Eccentric Plug for Downhole Tool Actuation

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Solution Overview

Problem

In oil and gas well tubulars, the inner diameter of seats decreases as you move down the tubular, causing issues with plug elements passing through and restricting fluid flow consistently.

Innovation Solution

Eccentrically-shaped plug members that maintain a consistent inner diameter across multiple seats, allowing them to pass through upper seats and land on lower seats to block fluid flow, enabling consistent operations and fluid flow management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the inner diameter of seats decreases as you move down the tubular, then plug elements can pass through upper seats to land on lower seats, but the inner diameter through the tool is not constant

Engineering Contradiction:

Improveplug element passageVSAvoidinner diameter consistency

Core Design Contradiction:

Ease of operationVSShape

Solution Approach 1:

The plug element is designed with an asymmetric geometry featuring a rounded leading end and a tapered trailing end. This asymmetric shape allows the plug to pass through upper seats with larger inner diameters and land on lower seats with smaller inner diameters, while the tool itself maintains a constant inner diameter throughout its length.

Inventive Principle:

Principle #4Asymmetry

2Shape

If the inner diameter of seats is constant throughout the tubular, then the tool has consistent diameter for fluid flow, but plug elements cannot pass through upper seats to land on lower seats

Engineering Contradiction:

Improveinner diameter consistencyVSAvoidplug element passage

Core Design Contradiction:

ShapeVSEase of operation

Solution Approach 1:

The asymmetric plug design with rounded leading end and tapered trailing end enables passage through constant diameter seats. The rounded leading end enters the seat opening first, followed by the tapered trailing end, allowing the plug to navigate through seats of uniform diameter while maintaining the tool's consistent inner diameter.

Inventive Principle:

Principle #4Asymmetry

3Reliability

If traditional spherical plug elements are used, then they can block fluid flow effectively, but they cannot pass through seats with varying inner diameters

Engineering Contradiction:

Improvefluid flow blockingVSAvoidseat compatibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The asymmetric plug geometry with rounded leading end and tapered trailing end provides adaptability to seats with varying inner diameters. The rounded leading end facilitates entry into seats, while the tapered trailing end allows the plug to navigate through transitions between seats of different diameters, maintaining both fluid flow blocking capability and seat compatibility.

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentUS8668018B2Selective dart system for actuating downhole tools and methods of using same

Publication Date: 2014.03.11 BAKER HUGHES CO

AI summary

Plug element systems comprise a tubular member having at least two seats. An eccentrically-shaped plug member comprises an upper end portion and a lower end portion. The upper end portion comprises an upper end diameter can be less than, greater than, or equal to a lower end portion diameter of the lower end portion. The eccentric shape of the plug member permits it to pass through a first seat and land on a second seat comprising a second seat length where both the first seat and the second seat comprise substantially equal inner seat diameters.