Well Bore Friction Measurement via Cyclic Hook Load Analysis
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Solution Overview
Problem
Current methods for identifying forces on tubular members within a well bore, such as casing strings, are unable to accurately measure static friction and viscous drag, leading to issues like stuck pipes and potential well bore damage from downhole pressure waves.
Innovation Solution
A system that measures and processes load values during multiple cycles of a tubular member's movement within the well bore, identifying friction and viscous drag forces by analyzing load variations, trends, and oscillations to predict the likelihood of sticking and adjust movement accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional steady-state hook load measurement is used, then the measurement process is simple, but the measurement precision of static friction and viscous drag is insufficient
Solution Approach 1:
The patent segments the continuous lowering process into multiple discrete cycles, each comprising distinct phases (acceleration, constant speed, deceleration). By analyzing hook load data separately for each phase and cycle, the system can isolate and measure static friction (during phase transitions) and viscous drag (during constant speed motion) with higher precision, rather than treating the entire process as a single steady-state measurement.
Solution Approach 2:
The system performs preliminary data processing by identifying and separating different motion phases before calculating friction forces. Load values are pre-processed to distinguish between acceleration, constant velocity, and deceleration phases, enabling accurate differentiation between static and dynamic friction components before final friction calculation occurs.
2Measurement precision
If multiple load values are measured and analyzed during each cycle, then the identification accuracy of friction forces improves, but the loss of time for data processing increases
Solution Approach 1:
The patent implements periodic measurement and analysis cycles, where hook load data is collected at multiple points during each lowering cycle and processed systematically. By establishing a repeating pattern of measurement phases (acceleration, constant speed, deceleration) and analyzing data at regular intervals within each cycle, the system achieves comprehensive friction characterization without requiring continuous real-time processing of every data point.
Solution Approach 2:
The system measures more load values than strictly necessary for basic friction calculation by including multiple measurement points within each motion phase. This excessive measurement approach ensures capture of all relevant friction characteristics (static and dynamic) even when optimal measurement timing varies, while processing only the essential phase-transition points rather than all collected data points.
3Productivity
If the tubular member is moved quickly through the well bore, then the productivity increases, but the risk of stuck pipe and well bore damage increases
Solution Approach 1:
The system continuously monitors hook load values during the lowering process and compares them against calculated friction thresholds and historical data. When measured loads approach or exceed predicted static friction values (indicating potential sticking conditions) or when viscous drag exceeds safe limits (indicating excessive speed), the system provides feedback to operators to adjust movement speed or take corrective action, enabling high-speed operation while maintaining safety margins.
4Reliability
If the tubular member is moved slowly to avoid stuck pipe, then the reliability improves, but the productivity decreases
Solution Approach 1:
The patent implements dynamic speed adjustment based on real-time friction monitoring. Rather than maintaining a constant slow speed, the system allows the tubular member to be moved at varying speeds - faster when friction levels are low and safe, slower when approaching friction thresholds. This dynamic approach optimizes both productivity and reliability by adapting movement speed to actual downhole conditions rather than using fixed conservative limits.
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 accurate identification of static friction and viscous drag forces, reducing the risk of stuck pipes and minimizing well bore damage by providing real-time data for operational adjustments.
Implementation Method 1
the rig comprises a measurement unit arranged to measure a force imparted by the member onto the moveable unit
Implementation Method 2
determine second data indicative of the friction between the well bore and the member from the identified plurality of load values
Implementation Method 3
viscous drag caused by displaced fluid
Data Source
AI summary
A member is moved within a well bore in a plurality of cycles, each cycle including holding the member in slips, releasing the slips, moving the member within the well bore and applying the slips. The hook load is measured at multiple points during each of these cycles and the plurality of measured values are used to identify data indicative of the forces on the member within the well bore.