Hybrid Drill String Segmentation for Torque and Flexibility
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Solution Overview
Problem
Current drilling technologies in the oilfield often require a choice between coiled tubing and jointed pipe, limiting the flexibility and efficiency of wellbore operations, as coiled tubing is prone to failure under torque while jointed pipe is not easily rotated in situ.
Innovation Solution
A system combining a rigid tubular string with a non-rigid coiled tubing string, connected via a stabilizer and motor system that allows for both surface and downhole rotation, enabling efficient energy transmission and stability during drilling operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If coiled tubing is used for drilling operations, then flexibility and ease of operation are improved, but reliability deteriorates due to torque-induced failure
Solution Approach 1:
The drill string is segmented into two distinct sections: a rigid tubular section (jointed pipe) for the upper portion and a non-rigid tubular section (coiled tubing) for the lower portion. This segmentation allows each section to perform its optimal function - the rigid section provides torque resistance and structural stability, while the non-rigid section provides flexibility and ease of operation in the drilling zone.
2Reliability
If jointed pipe is used for drilling operations, then reliability and torque resistance are improved, but ease of operation deteriorates due to difficulty in rotating in situ
Solution Approach 1:
The drill string is divided into rigid and non-rigid sections, placing the rotatable non-rigid tubular section at the bottom where it can freely rotate to drive the drill bit, while the rigid upper section maintains structural integrity and torque resistance.
Solution Approach 2:
A connector section is introduced as an intermediary element between the rigid and non-rigid tubular sections. This connector facilitates the transition of rotational motion from the rigid section to the non-rigid section, enabling the rigid pipe to effectively drive the drill bit through the flexible section.
3Adaptability or versatility
If a hybrid string combining rigid and non-rigid tubular is used, then adaptability and versatility are improved, but device complexity increases
Solution Approach 1:
The hybrid drill string is segmented into three main components: rigid tubular section, connector section, and non-rigid tubular section. This segmentation provides adaptability by allowing different combinations and configurations of these sections to be used based on specific operational requirements, while maintaining a relatively simple overall structure.
Data Source
AI summary
An apparatus for performing a drilling operation or a non-drilling wellbore operation may include a string that has a rigid tubular, a connector coupled to the rigid tubular, a non-rigid tubular coupled to the connector; and at least one motor positioned along the string. In some embodiments, a plurality of motors may be positioned along the string to rotate one or both of the non-rigid tubular and a drill bit connected to the string. In some embodiments, the connector may be configured to release the non-rigid tubular from the rigid tubular and thereby leave the non-rigid tubular in the wellbore.