation Method 4
An example is PS reflection seismology, where a P-wave is excited by the source and propagates into the earth, and an S-wave is reflected (or scattered) back from the earth and recorded by receivers
Implementation Method 5
Another example is SP reflection seismology, where an S wave is excited by the source and propagates into the earth, and a P-wave is reflected (or scattered) back from the earth and recorded by receivers
Data Source
AI summary
Method for designing a converted mode (PS or SP) seismic survey to accomplish specified vertical and lateral resolution objectives at target depth. An equation (181) is provided for determining the minimum bandwidth required for a desired vertical resolution at a selected scattering angle, as a function of incident and reflected wave velocities, one of which is the P-wave velocity and the other is the S-wave velocity. A second equation (182) is provided for determining migration acceptance angle from the desired vertical and lateral resolutions. Source and receiver apertures may then be determined by ray tracing. Finally, a third equation (183) is provided for the maximum bin size to avoid aliasing, given the migration acceptance angle and a maximum frequency needed to achieve the bandwidth requirement. Source and receiver spacing may then be based on the maximum bin size.