Downhole Tool Positioning Using Casing Collar Feedback
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Solution Overview
Problem
Existing methods for determining the depth of downhole conveyance lines in wells are inefficient and imprecise, often requiring significant delays for calibration due to thermal expansion, kinking, and elasticity, leading to inaccuracies in tool location, especially in deep and complex wells.
Innovation Solution
A method utilizing a locator tool to detect well features and combine this information with conveyance line characteristics in a closed-loop manner, employing real-time machine learning to estimate depth without prolonged pauses, using multiple passes and fusion processing to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional reel deployment metering is used to estimate conveyance depth, then the measurement process is simple, but the depth determination accuracy deteriorates significantly (off by 3-9 feet or more in deep wells)
Solution Approach 1:
The patent introduces an intermediary calibration process using known downhole features (casing collars) as reference points. The locator tool detects these features and compares their detected positions with their known depths, calculating calibration factors that account for line elasticity, thermal expansion, and kinking. This intermediary reference system mediates between the simple reel metering and the actual tool position, significantly improving depth determination accuracy without requiring complex direct measurement equipment.
Solution Approach 2:
The patent replaces the purely mechanical reel deployment metering system with a hybrid system that incorporates electronic detection (locator tool detecting casing collars), data processing (comparing detected positions with known depths), and computational correction (calculating calibration factors). This substitution of mechanical measurement with electronic sensing and computational analysis resolves the accuracy problem while managing complexity through software-based solutions.
2Measurement precision
If calibration is performed by dropping and withdrawing the conveyance line with pauses at each casing collar, then depth calibration accuracy is improved, but operational time increases significantly (delays of a day or more)
Solution Approach 1:
The patent enables continuous depth estimation and calibration during normal conveyance line deployment or withdrawal operations. The locator tool continuously detects casing collars and the system continuously calculates depth information and calibration factors without requiring pauses in operations. This transforms the calibration process from a discrete, time-consuming procedure into a continuous process that occurs alongside normal operations, eliminating delays of a day or more while maintaining high accuracy.
Solution Approach 2:
The system performs self-calibration by automatically detecting casing collars, comparing their positions with known depths, and adjusting calibration factors without requiring external intervention or separate calibration operations. The calibration process becomes an integrated, automated function that occurs during normal operations, eliminating the need for dedicated calibration time and personnel intervention.
3Length of stationary object
If the conveyance line is used to reach extensive depths (10,000 to 20,000 feet or more), then the ability to access deep well locations is improved, but depth determination accuracy deteriorates due to growing load, elasticity, thermal expansion, and kinking
Solution Approach 1:
The patent implements a feedback mechanism where the locator tool continuously detects known downhole features (casing collars) and the system compares detected positions with their known depths. This feedback loop provides real-time information about line elasticity, thermal expansion, and kinking effects, allowing the system to calculate and apply calibration factors that compensate for these phenomena. The feedback enables accurate depth determination even when the conveyance line reaches extensive depths of 10,000 to 20,000 feet or more.
Solution Approach 2:
The patent accounts for parameter changes in the conveyance line by detecting and measuring effects such as elasticity-induced stretch, thermal expansion, and kinking-induced length variations. The system calculates calibration factors that adjust for these parameter changes based on detected casing collar positions, enabling accurate depth determination despite the line's physical changes under various conditions during deployment to extreme depths.
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
Enables rapid and accurate depth estimation and conveyance line condition assessment, reducing operational delays from days to minutes, and ensuring precise tool placement for interventions.
Implementation Method 1
be prone to some degree of thermal expansion
Implementation Method 2
a natural elasticity
Data Source
AI summary
Systems and techniques for establishing tool location in a well and conveyance line characteristics of a conveyance line accommodating the tool. The systems and techniques are directed at a closed loop manner of acquiring well location information. Thus, multiple pass detections of a well feature may be utilized to map, update and/or provide well location information in addition to conveyance line characteristic information in real-time. This may occur in absence of prior stored well mapping information or with supplemental information thereof.