Downhole Assembly Fluidizing Stream Inhibits Packoff

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Solution Overview

Problem

Downhole assemblies face packoff events due to cuttings accumulation in wellbores, leading to increased drilling costs and time, as the cuttings bed forms and can obstruct the motion of the assembly, especially in horizontal or inclined wells and breakout regions.

Innovation Solution

A downhole assembly equipped with an energy-storing structure that generates a motive force to emit a fluidizing stream, which fluidizes the cuttings bed, reducing the axial force required to move the assembly and preventing packoff events by decreasing solid-solid shear stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the downhole assembly is moved within the wellbore, then the drilling operation progresses, but cuttings accumulate and form a cuttings bed that causes packoff events

Engineering Contradiction:

Improvedrilling operation progressVSAvoidpackoff events

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary action by fluidizing the cuttings bed before the downhole assembly encounters packoff conditions. The fluidizing stream is emitted in advance to prevent cuttings accumulation from reaching packoff-critical levels, allowing continuous assembly motion without interruption.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A fluidizing stream acts as an intermediary substance between the downhowe assembly and the cuttings bed. This fluid stream modifies the interaction by reducing solid-solid shear stress, enabling the assembly to move through the wellbore without direct mechanical contact resistance from accumulated cuttings.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If drilling fluid flow rate is increased to prevent cuttings accumulation, then cuttings bed formation is reduced, but energy consumption and operational costs increase

Engineering Contradiction:

Improvecuttings bed formationVSAvoiddrilling fluid energy consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

Instead of increasing drilling fluid flow rate throughout the entire wellbore, the system applies fluidization locally at the cuttings bed interface. The fluidizing stream is directed specifically where cuttings accumulation occurs, providing targeted intervention with minimal additional energy consumption compared to system-wide flow increases.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system changes the physical state of the cuttings bed from a compacted solid structure to a fluidized state by emitting a fluidizing stream. This parameter change in the cuttings bed's physical state reduces resistance to assembly motion without requiring proportional increases in drilling fluid flow rate or energy input.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the downhole assembly diameter is increased to improve drilling capacity, then drilling efficiency increases, but the assembly encounters greater resistance from cuttings accumulation

Engineering Contradiction:

Improvedrilling efficiencyVSAvoidresistance from cuttings bed

Core Design Contradiction:

ProductivityVSForce

Solution Approach 1:

The system replaces direct mechanical interaction between the large-diameter assembly and the cuttings bed with a fluid-mediated interaction. The fluidizing stream substitutes for mechanical force application, using fluid dynamics to reduce solid-solid shear stress and enable assembly motion without proportionally increasing mechanical resistance.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 fluidization of the cuttings bed reduces resistance to the downhole assembly's motion, preventing packoff events and allowing for smoother operation and reduced drilling costs by minimizing the formation of cuttings dunes and accumulation.

Implementation Method 1

an energy-storing structure that defines a charged state and a discharged state and that is configured to generate a motive force by transitioning from the charged state to the discharged state

Methodology Applied

Scientific EffectEnergy storage and release: Accumulator (energy)

Implementation Method 2

emitting the fluidizing stream from the downhole assembly to fluidize a portion of a cuttings bed

Methodology Applied

Scientific EffectFluidization: Fluidisation

Data Source

PatentUS9291018B2Systems and methods to inhibit packoff events during downhole assembly motion within a wellbore

Publication Date: 2016.03.22 EXXONMOBIL UPSTREAM RESEARCH COMPANY(US)

AI summary

Systems and methods to inhibit packoff events during downhole assembly motion within a wellbore comprise a downhole assembly that includes an energy-storing structure that defines a charged state and a discharged state and is configured to generate a motive force upon transitioning from the charged state to the discharged state. A fluidizing stream is generated with the motive force from the energy-storing structure which emits the fluidizing stream from the downhole assembly to fluidize a portion of a cuttings bed that may be within the wellbore and proximal to the downhole assembly.