Real-Time Reflection Point Density Mapping for 3D VSP Surveys
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Solution Overview
Problem
Current methods for acquiring 3D vertical seismic profiles (VSPs) are time-consuming and costly, often resulting in incomplete data sets due to the need for extensive rig time, weather interruptions, and equipment malfunctions, with existing binning techniques relying on post-acquisition data manipulation and assuming availability of adjacent reflection point data, which can lead to compromised data quality and uneven reflection point density.
Innovation Solution
The method involves real-time reflection point density mapping using one-way transit times to adjust surface source points and firings, ensuring each bin meets a desired reflection point density, thereby optimizing data acquisition and avoiding the need for post-acquisition data manipulation by generating additional data where needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional VSP acquisition methods are used with fixed source intervals and locations, then the survey can be completed with a predetermined plan, but the data quality may be insufficient in certain areas due to uneven reflection point density
Solution Approach 1:
The system continuously monitors reflection point density during the survey and uses this feedback to dynamically adjust source firing locations and intervals, ensuring optimal data quality without requiring excessive survey time
Solution Approach 2:
The survey methodology transitions from static predetermined source locations to dynamic real-time adjustment of source positions based on actual reflection point density measurements, allowing the system to adapt to subsurface variations
2Reliability
If additional source firings are performed to improve reflection point density in specific bins, then data quality improves, but the survey time and costs increase
Solution Approach 1:
The system applies different source firing strategies to different spatial bins based on their specific reflection point density requirements, concentrating additional firings only where needed rather than uniformly across the entire survey area
Solution Approach 2:
The system performs preliminary reflection point density calculations and identifies bins requiring additional coverage before executing the survey, allowing proactive optimization rather than reactive corrections
3Loss of information
If post-acquisition binning techniques are used to compensate for insufficient data, then incomplete data sets can be partially recovered, but the reflection point density remains uneven and data accuracy is compromised
Solution Approach 1:
The system performs preliminary reflection point density mapping and identifies data gaps before they become critical, allowing corrective source firings to be made while the survey is still ongoing rather than attempting post-hoc corrections
Solution Approach 2:
The survey system self-corrects for insufficient data by automatically identifying bins with low reflection point density and triggering additional source firings in those specific areas, eliminating the need for external post-processing interventions
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 allows for more efficient and cost-effective acquisition of high-quality 3D VSP data by ensuring real-time assurance of reflection point density, reducing the need for additional field visits and enhancing data accuracy by directly addressing uneven coverage during the survey.
Implementation Method 1
Seismic energy travels downwardly from one or more seismic sources and is reflected from acoustic impedance boundaries below the surface of the earth
Implementation Method 2
The actual coordinates or locations of the source firings are more accurately accounted for using a GPS system
Implementation Method 3
In real time, one-way transit times are used to generate reflection point density maps for bins of the target reflector
Data Source
AI summary
Methods and apparatuses are disclosed for generating three dimensional (3D) vertical seismic profiles (VSPs) in a more time efficient manner. The methods and apparatuses enable faster and more efficient VSP surveys than previous techniques. Real-time updating of the velocity model and real-time reflection point density calculations are carried out, which are used to determine the location of the next seismic source firing. In the event the data of a particular bin has an insufficient fold, common image points (CIPs) or reflection point density, additional source firings may be carried out prior to moving the source. Further, in the event the data of a particular bin is excessive in terms of the fold, CIPs or reflection point density before the planned source firings for the bin are completed, remaining source firings for that bin may be skipped to save time and improve the efficiency of the data collection.