Lug-Slot Coupling in Downhole Milling and Whipstock Tools
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Solution Overview
Problem
The challenge of efficiently running a whipstock assembly downhole to reduce trip count in wellbore operations, particularly in multilateral well construction, is addressed by providing a two-part drilling and running tool that allows for the connection and separation of a smaller assembly and a larger bit assembly to facilitate the deployment and retrieval of a whipstock assembly with reduced trips.
Innovation Solution
A two-part drilling and running tool is used, comprising a smaller assembly with cutting features and a larger bit assembly, which can be connected and separated to form a combined bit assembly for milling operations, allowing for the efficient deployment and retrieval of a whipstock assembly with reduced trips, utilizing lug slots and lugs for secure engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a traditional single assembly drilling tool is used, then the tool structure is simple, but the number of trips required for wellbore operations increases
Solution Approach 1:
The drilling tool is divided into two separate assemblies: a smaller assembly that can be retrieved and a larger bit assembly that remains in the wellbore. This segmentation allows the smaller assembly to be pulled out for reuse or replacement without requiring retrieval of the entire tool string, thereby reducing the number of trips required for wellbore operations while maintaining operational simplicity.
2Productivity
If a two-part drilling and running tool is used, then the number of trips is reduced, but the connection and separation mechanisms become more complex
Solution Approach 1:
The smaller assembly is designed to nest within or attach to the larger bit assembly through a standardized interface. The connection mechanism utilizes a lug and slot arrangement where the smaller assembly can be securely coupled to the larger assembly during deployment and easily separated during retrieval operations, providing a simple yet effective connection system that reduces trip count without excessive complexity.
3Reliability
If lug slots and lugs are used for coupling, then the engagement security is improved, but the manufacturing complexity increases
Solution Approach 1:
The lug and slot connection features are strategically positioned at specific locations on the assemblies where they provide maximum engagement security for the critical coupling function. The lug slots are designed with appropriate depth and width to ensure positive engagement while remaining simple to manufacture using standard machining operations. This localized application of the connection feature maintains manufacturing simplicity while achieving reliable engagement.
Data Source
AI summary
Provided is a milling tool, a whipstock assembly, a well system, and a method. The milling tool, in at least one aspect, includes a plurality of blades extending radially outward from a mill body, each of the plurality of blades having a primary surface and first and second side surfaces coupled to opposing sides of the primary surface, adjacent blades of the plurality of blades separated by a spacing. The milling tool may further includes a lug slot extending partially into one of the plurality of blades from the first side surface exposed by the spacing, the lug slot configured to engage with a lug of a related tool to couple the milling tool with the related tool when rotating in a first direction and to disengage from the lug of the related tool to release the milling tool from the related tool when rotating in a second opposite direction.