Rotatable Cutting Tool for Casing and Formation
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Solution Overview
Problem
Current casing exit tools are inefficient as they require multiple trips into the wellbore to drill through steel casing and rock formations due to the incompatibility of cutting structures for steel and rock, leading to costly and time-consuming operations.
Innovation Solution
A rotatable cutting tool with a first portion configured for cutting steel casing and a second portion for cutting rock formations, allowing both operations to be performed in a single trip by using durable carbide inserts for milling and PDC inserts for drilling, with an axial clearance to prevent jamming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carbide cutting structures are used for milling steel casing, then durability and resistance to deformation are improved, but effectiveness for drilling rock formations deteriorates
Solution Approach 1:
The cutting tool is divided into multiple cutting portions with different materials: a first cutting portion with carbide for milling steel casing and a second cutting portion with PDC for drilling rock formations. This segmentation allows each portion to be optimized for its specific function, resolving the contradiction between durability for steel cutting and effectiveness for rock drilling.
Solution Approach 2:
Different regions of the cutting tool have different material properties tailored to their specific functions. The first cutting portion uses carbide material optimized for steel casing, while the second cutting portion uses PDC material optimized for rock formations. This local quality differentiation resolves the contradiction by providing site-specific material optimization.
2Productivity
If PDC cutting structures are used for drilling rock formations, then drilling effectiveness is improved, but resistance to chipping while milling steel casing deteriorates
Solution Approach 1:
The cutting tool is segmented into a first cutting portion with carbide for steel casing and a second cutting portion with PDC for rock formations. This segmentation protects the brittle PDC material from direct contact with steel casing, preventing chipping while maintaining high drilling effectiveness when engaged with rock formations.
Solution Approach 2:
The first cutting portion with carbide performs preliminary action by milling through the steel casing before the second cutting portion with PDC engages the rock formation. This preliminary action protects the PDC material from chipping by removing the steel casing that would otherwise cause damage.
3Device complexity
If a single cutting structure is used for both steel casing and rock formations, then device complexity is reduced, but reliability due to susceptibility to jamming deteriorates
Solution Approach 1:
The cutting tool uses multiple cutting portions with different materials (carbide and PDC) rather than a single cutting structure. This segmentation prevents jamming by ensuring each material is used in the appropriate application, thereby improving reliability despite increased device complexity.
Solution Approach 2:
The cutting tool employs composite material construction with different materials (carbide and PDC) in different portions. This composite approach allows each material to perform optimally in its designated function, preventing jamming and improving reliability while accepting the complexity of a multi-material design.
4Reliability
If multiple trips are made into the wellbore to perform casing milling and formation drilling separately, then cutting effectiveness for each operation is improved, but operational time and cost increase
Solution Approach 1:
The invention merges the functions of casing milling and formation drilling into a single cutting tool that can perform both operations in one trip. The tool combines a first cutting portion for steel casing and a second cutting portion for rock formations, allowing both operations to be completed sequentially in a single wellbore entry, thereby reducing operational time and cost while maintaining cutting effectiveness.
Solution Approach 2:
The cutting tool is designed with multi-functionality, serving as both a casing mill and a formation drilling tool. By incorporating different cutting portions with appropriate materials for each function, the tool achieves universality, allowing operators to complete both casing milling and formation drilling in a single trip, significantly reducing time and operational costs.
Data Source
AI summary
A method of cutting a casing and a formation includes providing a rotatable cutting tool in a wellbore, wherein the rotatable cutting tool includes a first portion configured for cutting the casing and a second portion configured for cutting the formation. The method further includes engaging the first portion with the casing in the wellbore; and engaging the second portion with the casing after engaging the first portion with the casing.