Coilable Drill String Reel System for Fast Tripping
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Solution Overview
Problem
Current drilling systems face inefficiencies due to long tripping times and logistic challenges associated with sectional tubing and coiled tubing methods, as they either suffer from slow tripping speeds or increased risk of equipment sticking due to friction, and handling heavy equipment.
Innovation Solution
A drilling system that uses a coilable drill string stored on a reel, allowing rotation from the top side and disconnection from the reel at the well side for faster spooling, combining the advantages of sectional and coiled tubing while minimizing their drawbacks, utilizing composite materials for enhanced torsional stiffness and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If coiled tubing is used for drilling, then tripping speed is significantly faster than sectional tubing, but the risk of equipment getting stuck increases due to friction and torque control becomes dependent on mud circulation
Solution Approach 1:
The drill string is segmented into a coiled tubing portion for fast tripping operations and a sectional drill pipe portion for reliable torque transmission and rotation. This segmentation allows each part to perform its optimal function: the coiled tubing provides high-speed retrieval while the drill pipe sections provide stable rotational control and reduced friction through their rigid structure.
Solution Approach 2:
The system merges coiled tubing and sectional drill pipe into a hybrid configuration where both types of tubing are connected in series. The coiled tubing is spooled from a reel for rapid deployment and retrieval, while the drill pipe sections are connected with threaded joints to provide rigid torque transmission and enable rotation from topside, thereby combining the speed advantage of coiled tubing with the reliability of sectional tubing.
2Ease of operation
If top drive is used for lifting and rotating drill string from topside, then torque control is good and friction for axial movements is reduced, but tripping times are long due to the need to make up and break out numerous threaded connections
Solution Approach 1:
The drill string is divided into a coiled tubing section that requires no threaded connections for tripping operations and a drill pipe section that maintains threaded connections for rotation. This segmentation allows the coiled tubing portion to be rapidly spooled in and out without making or breaking connections, dramatically reducing tripping time while the drill pipe portion retains the ability to be rotated from topside when needed.
Solution Approach 2:
The coiled tubing enables continuous, uninterrupted tripping operations without the need to stop and make up or break out threaded connections. The reel-driven spooling mechanism maintains continuous motion during tripping, eliminating the time losses associated with repeated connection and disconnection operations while preserving the ability to rotate the drill string when drilling operations require it.
3Adaptability or versatility
If coiled tubing is used with downhole motor, then drill bit rotation is achieved, but torque output is significantly lower than top drive and drilling performance cannot be optimized independently of mud flow conditions
Solution Approach 1:
The system combines coiled tubing with a downhole motor for situations where rotation at the bit is required but high torque is not critical, while maintaining the option to use drill pipe sections with top drive rotation for high-torque applications. This merging provides versatility in drilling methods, allowing selection based on specific operational requirements.
Solution Approach 2:
The system dynamically adapts its configuration based on operational needs. The coiled tubing with downhole motor is used when flexibility and rapid tripping are priorities and high torque is not required, while drill pipe sections with top drive rotation are deployed when maximum torque output is needed. This dynamic selection optimizes performance for different drilling scenarios.
4Strength
If a long coiled drill string is provided as one piece, then torsional stiffness is sufficient for rotation, but the reel becomes very heavy and logistic challenges increase
Solution Approach 1:
The drill string is segmented into multiple drill pipe sections connected by threaded joints rather than being provided as one continuous long piece. This segmentation reduces the length of coiled tubing that must be spooled from the reel, thereby reducing the reel's weight and associated logistic challenges while maintaining sufficient torsional stiffness through the rigid drill pipe sections that can be rotated from topside.
Data Source
AI summary
Disclosed is a drilling system and a method for drilling a well. The drilling system includes a coilable drill string; a first reel for storing the coilable drill string; a drive means for driving the coilable drill string into the well from the first reel and out of the well to the first reel; and a deflection means for directing the coilable drill string between the first reel and into the well centre. The drilling system further includes a top drive. The coilable drill string is provided with: a first connection at a first end for connecting the coilable drill string to a bottom-hole-assembly and a second connection at a second end for connecting the coilable drill string to the top drive.