Stage Tool Isolation Assembly Preventing Cement Ingress

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Solution Overview

Problem

Current hydraulic stage tool technology results in undesired cement entering the tubular below the stage tool, requiring cleanout or drilling runs, increasing costs, and potentially fouling open-hole pump-down tools.

Innovation Solution

A stage tool with an isolation assembly that includes one or more one-way valves, which allow flow in the downhole direction while preventing cement ingress into the tubular below the isolation assembly, thereby minimizing the risk of cement entering the lower portion of the tubular.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If current hydraulic stage tool technology is used, then cementing of the tubular in the wellbore above the open-hole completion is enabled, but undesired cement enters the tubular below the stage tool requiring cleanout or drilling runs

Engineering Contradiction:

Improveprevention of cement ingressVSAvoidneed for cleanout operations

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

A flow restrictor is installed as an intermediary component within the stage tool assembly to control and restrict cement flow. The flow restrictor creates a pressure differential that prevents cement from entering the tubular below the stage tool while still allowing completion fluids to pass through during installation and circulation operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the flow parameters by introducing a flow restrictor that creates a pressure differential across a specific location in the tubular. This pressure differential parameter change prevents cement ingress while maintaining fluid flow capability for other operations.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If float-in subs using frangible discs are used to assist with installation, then the portion above the float-in sub can be filled with higher density fluid, but the cost is substantial and debris can foul open-hole pump-down tools

Engineering Contradiction:

Improveinstallation assistanceVSAvoiddebris fouling

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The flow restrictor is designed as a disposable component that is installed temporarily during the cementing operation and then removed or left in place without causing harm. It performs its isolation function during cementing and is subsequently discarded, avoiding the debris fouling problem associated with frangible discs while providing the needed installation assistance.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If one-way valves are used to prevent cement ingress, then cement entry is minimized, but the valve must be held closed during cementing operation requiring biasing devices or pressure management

Engineering Contradiction:

Improvecement flow preventionVSAvoidvalve control mechanism

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The flow restrictor is designed to automatically maintain the pressure differential needed to prevent cement ingress without requiring external biasing devices or complex control mechanisms. The restrictor itself generates and maintains the pressure differential through its flow resistance characteristics, making the system self-regulating and simpler in design.

Inventive Principle:

Principle #25Self-service

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 use of one-way valves in the stage tool effectively prevents or minimizes cement ingress into the lower tubular, reducing the need for cleanouts and maintaining the functionality of open-hole pump-down tools.

Implementation Method 1

Increasing the differential pressure across the closed-deactivated one-way valve causes the one-way valve to move to an activated position. When in the closed position, the one-way valve seals to prevent flow in an uphole direction.

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

The isolation assembly prevents or minimizes cement entering the lower portion of the tubular below the isolation assembly while allowing flow of liquid and passage of pump-down tools in a downhole direction.

Methodology Applied

Scientific EffectFlow restriction: Pressure Gradient

Data Source

PatentUS12264553B2Stage tools, stage tool assemblies, cementing operations, and related methods of use

Publication Date: 2025.04.01 2458584 ALBERTA LTD

AI summary

A stage tool assembly has a tubular body defining an interior bore with a port; an opening sleeve axially movable from a first position that restricts the port to a second position that exposes the port; a closing sleeve axially movable from a first position that exposes the port to a second position that restricts the port; and an isolation assembly downhole of the port that, at least when in an activated mode: permits tool passage in a downhole direction through the interior bore; and restricts flow through the interior bore.