Drill String Clutch Assembly for Low-Stress BHA Extraction
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Solution Overview
Problem
Conventional drill strings face issues with undergauge boreholes and stress on expensive components like rotary steerable systems due to tripping out and back reaming procedures, which can lead to damage during drilling operations.
Innovation Solution
A clutch and circulation system with a clutch assembly and actuation mechanism that allows selective rotation and fluid diversion, reducing drag on the BHA by disengaging the downhole portion from the uphole portion and diverting fluid flow to the annulus during tripping or back reaming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If tripping out and back reaming procedures are used to handle undergauge boreholes and stuck drill pipe, then the drill string can be extracted or reamed, but significant stress is placed on the BHA including expensive components like rotary steerable systems
Solution Approach 1:
The drill string is segmented into an uphole portion and a downhole portion that can be independently rotated. The clutch assembly allows the uphole portion to be disconnected from the downhole portion, enabling the uphole portion to be rotated during tripping out while the downhole portion remains stationary, thereby reducing stress on the BHA components.
Solution Approach 2:
The clutch assembly provides dynamic control over the rotational connection between the uphole and downhole portions. During normal drilling, the clutch engages to rotate the downhole portion with the uphole portion. During tripping out, the clutch disengages to allow independent rotation of the uphole portion, adapting the system's rotational behavior to different operational phases.
2Reliability
If the drill string is rotated during tripping out to prevent sticking, then circulation can be maintained, but drag on the BHA increases causing significant stress on components
Solution Approach 1:
The rotational motion is segmented between the uphole and downhole portions. The clutch assembly enables the uphole portion to rotate independently while the downhole portion remains stationary during tripping out operations. This segmentation allows circulation to be maintained through rotation of the uphole portion without subjecting the BHA to the drag forces that would result from rotating the entire drill string.
3Device complexity
If conventional drill strings are used without selective rotation capability, then the structure is simpler, but the BHA components are vulnerable to damage during tripping out and back reaming
Solution Approach 1:
The drill string is divided into separable rotational zones using the clutch assembly. This segmentation allows the uphole portion to be rotated during tripping out while the downhole portion with expensive BHA components remains stationary, protecting these components from damage while maintaining a relatively simple overall structure.
Solution Approach 2:
The clutch assembly introduces dynamic control capability to the drill string structure. It allows the system to switch between engaged and disengaged states, enabling selective rotation of the uphole portion during tripping out operations. This dynamic capability protects BHA components from damage without requiring a completely complex structural redesign.
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.