Full-Waveform Sonic Imaging for Reservoir Structure Determination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional borehole sonic imaging methods rely on static velocity models that ignore formation changes away from the well, leading to distorted images and inadequate reflection imaging, especially in horizontal or extended-reach wells where structural assumptions differ from actual geology, and lack sufficient information for accurate velocity modeling.
Innovation Solution
A method that collects full-waveform sonic data to create a dynamic 2D or 3D velocity model integrating data from the borehole and offset wells, transforming it into a borehole-centric coordinate system for iterative imaging and velocity model updates using pre-stack depth migration techniques like Reverse-Time Migration or Generalized Radon Transform, allowing for accurate imaging of geological structures away from the borehole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional static velocity models are used for sonic imaging, then the imaging process is simple and fast, but the image resolution and accuracy deteriorate due to ignoring formation changes away from the borehole
Solution Approach 1:
The patent transitions from static velocity models to dynamic velocity models that are continuously updated using iterative imaging processes. The velocity model evolves alongside the imaging process, incorporating reflections and updates at each iteration to accurately represent formation changes away from the borehole, thereby resolving the contradiction between image resolution and model complexity.
Solution Approach 2:
The patent implements feedback mechanisms where the imaging process continuously refines the velocity model using reflected signals. The velocity model is updated based on the imaging results, creating a closed-loop system that improves image resolution while managing complexity through iterative refinement rather than requiring a perfectly complex initial model.
2Measurement precision
If conventional borehole-only data is used for velocity modeling, then the modeling process is simple, but the accuracy of velocity models deteriorates due to lack of information from offset wells
Solution Approach 1:
The patent merges velocity model construction from multiple data sources including borehole data and offset well data. By combining these different data types and integrating them into a unified velocity model, the system achieves higher accuracy while managing the increased data quantity through systematic integration processes.
Solution Approach 2:
The velocity model serves multiple functions simultaneously: it represents formation properties, guides imaging processes, and incorporates information from various data sources. This multi-functionality allows the system to handle the increased complexity of using multiple data sources while maintaining coherent and accurate velocity modeling.
3Measurement precision
If static velocity models are used, then the processing time is short, but the imaging accuracy of structures away from borehole deteriorates
Solution Approach 1:
The patent performs preliminary actions by establishing initial velocity models and processing frameworks before the iterative imaging process begins. This allows the system to prepare necessary computational structures and initial conditions, reducing the time required for subsequent iterative refinements while maintaining high imaging accuracy.
Solution Approach 2:
The imaging process maintains continuous useful action through iterative refinements where each iteration builds upon the previous one. Rather than requiring complete reprocessing, the system continuously refines the velocity model and images, maintaining productivity while improving accuracy through incremental updates.
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 provides high-resolution images of geological structures, enabling better drilling and completion strategies by accurately modeling velocity and imaging structures that may not intersect the borehole, improving the precision of reservoir boundary visualization and geomechanical property estimation.
Implementation Method 1
Borehole sonic logging tools have sound transmitters and receivers that are primarily designed to record signals with which to estimate formation velocity along the borehole, for both compressional (P-wave) and shear wave (S-wave) arrivals
Implementation Method 2
reflected signals bouncing off (reflecting from) formation changes (interfaces) located at a distance from the borehole may be recorded
Data Source
AI summary
Systems and methods for forming sonic images of a subterranean region and disclosed. The method may include acquiring, using a borehole sonic tool, a full-waveform sonic dataset pertaining to a borehole penetrating the subterranean region receiving the full-waveform sonic dataset, obtaining a sonic velocity model pertaining to the subterranean region, and obtaining a trajectory for the borehole, wherein the trajectory characterizes a spatial path of the borehole through the subterranean region in a first coordinate system, and transforming the sonic velocity model from the first coordinate system into a second coordinate system. The method further includes forming a sonic image in the second coordinate system from the sonic velocity model in the second coordinate system and the full-waveform sonic dataset, transforming the sonic image from the second coordinate system into the first coordinate system; and identifying a location of a sonic reflector within the sonic image.