Pulse Generating Device Frequency Adjustment for Drill String Vibration

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Solution Overview

Problem

The increasing length of horizontal wellbores in oil and gas operations leads to significant friction and potential sticking of drill strings, which can be exacerbated by the use of multiple downhole pulse generating devices causing sympathetic vibrations that may damage the drill string.

Innovation Solution

The method involves predicting and minimizing sympathetic vibrations by adjusting the frequency of pulse generating devices to differ from the natural frequency of the drill string and optimizing the placement of these devices to ensure that the energy introduced into the system is less than the energy dissipated, thereby reducing the risk of damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If multiple pulse generating devices are coupled to the drill string to minimize friction, then the drill string can maintain movement and prevent sticking, but sympathetic vibrations occur that can damage the drill string

Engineering Contradiction:

Improvedrill string movementVSAvoidsympathetic vibrations

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by adjusting the operating frequency of pulse generating devices to differ from the natural frequency of the drill string. This frequency parameter adjustment prevents resonant sympathetic vibrations while maintaining the friction-reducing vibration benefits, thus resolving the contradiction between enabling drill string movement and preventing vibration-induced damage

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by using multiple pulse generating devices that can operate independently at different frequencies or phases. This dynamic configuration allows the system to maintain drill string movement through vibrations while avoiding fixed-frequency sympathetic resonance that would cause damage

Inventive Principle:

Principle #15Dynamics

2Productivity

If the length of the horizontal wellbore increases to increase interface with producing formation, then productivity increases, but friction and sticking force on drill string increases

Engineering Contradiction:

Improveinterface with producing formationVSAvoidfriction force

Core Design Contradiction:

ProductivityVSForce

Solution Approach 1:

The patent applies segmentation by dividing the drill string into multiple sections with pulse generating devices distributed along its length. This segmentation allows vibrations to be applied at multiple points simultaneously, effectively counteracting the increased friction force resulting from longer horizontal wellbores and greater drill string-formation interface

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements periodic action through pulse generating devices that create rhythmic vibrations in the drill string. These periodic vibrations maintain drill string movement by preventing static friction buildup, enabling the system to handle longer horizontal wellbores with increased friction while maintaining productivity

Inventive Principle:

Principle #19Periodic action

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 effectively minimizes the risk of drill string damage by preventing sympathetic vibrations and ensuring a balanced energy distribution, allowing for safer and more efficient drilling operations.

Implementation Method 1

create fluctuations in fluid pressure that result in vibrating the drill string

Methodology Applied

Scientific EffectPressure fluctuations:

Implementation Method 2

The vibrations help maintain movement of the drill string

Methodology Applied

Scientific EffectVibration: Vibration

Implementation Method 3

multiple pulse generating devices can result in sympathetic vibration assumed by the drill string

Methodology Applied

Scientific EffectSympathetic vibration: Resonance

Data Source

PatentUS11339642B2Predicting damage to wellbore tubulars due to multiple pulse generating devices

Publication Date: 2022.05.24 LANDMARK GRAPHICS CORP

AI summary

A method includes comparing a natural frequency of a tubular with a frequency of each of at least two pulse generating devices positioned adjacent each other on the tubular, the tubular and the at least two pulse generating devices comprising an energy system; adjusting the frequency of at least one of the at least two pulse generating devices when the frequency is equal to the natural frequency of the tubular and obtaining an adjusted frequency different from the natural frequency; calculating an energy distribution in the energy system based on the natural frequency and the adjusted frequency of the at least one of the at least two pulse generating devices; and determining a new location on the tubular for positioning one or more of the at least two pulse generating devices such that energy introduced into the energy system is less than energy dissipated from the energy system.