Casing Slotting Tool for Milling Chip Nest Prevention

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Solution Overview

Problem

The accumulation of long, twisted, and curled metal cuttings during the milling of casings poses a significant challenge, as they form nests around the milling device and work string, making the process difficult and costly, requiring time-intensive manual removal and risking injuries.

Innovation Solution

A method involving longitudinal slotting of casings with a slotting tool to create predetermined breaking points, allowing for effective removal of chips during milling, where the slots are made without separating the casing, and the slotting tool features multiple slotting devices arranged circumferentially to introduce slots that reduce wall thickness and facilitate chip removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If milling is performed on cemented casings, then the casing can be removed to the desired depth, but long and flat milling chips accumulate around the milling device and work string forming cutting nests

Engineering Contradiction:
Improvecasing removal depthVSAvoidmetal cutting nest formation
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The invention introduces longitudinal slots into the casing wall before milling, which segment the continuous metal structure into separated sections. These slots create predetermined breaking points that divide the metal cuttings into smaller, manageable pieces during milling, preventing the formation of long continuous chips that accumulate and form cutting nests around the work string.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The slotting operation is performed as a preliminary action before the actual milling process. By pre-introducing slots at predetermined locations along the casing, the metal structure is weakened and prepared to break into smaller chips during subsequent milling, thereby preventing chip accumulation issues before they occur.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If multiple slotting devices are arranged circumferentially on the slotting tool, then slots can be introduced efficiently without separating the casing, but the device complexity increases

Engineering Contradiction:
Improveslotting efficiencyVSAvoidslotting tool structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention combines multiple slotting devices (at least three) onto a single slotting tool body, allowing them to operate simultaneously or in sequence as one integrated unit. This merging of multiple cutting functions into a single tool significantly improves productivity by creating multiple longitudinal slots in one pass through the casing, while the unified tool structure manages the complexity through coordinated design of the slotting devices around a common base body.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3420178B1Device and method for the longitudinal slotting of casings with a slotting tool and subsequent milling of the previously slotted tube walls
Publication Date: 2020.10.28 RITSCHEL ROBERT
  • EP3420178B1 patent drawingFigure 1~2
  • EP3420178B1 patent drawingFigure 3~4
  • EP3420178B1 patent drawingFigure 5~6

AI summary

The present invention relates to a device and a method for the slotting of casings. The device comprises a slotting tool and is provided for the longitudinal slotting of casings in order to subsequently mill the previously slotted areas of the casing in order to remove in this manner the pipe walls of the casing.