Pressure-Actuated Section Mill with Sequential Centering

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Solution Overview

Problem

Current methods for cutting and milling larger diameter casing in wellbores are inefficient and costly due to the need for smaller diameter tools to navigate through smaller inner diameters and potential eccentric casing conditions, which hinder centering and prolong the plugging and abandonment process.

Innovation Solution

A section mill with extendable pressure-actuated cutting and centering blades, utilizing a rack and pinion drive system to extend centering blades first, followed by cutting blades, allowing for centering and efficient cutting through the use of a mandrel with a flow restriction mechanism to activate springs for blade extension and retraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a smaller diameter tool is used to navigate through the smallest inner diameter restriction of casing, then the tool can pass through the inner casing, but it cannot efficiently cut and mill the larger diameter casing without removal of the restriction

Engineering Contradiction:

Improveability to navigate through inner casingVSAvoidefficiency of cutting and milling larger casing

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The cutting tool employs extendable cutting blades that can be deployed after navigating through the inner casing. The blades are initially retracted to allow passage through the smallest inner diameter restriction, then extended via hydraulic actuation to efficiently cut and mill the larger diameter casing, thus adapting the tool's effective diameter dynamically to different operational phases

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The cutting tool is divided into functional segments including the body, extendable cutting blades, and centering blades. This segmentation allows the tool to navigate through restrictions with blades retracted, then deploy blade segments to perform cutting operations on larger casing, enabling multi-stage functionality within a single tool

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If the inner and outer casing are not concentric, then the cutter must go through the smaller inner casing and exit through a cut section, but this prolongs the process and increases cost

Engineering Contradiction:

Improveability to handle eccentric casing conditionsVSAvoidtime required for plugging and abandonment

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The tool employs centering blades as an intermediary mechanism that deploy after navigation through inner casing. These centering blades adjust the tool's position within the outer casing to achieve proper centering, enabling efficient cutting operations even when inner and outer casing are eccentric, thus eliminating the need to exit through cut sections

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The tool performs preliminary navigation through the inner casing with blades retracted, then deploys centering blades as a preliminary action before cutting operations. This preliminary centering action prepares the tool for efficient cutting of the larger casing, preventing the need for time-consuming corrective operations later

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If conventional cutters are used, then they can cut the innermost section of casing, but they cannot cut larger diameter casing lower in the well bore without removal of the restriction

Engineering Contradiction:

Improvesimplicity of cutter designVSAvoidability to cut tubulars of various diameters

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The cutting tool is designed as a universal device that can cut tubulars of various diameters. It features extendable cutting blades that can be deployed to match the diameter of different casing sections, allowing a single tool design to perform multiple cutting functions throughout the wellbore without requiring removal of inner casing restrictions

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

Enables efficient cutting and milling of tubulars of various diameters, reducing time and expense by ensuring proper centering and cutting through larger casing sections without the need for removal of inner diameter restrictions, thus facilitating faster and more cost-effective plugging and abandonment operations.

Implementation Method 1

Applied pressure results in flow through a flow restriction that creates a force on return springs associated with the centering and the cutting blades

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

The blades are extended or retracted with a rack and pinion drive system

Methodology Applied

Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentUS9187971B2Oilfield downhole wellbore section mill

Publication Date: 2015.11.17 BAKER HUGHES CO

AI summary

A section mill features extendable cutting blades and centering blades that are pressure actuated for sequential extension of the centering blades before the cutting blades. Applied pressure results in flow through a flow restriction that creates a force on return springs associated with the centering and the cutting blades. The springs allow extension of the centering blades before the cutting blades. Another spring returns a mandrel to the run in position on cessation of flow. The blades are extended or retracted with a rack and pinion drive system.