Drill String Clutch Assembly for BHA Stress and Drag Relief
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Solution Overview
Problem
Conventional drill strings face challenges during tripping out and back reaming procedures due to the stress exerted on expensive components like rotary steerable systems, as rotation and circulation stoppages lead to destructive forces on the BHA, causing undergauge boreholes and stuck drill pipes.
Innovation Solution
A clutch and circulation system comprising a driveshaft, shuttle, and actuation mechanism that allows selective rotation and fluid diversion, enabling the clutch assembly to engage or disengage the downhole portion from the uphole portion and the circulation assembly to open or close, reducing drag and stress on the BHA by diverting fluid flow to the annulus during tripping or back reaming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If rotation and circulation are stopped during tripping out, then the drill string can be pulled out of the borehole, but significant stress is placed on the BHA including expensive components like rotary steerable systems
Solution Approach 1:
The system segments the drill string into uphole and downhole portions that can rotate independently through the clutch assembly. This allows the uphole portion to be pulled out while the downhole portion with the BHA remains stationary or rotates independently, preventing stress transmission to expensive components like rotary steerable systems
Solution Approach 2:
The clutch assembly acts as an intermediary mechanism between the uphole and downhole portions of the drill string. It selectively engages or disengages the connection, allowing controlled independent rotation and preventing direct stress transmission during tripping operations
2Reliability
If circulation continues during tripping out, then drilling fluid continues to flow, but this generates drag on the BHA that can cause stuck drill pipe
Solution Approach 1:
The circulation system dynamically switches between open and closed states through the circulation assembly. During tripping operations, the circulation assembly closes to stop fluid flow through the drill string, eliminating drag forces on the BHA while preventing stuck pipe conditions
Solution Approach 2:
The system periodically switches circulation states based on operational requirements. During tripping, circulation is closed; during drilling, circulation opens. This periodic action optimizes both drag prevention and stuck pipe avoidance
3Strength
If the clutch assembly allows independent rotation of uphole and downhole portions, then stress on BHA is reduced, but the device complexity increases
Solution Approach 1:
The system merges the clutch assembly and circulation assembly into a single integrated unit with a unified actuation mechanism. This combination reduces overall device complexity while maintaining the stress-reduction benefits of independent rotation capability
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 system reduces the stress on the BHA by allowing independent rotation of the uphole and downhole portions, minimizing drag and preventing damage to the rotary steerable system during tripping out and back reaming, thereby enhancing the drilling process and reducing the risk of stuck pipes.
Implementation Method 1
the circulation assembly to open or close, reducing drag and stress on the BHA by diverting fluid flow to the annulus during tripping or back reaming
Implementation Method 2
reducing drag and stress on the BHA by diverting fluid flow to the annulus during tripping or back reaming
Data Source
AI summary
Clutch assemblies and related systems are provided. In some embodiments, the system comprises the clutch assembly, a circulation assembly, and an actuation mechanism operatively connected to the clutch assembly and the circulation assembly. In some embodiments, the clutch assembly allows for selective rotation of a bottom hole assembly of a drill string and the circulation assembly allows for selective exhausting of drilling fluid from the drill string. Related drill strings and methods for drilling a borehole are also provided.