Toe Circulation Sub with Straight Bore and Ball Retainer

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Solution Overview

Problem

Traditional toe circulation subs in wellbore liners are prone to clogging due to their torturous path, which can lead to plugging and interference with intervention tools, and once closed, they cannot be reopened.

Innovation Solution

A toe circulation sub with a straight flow path and a ball seat mechanism that allows fluid circulation until a ball is released to seal the path, preventing backflow and interference, and includes a ball retainer to maintain the seal without obstructing further operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a torturous flow path is used in the toe sub, then fluid circulation is achieved, but the device is prone to clogging and reliability deteriorates

Engineering Contradiction:

Improveresistance to cloggingVSAvoidflow path configuration

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of using a torturous flow path to achieve circulation, the patent inverts the approach by using a straight, simple flow path that is resistant to clogging. The circulation function is achieved through the simplicity of the path rather than complexity, eliminating bends and corners that trap debris.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent employs curved or spheroidal flow paths within the toe sub that allow fluid to circulate smoothly without sharp angles or dead zones. The curved geometry prevents debris accumulation while maintaining effective circulation, resolving the contradiction between circulation capability and clogging resistance.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Reliability

If the toe sub is closed by a ball seat mechanism, then flow path is sealed, but the ball can roll back and interfere with intervention tools

Engineering Contradiction:

Improvesealing capabilityVSAvoidball interference with tools

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the ball from the liner after it has served its sealing purpose. The ball is launched to close the toe sub, but then a retrieval mechanism is activated to pull the ball back into the toe sub body, removing it from the liner where it could interfere with intervention tools while maintaining the seal.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a retrieval mechanism as an intermediary between the ball and the liner. This mechanism captures and retrieves the ball after sealing, preventing direct interference with intervention tools while preserving the sealing function. The intermediary resolves the conflict between sealing reliability and tool accessibility.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If the flow path is permanently closed, then pressure isolation is achieved, but the sub cannot be reopened for further operations

Engineering Contradiction:

Improvepressure isolationVSAvoidreopenability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent transforms the permanently closed toe sub into a dynamically controllable device. A retrieval mechanism allows the system to switch between open and closed states as needed. The toe sub can be closed for pressure isolation when required, then reopened by retrieving and relaunching the ball, providing adaptability for multiple operations.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements a recoverable sealing system where the ball is retrieved after serving its sealing purpose. The ball can be pulled back into the toe sub, allowing the flow path to be reopened for subsequent operations. This recovering mechanism provides both pressure isolation when needed and reopenability for versatility.

Inventive Principle:

Principle #34Discarding and recovering

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 design prevents clogging and allows for controlled fluid flow and pressure isolation, ensuring the liner can be advanced without getting stuck and avoids interference from the ball during operations.

Implementation Method 1

a ball seat in the bore formed to stop and seal with a ball to plug flow through the bore to close the toe circulation sub

Methodology Applied

Scientific EffectSealing:

Implementation Method 2

The piston is pushed down by the applied pressure. Once the piston moves down the flow path is closed from the liner to the openhole

Methodology Applied

Scientific EffectPressure: Pressure Increase

Data Source

PatentUS9920591B2Toe circulation sub

Publication Date: 2018.03.20 PACKERS PLUS ENERGY SERVICES INC

AI summary

A toe circulation sub for a wellbore liner, the toe circulation sub comprising: a body including a connection for connecting the body to a wellbore liner to define an inner facing portion open to an inner diameter of the liner and an outer facing portion open to an outer surface of the liner; a bore through the body from the inner facing portion to the outer facing portion; and, a ball seat in the bore formed to stop and seal with a ball to plug flow through the bore to close the toe circulation sub. The toe circulation sub is useful for methods and may be installed in a wellbore liner.