Mechanical Perforator Hydraulic Reset and Slip Anchoring

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Solution Overview

Problem

Existing mechanical perforators for well casing strings lack the ability to reliably move perforator blades from a retracted to a cutting position and back, making them difficult to relocate within a cased wellbore, especially when faced with differential pressure downhole.

Innovation Solution

A mechanical perforator design featuring a perforator module with multiple blades supported by upper and lower end cones, a linear force generator, and a slip module that allows for reliable anchoring and movement of the perforator within the well casing, enabling the blades to perforate and retract for repeated use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a compression spring is used to return cutter blocks to retracted position, then the tool can reset after perforation, but differential pressure downhole overpowers the spring and prevents resetting

Engineering Contradiction:

Improvereset reliabilityVSAvoiddifferential pressure

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The patent inverts the force application mechanism by using a hydraulic piston to actively push the cutter blocks to the retracted position rather than relying on a passive spring to return them. This reversal of the force direction allows the system to overcome differential pressure that would otherwise prevent resetting.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent employs hydraulic pressure transmitted through a fluid-conveying passage to drive the piston, which in turn moves the cutter blocks to the retracted position. This hydraulic mechanism provides sufficient force to overcome downhole differential pressure, enabling reliable resetting under conditions where mechanical springs fail.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Productivity

If a single cutter punches one hole at a time, then the device is simple, but productivity is low

Engineering Contradiction:

Improveperforation rateVSAvoidcutter configuration

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent combines multiple cutter blocks (at least two, preferably three or four) into a single integrated perforating tool assembly. These cutters are arranged radially around the central axis and can simultaneously perforate multiple holes in the casing, thereby multiplying productivity while maintaining manageable structural complexity through symmetric radial arrangement.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If the perforator is anchored in the wellbore, then positioning is stable, but the perforator cannot be relocated for repeated use

Engineering Contradiction:

Improvepositioning stabilityVSAvoidrelocation capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements a dynamic anchoring system using slips that can transition between engaged and disengaged states. The slips engage with the casing interior to provide stable positioning during perforation operations, then can be disengaged to allow the perforator to be moved to new locations for repeated use, thus providing both stability and adaptability.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS10947802B2Mechanical perforator

Publication Date: 2021.03.16 EXACTA FRAC ENERGY SERVICES INC

AI summary

A mechanical perforator includes a perforator module and a slip module. The perforator module has perforator blades that may be forced outwardly to perforate a well casing joint after slips of the slip module has been deployed to bite the well casing and anchor a lower end of the mechanical perforator in the well casing.