Splined Workstring Connections for Coiled Tubing Wellbore Advancement
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Solution Overview
Problem
Existing systems face challenges in efficiently advancing tubular strings through wellbores, particularly in horizontal sections, due to high friction and the difficulty in connecting vibratory tools without causing rotation or unthreading issues, especially when using coiled tubing.
Innovation Solution
The use of a connecting tool with a sliding, splined engagement and a threaded outer sleeve allows for secure, leak-proof, high-tensile, high-torque connections between coiled tubing sections without requiring significant rotation, combined with vibratory tools activated by fluid flow or plugs, enabling effective friction reduction and tool activation during deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional threaded connections are used to connect coiled tubing sections, then secure connections are achieved, but significant rotation is required which causes unthreading issues and operational difficulties
Solution Approach 1:
The connection system is divided into two functional components: a splined engagement mechanism for alignment and preliminary connection, and a threaded outer sleeve for final securement. This segmentation allows the connection process to occur in distinct steps, reducing the rotational burden on any single mechanism and preventing unthreading issues
Solution Approach 2:
The splined engagement mechanism performs preliminary alignment and connection between coiled tubing sections before the threaded outer sleeve is applied. This preliminary action establishes proper positioning and reduces the rotational distance required for the threaded connection, eliminating the need for significant rotation that causes unthreading
2Object-affected harmful factors
If vibratory tools are deployed to reduce friction during tubular string advancement, then friction reduction is achieved, but tool activation and deployment become complex
Solution Approach 1:
The vibratory tools are designed to activate automatically upon deployment into the wellbore, eliminating the need for complex external activation systems. The tools self-regulate their operation based on deployment conditions, reducing system complexity while maintaining effective friction reduction capability
Solution Approach 2:
Fluid flow or plugs are used to activate the vibratory tools during deployment. This hydraulic/pneumatic activation method simplifies the control system compared to mechanical or electrical activation, reducing device complexity while achieving effective friction reduction
3Productivity
If coiled tubing is used for deployment, then continuous tubing advancement is achieved, but connection and retrieval operations become difficult
Solution Approach 1:
The coiled tubing system is segmented into connectable sections with standardized splined engagement and threaded connection interfaces. This allows continuous tubing to be assembled in manageable sections that can be easily connected and retrieved, maintaining deployment efficiency while improving operational ease
Solution Approach 2:
The connecting tool design provides multi-functionality by enabling both secure connection during deployment and controlled disconnection during retrieval through the same splined engagement and threaded sleeve mechanism. This universal design simplifies both connection and retrieval operations without requiring separate systems
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
This method facilitates efficient advancement of tubular strings with reduced friction and secure connections, allowing for seamless deployment and retrieval of vibratory tools, enhancing well operations like frac plug drilling without surface retrieval.
Implementation Method 1
Vibrations, impacts or pressure pulses generated by a vibratory tool can reduce or eliminate differential sticking and/or static friction between a tubular string and a wall of a wellbore
Implementation Method 2
The sliding, splined engagement and threaded outer sleeve allow for secure, leak-proof, high-tensile, high-torque connections between coiled tubing sections without requiring significant rotation
Data Source
AI summary
A system for use with a subterranean well can include a bottom hole assembly connected at a distal end of a tubing section, and another bottom hole assembly connected between the tubing section and another tubing section that comprises continuous coiled tubing. A method of performing a well operation can include deploying a tubular string into a wellbore, the tubular string comprising multiple tubing sections, a bottom hole assembly connected at a distal end of one of the tubing sections, and another bottom hole assembly connected between two tubing sections. An uphole tubing section comprises continuous coiled tubing. The tubular string is retrieved from the wellbore. The deploying and the retrieving are performed in a single trip of the tubular string into the wellbore.