Downhole Mill Serrated Cutters and Pump-Off Sub Release
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing downhole mills face challenges in efficiently drilling out bridge plugs, particularly due to limitations in cutter design and release mechanisms, which affect penetration rates and operational reliability.
Innovation Solution
A downhole mill with a combination of serrated and non-serrated cutters, along with a pump-off sub featuring a c-ring and latch mandrel mechanism, allows for effective cutting and secure detachment from the mill assembly, enabling efficient drilling and reduced operational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional downhole mills use conventional cutter designs, then the structure is simpler, but the penetration rate is lower
Solution Approach 1:
The patent applies local quality by differentiating between serrated cutters (with toothed surfaces for aggressive cutting) and non-serrated cutters (with smooth surfaces for stable rotation). This localized variation in cutter characteristics optimizes the overall milling performance by combining the advantages of both cutter types in specific positions around the mill assembly.
Solution Approach 2:
The patent employs composite materials by combining serrated and non-serrated cutter surfaces in a single mill assembly. This composite approach allows the mill to utilize both the high penetration capability of serrated surfaces and the rotational stability of non-serrated surfaces, achieving superior overall cutting performance.
2Force
If a pump-off sub with c-ring mechanism is used for mill detachment, then the separation forces are reduced, but the device complexity increases
Solution Approach 1:
The patent applies dynamics by using a movable c-ring that can transition between expanded (locked) and collapsed (released) states. This dynamic mechanism allows the pump-off sub to maintain secure connection during milling operations while enabling easy detachment when needed, reducing the forces required for separation compared to static locking mechanisms.
Solution Approach 2:
The patent uses the c-ring as an intermediary element between the pump-off sub and the mill assembly. This intermediary component facilitates controlled detachment by providing a mechanical interface that can be actuated to release the connection, thereby reducing the direct separation forces required between the main components.
3Productivity
If the mill assembly includes both serrated and non-serrated cutters, then the cutting efficiency is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the cutter assembly into distinct serrated and non-serrated sections. This segmentation allows for specialized manufacturing of each cutter type using appropriate processes (e.g., serrated cutters may be manufactured with toothed surfaces while non-serrated cutters have smooth surfaces), and the segmented design simplifies the overall manufacturing by allowing modular assembly of different cutter types.
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 solution enhances penetration rates and operational reliability by utilizing serrated cutters for efficient cutting and a reliable c-ring mechanism for secure detachment, reducing tool length and separation forces, thus improving milling operations.
Implementation Method 1
a first serrated cutter blade having a plurality of peaks and valleys along its length, a second serrated cutter blade having a plurality of peaks and valleys along its length
Implementation Method 2
used primarily to cut or grind material (e.g. metal, plastic, composite, etc.) at various downhole locations
Implementation Method 3
a detachable connection maintained by an expandable c-ring in an expanded state
Implementation Method 4
The latch mandrel is configured to maintain the c-ring in the expanded state with a radial upset
Implementation Method 5
when the latch mandrel is axially displaced by a ball dropped down the bore of a work string
Implementation Method 6
a ball dropped down the bore of a work string connected to a proximal end of the pump-off sub
Data Source
AI summary
A downhole mill includes a plurality of cutters extending generally radially from a center region to a gage diameter, wherein the plurality of cutters includes a first serrated cutter blade having a plurality of peaks and valleys along its length. The plurality of cutters includes a second serrated cutter blade having a plurality of peaks and valleys along its length. The plurality of cutters includes a non-serrated cutter blade positioned upon the cutting face between the first serrated cutter blade and the second serrated cutter blade, wherein the peaks of the first serrated cutter blade is radially aligned with the valleys of the second serrated cutter blade. A pump-off sub configured to release a downhole mill includes a dovetail connection maintained by a c-ring in an expanded state.