Adjustable Modulated Agitator for Drilling Friction

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Solution Overview

Problem

Long drill strings in horizontal wellbores experience increased friction due to contact with the wellbore wall and buildup of solid materials, leading to potential sticking and damage from multiple pulse generating devices used to mitigate friction, which can cause sympathetic vibrations.

Innovation Solution

An agitator system with concentric power-sections and a controller to selectively control fluid flow through stator and rotor combinations, generating pressure fluctuations and increasing vibrational frequency to reduce friction and prevent sticking, while avoiding damaging vibrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If multiple pulse generating devices are coupled to the drill string to minimize friction, then the friction reduction effect is improved, but sympathetic vibration is generated which can damage the drill string

Engineering Contradiction:

Improvefriction forceVSAvoidsympathetic vibration

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The drill string is divided into multiple segments, each with its own pulse generating device operating at independently controlled frequencies. This segmentation allows each device to address friction in its local section without contributing to sympathetic vibration of the entire drill string, as the frequencies are tuned to be below the natural frequency threshold that causes resonant damage.

Inventive Principle:

Principle #1Segmentation

2Area of stationary object

If the drill string length is increased to extend the horizontal wellbore, then the interface area with the producing formation is increased, but the friction and sticking force on the drill string increases

Engineering Contradiction:

Improveinterface area with formationVSAvoidfriction force

Core Design Contradiction:

Area of stationary objectVSForce

Solution Approach 1:

Pulse generating devices are installed on the drill string before drilling operations begin. These devices pre-establish a capability to generate vibrations that can be activated when needed to prevent friction buildup and sticking, allowing the drill string to maintain movement throughout the extended horizontal wellbore without becoming stuck due to the increased contact area with the formation.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the vibrational frequency of the agitator is increased to reduce friction, then the effectiveness in preventing sticking is improved, but the risk of causing damaging sympathetic vibrations increases

Engineering Contradiction:

Improvedrill string movement efficiencyVSAvoiddamaging vibrations

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system incorporates frequency sensing capabilities that continuously monitor the vibrational state of the drill string. When the sensed frequency approaches the natural frequency threshold that could cause sympathetic vibration and damage, the control system automatically adjusts the agitator frequency downward. This feedback mechanism allows the system to maintain high productivity through effective friction reduction while preventing damaging vibrations by dynamically adapting to the drill string's resonant characteristics.

Inventive Principle:

Principle #23Feedback

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 system effectively reduces friction and prevents drill string sticking by dynamically adjusting vibrational frequency, enhancing drill string movement and reducing the risk of damage from sympathetic vibrations.

Implementation Method 1

generate pressure fluctuations or pressure pulses in the fluid pressure, which increases the speed of the rotor or rotors, and thus, the vibrational frequency of the agitator

Methodology Applied

Scientific EffectPressure fluctuations:

Implementation Method 2

The vibrations help maintain movement of the drill string, which is desirable during operation since the dynamic friction is substantially less than the static friction force

Methodology Applied

Scientific EffectVibration: Vibration

Implementation Method 3

selectively control a flow of drilling fluid through the at least two concentric power modules

Methodology Applied

Scientific EffectFluid flow:

Data Source

PatentUS11261685B2Adjustable modulated agitator

Publication Date: 2022.03.01 HALLIBURTON ENERGY SERVICES INC

AI summary

This disclosure provides an agitator system that includes an agitator assembly of concentric power-sections, (one power-section inside another power-section both of which comprise stators and rotors). The agitator system includes a controller configured to control a valve assembly of the agitator assembly to selectively open and close the valve assembly to allow fluid to selectively flow between the power-sections of the agitator assembly that generates pressure fluctuations or pressure pluses in the fluid pressure, which increases the speed of the rotor or rotors, and thus, the vibrational frequency of the agitator. The controller can be used to increase the vibrational frequency of the agitator assembly when necessary to prevent the drill string from becoming lodged in a wellbore.