Multi-Channel Tool String for Well Cleaning and Sealing

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Solution Overview

Problem

Conventional well cleaning methods, such as flushing and reverse circulation, are inefficient, especially in horizontal wells with low pressure or weak formations, and fail to effectively seal leaking wells.

Innovation Solution

A multi-channel tool string with a guide device and adapter system that allows for internal circulation and pressure testing, enabling efficient fluid flow and particle removal, and includes a mechanism for sealing the well using an extension pipe or injected materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If fluid is pumped down through the tool string with return in the annulus, then particles are transported out of the well, but the cleaning efficiency is low due to low fluid velocity in the annulus

Engineering Contradiction:

Improvecleaning efficiencyVSAvoidfluid velocity

Core Design Contradiction:

ProductivityVSSpeed

Solution Approach 1:

The tool string is divided into multiple channels (first channel for supply, second channel for return) to enable separate flow paths. This segmentation allows the return fluid to be directed through the tool string interior rather than relying on the annulus, thereby increasing fluid velocity and cleaning efficiency while maintaining particle transport capability.

Inventive Principle:

Principle #1Segmentation

2Productivity

If fluid velocity in the annulus is increased to improve cleaning efficiency, then particle transport improves, but pressure loss increases causing fluid loss or well control situations

Engineering Contradiction:

Improvecleaning efficiencyVSAvoidpressure loss

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The tool string acts as an intermediary conduit, providing a controlled internal passage for fluid return. This mediator structure allows high-velocity flow with adequate pressure control by directing fluid through the tool string's internal channels rather than the uncontrolled annular space, preventing both fluid loss and well control issues while maintaining cleaning efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If reverse circulation is used to transport particles quickly to the surface, then particle removal efficiency improves, but the flushing effect in the bottom of the well is low due to pressure limitations

Engineering Contradiction:

Improveparticle removal efficiencyVSAvoidflushing effect

Core Design Contradiction:

ProductivityVSForce

Solution Approach 1:

The system merges the advantages of both conventional and reverse circulation by combining a supply channel and return channel within the tool string. Fluid is supplied through the first channel and returns through the second channel, creating both downward flushing action (improving bottom-hole cleaning) and upward particle transport (improving removal efficiency), thereby combining the benefits of both methods.

Inventive Principle:

Principle #5Merging (Combining)

4Productivity

If a double string is used for cleaning horizontal wells, then cleaning efficiency improves, but the device complexity increases and is restricted to shallow wells with specific pressure ratios

Engineering Contradiction:

Improvecleaning efficiencyVSAvoidstring complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The tool string is designed with multi-functional capability, serving both as a supply line and return line through its multiple channels. This universal design allows the same tool string structure to handle both fluid supply and particle-laden fluid return, eliminating the need for separate double-string configurations and enabling application in deeper wells beyond the restrictions of conventional double-string systems.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Improves well cleaning efficiency, enhances pressure control, and allows for effective sealing of wells, reducing fluid loss and reinforcing the well formation during drilling operations.

Implementation Method 1

fluids and particles from the well are transported back to the surface through at least one other of the channels in the string

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

a guide device at the second end of the tool string... arranged to lead into the well

Methodology Applied

Scientific EffectFluid flow direction control:

Implementation Method 3

At least one of the channels in the tool string is pressure tested during run-in and/or after it is run into the well

Methodology Applied

Scientific EffectPressure testing:

Data Source

PatentUS8276668B2Method and device for cleaning and sealing a well

Publication Date: 2012.10.02 REELWELL AS

AI summary

The present invention relates to a method for cleaning and possibly sealing a subsurface well. According to the method a multichannel tool string comprising an adapter on a first end of the tool string, a guide device at the second end of the tool string are run into the well, whereupon the guide device is activated in order to permit the well to be flushed by the supply of fluid through at least one of the channels in connection with the tool string and fluids and particles from the well are transported back to the surface through at least one other of the channels in connection with the tool string. The invention also relates to a device for cleaning and possibly sealing a subsurface well.