Drill Pipe Compression Correction for Milling Operations
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Solution Overview
Problem
Current downhole operations, such as milling casing exits in a borehole, face challenges in accurately controlling and measuring penetration rates due to drill pipe compression and frictional forces, which can lead to incomplete milling and increased costs.
Innovation Solution
A control system that measures and corrects for drill pipe compression by recording surface weight-on-bit and block movements, allowing for accurate determination of actual displacement and penetration rates, eliminating the need for downhole telemetry technology when an absolute bottomhole reference is available.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If downhole operations are controlled using traditional methods without compression correction, then the control system is simpler, but the measurement precision of penetration rates deteriorates due to drill pipe compression and frictional forces
Solution Approach 1:
The control system continuously monitors weight-on-bit measurements and block height positions, compares actual displacement against expected displacement, and automatically applies compression corrections to penetration rate calculations. This closed-loop feedback mechanism ensures accurate penetration measurements while accounting for drill pipe compression and frictional forces without requiring complex downhole telemetry equipment.
Solution Approach 2:
The patent replaces complex downhole mechanical measurement systems with surface-based electronic sensors and computational algorithms. By using weight-on-bit cells and block height position sensors combined with computer-based compression correction calculations, the system achieves equivalent or superior measurement precision without the complexity and cost of downhole telemetry technology.
2Reliability
If compression correction is applied to account for frictional forces, then the reliability of downhole operations improves, but the device complexity increases
Solution Approach 1:
The control system performs preliminary compression characterization by analyzing weight-on-bit measurements and block height positions before and during milling operations. By pre-calculating compression effects and frictional forces based on initial measurements, the system establishes correction factors that are applied throughout the operation, ensuring reliable penetration rate measurements from the start without requiring complex real-time downhole instrumentation.
Solution Approach 2:
The patent introduces computational algorithms and software-based compression correction models as intermediaries between raw sensor measurements and final penetration rate calculations. These computational intermediaries process weight-on-bit and block height data to derive accurate penetration rates, eliminating the need for complex physical downhole measurement devices while maintaining high operational reliability.
3Productivity
If accurate penetration rate measurement is achieved through compression correction, then the productivity of single-trip milling operations improves, but the loss of time for additional trips is increased without correction
Solution Approach 1:
The control system uses real-time feedback from weight-on-bit measurements and block height position sensors to continuously monitor and correct for drill pipe compression during milling operations. This ensures accurate penetration rate measurements that prevent premature termination of milling trips, thereby maximizing the productivity of single-trip operations and eliminating the need for additional trips that would result from inaccurate measurements.
4Measurement precision
If downhole subs are used to measure compression, then the measurement precision improves, but the device complexity and cost increase
Solution Approach 1:
The patent replaces downhole mechanical measurement subs with surface-based electronic sensors and computational algorithms. By using weight-on-bit cells, block height position sensors, and computer-based compression correction models, the system achieves equivalent measurement precision without the complexity, cost, and reliability issues associated with downhole telemetry equipment and subs.
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 enables 100% success rate in single-trip casing milling operations by accurately accounting for compression and frictional forces, reducing the need for additional milling trips and minimizing errors in penetration measurements.
Implementation Method 1
obtain an indication of a first displacement, from a base position, of a first portion of a drill string due to a first force being applied to the first portion of the drill string
Implementation Method 2
Current downhole operations, such as milling casing exits in a borehole, face challenges in accurately controlling and measuring penetration rates due to drill pipe compression and frictional forces
Data Source
AI summary
Methods, apparatus, and systems are provided for correcting, or at least adjusting, for drill pipe compression in a downhole operation in a wellbore. An exemplary method includes obtaining an indication of a first displacement, from a base position, of a first portion of a drill string due to a first force being applied to the first portion of the drill string and a second portion of the drill string being stationary; obtaining an indication of the first force; obtaining an indication of a second displacement, from the base position, of the first portion of the drill string due to a second force being applied to the first portion of the drill string while performing a downhole operation; obtaining an indication of the second force; and determining a displacement of the second portion of the drill string, based on the first displacement, the second displacement, the first force, and the second force.