Automated Sonic Imaging for 3D Wellbore Structure Orientation
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Solution Overview
Problem
Current sonic imaging methods using downhole measurements struggle to accurately capture the three-dimensional orientation and location of near wellbore formation structures, resulting in 2D migration images that lack quantitative information and are prone to noise and subjectivity, making them inadequate for subsequent modeling and interpretation workflows.
Innovation Solution
An automated methodology that processes sonic waveform data to identify and parameterize the three-dimensional location and orientation of near wellbore formation structures, using procedures such as Tau-P and Event Localization, and ray tracing inversion with three-dimensional slowness time coherence, to generate detailed 3D models and images of acoustic impedance boundaries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If 2D migration imaging is used to visualize near wellbore structures, then the imaging process is simpler and faster, but the 3D orientation and location information is lost and quantitative information is not provided
Solution Approach 1:
The patent transitions from 2D migration imaging to 3D imaging by adding azimuthal dimension to the imaging process. The system processes waveforms from multiple receivers around the borehole circumference to reconstruct 3D images that preserve both spatial location and orientation information of reflectors, thereby resolving the information loss inherent in 2D methods.
Solution Approach 2:
The patent segments the imaging process into multiple independent components: waveform processing for each receiver, individual reflector detection and parameter estimation, and 3D image reconstruction. This segmentation allows complex 3D imaging to be broken down into manageable steps that can be processed efficiently while maintaining computational speed.
2Reliability
If automated processing is implemented to reduce subjectivity, then interpretation consistency improves, but the complexity of processing algorithms increases
Solution Approach 1:
The patent implements self-service through automated waveform processing where the system automatically detects arrival events, estimates reflector parameters, and generates images without requiring manual interpretation. The automated algorithms process waveforms from multiple receivers and independently determine reflector characteristics, reducing subjectivity while the modular algorithm design manages complexity.
Solution Approach 2:
The patent incorporates feedback mechanisms where the automated processing system continuously refines its results by comparing detected reflector parameters against the original waveform data and adjusting interpretations accordingly. This feedback loop ensures consistent and reliable results while providing transparency into the processing steps.
3Ease of operation
If manual interpretation of 2D images is used, then the process is more flexible and easier to control, but it is time-consuming and subjective
Solution Approach 1:
The patent enables self-service by having the system automatically perform waveform processing, reflector detection, parameter estimation, and image generation. This automation eliminates manual interpretation time while the system maintains flexibility through configurable processing parameters and the ability to handle various wellbore configurations and reflector geometries.
Solution Approach 2:
The patent performs preliminary automated processing to prepare and pre-process the waveform data, automatically detecting arrival events and estimating reflector parameters before any user review. This preliminary action reduces the time required for subsequent user review and allows operators to focus on high-value interpretation tasks rather than basic processing.
4Device complexity
If 2D migration images are produced, then the imaging process is simpler, but quantitative information for modeling is not provided
Solution Approach 1:
The patent adds the azimuthal dimension to imaging, transforming 2D images into 3D representations that preserve quantitative information about reflector orientation, location, and geometry. This dimensional enhancement enables direct use of imaging results for subsurface modeling while maintaining reasonable process complexity through systematic algorithms.
Solution Approach 2:
The patent changes the output parameters from qualitative 2D image features to quantitative 3D parameters including reflector position, orientation, and geometry. The system automatically estimates these parameters from waveform data, providing the quantitative information needed for modeling while managing complexity through standardized parameter estimation algorithms.
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 significantly reduces subjectivity and improves the quality of sonic imaging interpretation by providing quantitative 3D data, enhancing the accuracy and efficiency of subsurface modeling and simulation workflows, and allowing for the creation of precise digital models of formation structures.
Implementation Method 1
an acoustic source (or transmitter) of a downhole sonic tool is operated to emit wavefronts that probe the near wellbore structures by propagating, reflecting, and refracting across these structures
Implementation Method 2
wavefronts that probe the near wellbore structures (e.g., fractures, nearby bed boundaries and faults, etc.) by propagating, reflecting, and refracting across these structures
Implementation Method 3
wavefronts that probe the near wellbore structures (e.g., fractures, nearby bed boundaries and faults, etc.) by propagating, reflecting, and refracting across these structures
Implementation Method 4
The downhole sonic tool also includes an array of acoustic receivers (or sensors) that receive the resulting wavefronts to obtain the sonic waveform data
Implementation Method 5
the waveforms are processed to separate out and filter borehole modes and other interfering signals from the waveform data
Implementation Method 6
ray tracing inversion with three-dimensional slowness time coherence, to generate detailed 3D models and images of acoustic impedance boundaries
Implementation Method 7
ray tracing inversion with three-dimensional slowness time coherence, to generate detailed 3D models and images of acoustic impedance boundaries
Data Source
AI summary
A method is provided for identifying and characterizing structures of interest in a formation traversed by a wellbore, which involves obtaining waveform data associated with received acoustic signals as a function of measured depth in the wellbore. A set of arrival events and corresponding time picks is identified by automatic and/or manual methods that analyze the waveform data. A ray tracing inversion is carried out for each arrival event (and corresponding time pick) over a number of possible raypath types to determine i) two-dimensional reflector positions corresponding to the arrival event for the number of possible raypath types and ii) predicted inclination angles of the reflected wavefield for the number of possible raypath types. The waveform data associated with each time pick (and corresponding arrival event) is processed to determine a three-dimensional slowness-time coherence representations of the waveform data for the number of possible raypath types, which is evaluated to determine azimuth position and orientation of a corresponding reflector, and determine the ray path type of the reflected wavefield. The method outputs a three-dimensional position and/or orientation for at least one reflector, wherein the three-dimensional position of the reflector is based on the two-dimensional position of the reflector determined from the ray tracing inversion and the azimuth position of the reflector determined from the three-dimensional slowness-time coherence representation. The information derived from the method can be conveyed in various displays and plots and structured formats for reservoir understanding and also output for use in reservoir analysis and other applications.