Wireline Cable Creep Modeling for Real-Time Depth Prediction
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Solution Overview
Problem
Current methods for estimating and controlling the depth of wireline cables are inaccurate due to complex job conditions, including extended depth, tool configuration variations, and cable creep, which is influenced by factors like toolstring momentum, wave propagation, and wellbore fluid viscosity, making real-time operations challenging.
Innovation Solution
A one-dimensional constitutive model using linear viscoelasticity and the Voigt-Wiechert model, combined with a Prony series, is developed to predict time- and temperature-dependent elongation of wireline cables, calibrated with creep tests and verified in ABAQUS, enabling real-time depth control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional depth estimation methods (depth wheel or encoder) are used, then the measurement process is simple, but the measurement precision deteriorates under complex job conditions including cable creep
Solution Approach 1:
The patent transforms the physical cable creep problem into a mathematical parameter prediction problem by using constitutive models (Kelvin chain model, Prony series) that describe time-dependent elongation behavior. The system predicts depth based on time, temperature, and load parameters rather than direct mechanical measurement, achieving high precision without complex hardware modifications
Solution Approach 2:
The patent replaces traditional mechanical depth measurement systems (depth wheels, encoders) with a computational prediction system based on viscoelastic constitutive models. This substitution eliminates the need for complex mechanical measurement devices while achieving superior accuracy by modeling the cable's time-dependent mechanical behavior
2Measurement precision
If direct downhole measurement of tool movement is used, then the measurement precision improves, but the productivity deteriorates due to time consumption
Solution Approach 1:
The patent performs preliminary characterization of cable creep behavior through constitutive modeling and parameter identification before actual wireline operations. By pre-determining the viscoelastic properties and creep characteristics of the cable, the system enables real-time depth prediction during operations without requiring time-consuming direct measurements, thus maintaining both high precision and productivity
Solution Approach 2:
The patent creates a virtual model (constitutive model) that replicates the physical cable's creep behavior. This digital twin allows real-time prediction of cable elongation and tool depth without requiring physical measurement devices downhole, achieving both measurement precision and real-time operation efficiency
3Manufacturing precision
If complex constitutive models are used to predict cable elongation, then the manufacturing precision improves, but the device complexity increases
Solution Approach 1:
The patent segments the complex viscoelastic creep behavior into distinct components using the Kelvin chain model with multiple elements in series. Each element represents a specific relaxation mechanism, allowing the complex deformation behavior to be broken down into manageable segments that can be individually calibrated and computed, achieving high prediction accuracy without excessive complexity
Solution Approach 2:
The patent transforms the complex constitutive model into a computationally efficient form by using the Prony series representation and performing parameter identification through curve fitting. This parameter transformation allows the complex physical model to be implemented with a limited set of measurable parameters, reducing computational complexity while maintaining manufacturing precision
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
The model accurately predicts cable elongation under varying conditions, allowing for efficient real-time estimation and control of cable depth, even in complex environments.
Implementation Method 1
creep of the cable becomes significant to length change of the cable
Implementation Method 2
Elastomers and polymers usually show significant time-dependent viscoelastic and viscoplastic behavior where molecular chains slide past each other under stress
Implementation Method 3
considering tension stretch and thermal expansion of the cable
Data Source
AI summary
A method and system for monitoring cable creep may include using a constitutive model. A method and system for characterizing creep of wireline cables, the method comprising the steps of providing a wireline cable with a gauge section, fixing a first end of the wireline cable, connecting a second end of the wireline cable to a load cell, wherein the load cell applies and controls tension on the wireline cable, attaching an extensometer to the first end and the second end of the wireline cable, wherein the extensometer is used to measure the length change of the gauge section, and recording one or more data of the wireline cables to characterize the creep of the wireline cables.