Seismic Imaging Earth Model Refinement via Beam Tomography
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Solution Overview
Problem
Conventional seismic imaging technologies face challenges in accurately positioning and focusing reflectors in complex subsurface structures, leading to uncertainties in hydrocarbon reservoir identification, especially when depth information is not consistently integrated into the earth model.
Innovation Solution
The method involves an iterative process of beam tomography that updates the earth model by computing traveltime variations and imposing structural constraints, using geological prior information to refocus and position reflectors accurately, thereby improving the seismic image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional seismic imaging methods are used without depth constraints, then the imaging process is simpler and faster, but the reflector positioning accuracy deteriorates and geological plausibility is compromised
Solution Approach 1:
The patent applies preliminary action by incorporating depth constraints from well data into the earth model before performing seismic imaging. This pre-constraint approach ensures that reflectors are positioned at geologically plausible depths before the imaging process begins, eliminating the need for post-imaging depth calibration and ensuring accurate reflector positioning from the start.
Solution Approach 2:
The patent changes the parameter of depth constraints by transforming well depth measurements into depth constraint surfaces that are integrated into the earth model. This parameter transformation allows the imaging process to enforce geological plausibility while maintaining computational efficiency through the use of depth constraint functions in the migration algorithm.
2Measurement precision
If depth constraints are incorporated into the earth model, then reflector positioning accuracy and geological plausibility are improved, but the device complexity and computational requirements increase
Solution Approach 1:
The patent introduces depth constraint surfaces as an intermediary between well depth data and the seismic imaging process. These constraint surfaces act as a mediator that translates discrete well depth measurements into continuous spatial constraints that can be efficiently integrated into the earth model without requiring complex iterative adjustments during imaging.
Solution Approach 2:
The earth model with integrated depth constraints serves multiple functions simultaneously: it provides the velocity structure for seismic wave propagation, enforces geological plausibility through depth constraints, and guides reflector positioning. This multi-functionality reduces the need for separate processing steps and simplifies the overall system architecture.
3Adaptability or versatility
If reflector focusing is performed without pre-stack constraints, then the imaging process is more flexible, but the image quality and hydrocarbon potential evaluation deteriorate
Solution Approach 1:
The patent applies preliminary action by pre-positioning reflectors according to depth constraints before performing stack migration. This ensures that reflectors are correctly positioned in the depth domain before focusing operations, allowing the imaging process to maintain flexibility in handling various seismic data types while ensuring high image quality through pre-established geometric accuracy.
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 results in more accurate digital seismic images that better delineate subsurface features and hydrocarbon deposits, enhancing hydrocarbon exploration and production decisions by providing precise wellbore locations, trajectories, and fluid control.
Implementation Method 1
The sources generate seismic waves, which propagate into the geological medium creating pressure changes and vibrations
Implementation Method 2
In response to the detected seismic waves, the sensors generate corresponding electrical signals, known as traces
Data Source
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AI summary
A method is described for seismic imaging that will produce a seismic image with correctly focused and positioned reflectors. This is accomplished by adding physical geological information to a beam tomography process to generate an updated earth model for the seismic imaging. The method may be executed by a computer system.