Controlled Local Reaction Tool for Hydrate and Paraffin Duct Unblocking
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Solution Overview
Problem
Existing methods for unblocking undersea oil well ducts obstructed by hydrates or paraffins are inefficient, risky, or costly, particularly when configurations are complex or when conventional tools like flexitubes and cleaning pigs fail, leading to production interruptions and high costs.
Innovation Solution
A system using a robot connected via an umbilical cable with independent reservoirs for solutions A and B, controlled by pumps and valves, generates a controlled exothermic reaction at the obstruction site by mixing these solutions, utilizing a reactor and diffusor to manage the reaction and dissolve blockages effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If depressurization technique is used to unblock hydrate obstructions, then the hydrate can be broken up and removed, but large pressure differential causes the hydrate to move at high speed towards the SPU causing damage upon arrival
Solution Approach 1:
A flexible robot tool acts as an intermediary device between the depressurization system and the hydrate obstruction. The robot navigates to the obstruction, contains the depressurization action locally, and prevents uncontrolled high-speed movement of hydrate fragments toward the SPU, thereby resolving the contradiction between unblocking efficiency and prevention of damage
Solution Approach 2:
The depressurization action is applied locally at the obstruction site through the robot rather than globally from the SPU. This localized approach breaks up hydrates in situ while containing the pressure differential effects, preventing the harmful high-speed movement of large hydrate masses toward the SPU
2Productivity
If flexitube is inserted from the SPU to unblock hydrates, then the line can be depressurized and hydrate broken up, but the method is not applicable in complex configurations or when obstruction is far from vertical section
Solution Approach 1:
The system transitions from a static flexitube inserted from the SPU to a dynamic robot that can actively navigate and adapt to various riser configurations. The robot's ability to move independently through complex geometries and reach obstructions anywhere in the line provides the versatility needed to operate in different configurations regardless of obstruction location
Solution Approach 2:
The robot is self-propelled and autonomously navigates to the obstruction without requiring insertion from the SPU. This self-service capability allows the system to reach obstructions in complex configurations independently, eliminating the limitation of requiring specific riser geometries or proximity to vertical sections
3Productivity
If cleaning pig is used to remove paraffin obstruction, then the duct can be cleaned before complete obstruction, but the pig gets stuck during operation
Solution Approach 1:
The system replaces the mechanical cleaning pig with a robot equipped with a chemical reaction system. Instead of relying on mechanical scraping that can get stuck, the robot delivers chemical reagents that dissolve paraffin obstructions, eliminating the risk of the tool becoming lodged while maintaining effective cleaning capability
4Productivity
If probe access with flexitube from ANM is used to depressurize line, then hydrate breakup occurs, but the operation takes months and has extremely high cost
Solution Approach 1:
The robot is deployed directly to the obstruction location and performs the depressurization and hydrate breakup operation immediately upon arrival. This eliminates the lengthy multi-month process required by probe access methods, as the robot is already positioned at the problem site and can execute the unblocking operation without delay
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
Enables efficient and controlled removal of hydrates and paraffins, reducing reaction risks and costs, and minimizing production downtime by ensuring precise application of chemical reactions directly at the obstruction.
Implementation Method 1
generates a controlled exothermic reaction at the obstruction site by mixing these solutions
Data Source
AI summary
The present invention proposes the use of a tool (13) that is connected to a device for locomotion, such as, for example, a robot, and provided with an umbilical cable (06) to bring about a controlled reaction near the blockage, in order to remove it. In order to carry out that controlled reaction, an injection, and control system is used, which may be a closed loop control system.