Sidewall Core Depth Verification via Calibrated Borehole Image Logs
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Solution Overview
Problem
The determination of the depth of sidewall core samples in boreholes is prone to errors due to wireline cable stretching and friction, making manual determination difficult, time-consuming, and expensive, necessitating an automated process.
Innovation Solution
A method involving the generation of a calibrated borehole image log by correlating a reference log with a borehole image log, identifying candidate sidewall core image artifacts, and assigning confidence values to determine the probability of the sidewall core sample depth using cross-correlation and dynamic warping techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual determination of sidewall core sample depth is used, then depth measurement can be obtained, but the process is difficult, prone to error, time-consuming and expensive
Solution Approach 1:
The patent replaces manual mechanical depth determination with an automated computer-based system that uses image processing and pattern recognition algorithms to automatically identify sidewall core sample locations and calculate their depths, eliminating manual labor and associated errors
Solution Approach 2:
The system creates a digital copy (borehole image log) of the physical borehole environment and uses this copy to automatically determine sample depths through computational analysis, avoiding the need for direct manual measurement in the challenging borehole environment
2Measurement precision
If wireline cable is used for depth measurement, then depth data can be obtained, but cable stretching and friction cause depth errors
Solution Approach 1:
The patent introduces borehole image logs as an intermediary reference that indirectly determines sample depths by matching image features with logged depth information, bypassing the unreliable direct cable-based measurement system
Solution Approach 2:
The system uses cross-correlation analysis to compare the borehole image log with the reference log, automatically detecting depth shifts and friction effects, then applies corrections based on this feedback to improve measurement accuracy
3Productivity
If automated process is implemented, then time consumption and cost are reduced, but system complexity increases
Solution Approach 1:
The patent implements a multi-functional computer-based system that performs multiple tasks including image processing, pattern recognition, depth calculation, and error correction within a single integrated platform, improving productivity while managing complexity through consolidation
Solution Approach 2:
The system uses self-contained algorithms for automatic feature detection and depth determination without requiring external manual intervention, enabling automated processing that improves efficiency while the standardized algorithms keep complexity manageable
Data Source
AI summary
A method of determining the depth of a sidewall core sample taken from a borehole relative to a reference log of the borehole. The method includes obtaining a reference log recorded on a reference log depth scale and a borehole image log recorded on a borehole image log depth scale of a portion of the borehole from which the sidewall core sample has been taken. The method further includes generating a calibrated borehole image log from the borehole image log and the reference log and identifying a candidate sidewall core image artifact in the calibrated borehole image log. The method also includes assigning a confidence value for the candidate sidewall core image artifact based on a characteristic of the candidate sidewall core image artifact, and determining, using the confidence value, a probability that the sidewall core sample was collected at a certain depth on the reference log depth scale.