Wellbore String Friction Analysis Using Derivative Comparison

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Solution Overview

Problem

Current well operations in the oil and gas industry face challenges due to torque and drag forces resulting from friction, as existing modeling tools can only estimate average friction factors along the wellbore, failing to provide accurate local friction factor measurements at specific locations, which hinders efficient movement of string assemblies and increases the risk of equipment failure.

Innovation Solution

A method is developed to calculate local friction factors by obtaining surface data, modeling parameters over a range of depths for various friction factors, calculating and comparing derivatives of surface and modeled data to determine local friction factors, and adjusting operating parameters accordingly, allowing for precise adjustments to mitigate friction-related issues during well operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If average friction factors are used for modeling, then the modeling process is simple, but the accuracy of local friction assessment is poor

Engineering Contradiction:
Improvelocal friction factor accuracyVSAvoidmodeling complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The wellbore is divided into multiple depth segments, and friction factors are calculated independently for each segment rather than using a single average value. This segmentation allows local friction variations to be captured while maintaining a systematic modeling approach that balances complexity and accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The methodology transitions from one-dimensional average friction modeling to a depth-resolved multi-dimensional friction profile. By introducing the depth dimension into friction factor calculation, the model captures spatial variations in friction conditions along the wellbore, significantly improving local assessment accuracy.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If local friction factors are calculated using derivative comparison, then friction hotspots are accurately identified, but the calculation complexity increases

Engineering Contradiction:
Improvefriction factor resolutionVSAvoidcalculation efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

Modeled data is pre-calculated for a range of assumed friction factors before comparing with surface data. This preliminary modeling step creates a reference framework that accelerates the iterative optimization process, allowing rapid identification of local friction factors without repeated complex simulations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The methodology replaces direct physical measurement of local friction with a computational approach using derivative comparison of surface data. This substitution transforms a potentially complex physical measurement problem into a more efficient mathematical optimization problem that can be solved using surface-level observations.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If real-time adjustments are made based on local friction factors, then equipment failure risk is reduced, but the operational complexity increases

Engineering Contradiction:
Improveequipment safetyVSAvoidoperational simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system continuously monitors surface data, compares it with modeled data, and adjusts operating parameters based on identified local friction factors. This closed-loop feedback mechanism enables real-time adaptation to changing friction conditions, improving equipment safety while automating the complexity of decision-making.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The methodology enables the drilling system to self-adjust operating parameters based on real-time friction assessment without requiring constant operator intervention. The automated identification of friction hotspots and recommended parameter adjustments allows the system to manage its own operational risks, improving safety while reducing operational burden.

Inventive Principle:
Principle #25Self-service

Data Source

PatentUS11365608B2Method of operating a tubular string assembly within a wellbore
Publication Date: 2022.06.21 EXXONMOBIL UPSTREAM RESEARCH COMPANY(US)
  • US11365608B2 patent drawing
  • US11365608B2 patent drawing
  • US11365608B2 patent drawing

AI summary

A method of moving a string assembly within a wellbore is disclosed. In some embodiments, the method comprises moving the string assembly within the wellbore; obtaining surface data regarding at least one parameter associated with moving the string assembly within the wellbore over a range of depths; modeling the at least one parameter over the range of depths for a plurality of assumed friction factors to obtain modeled data for each assumed friction factor; calculating a derivative of the surface data over the range of depths; calculating a derivative of the modeled data over the range of depths; comparing the derivative of the surface data to the derivative of the modeled data; determining one or more local friction factors for the range of depths based on the comparison; and adjusting at least one string assembly operating parameter based on the one or more local friction factors.