Hydrogen Well Workover Sealing With Buffer Fluid Pressure Zones
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Solution Overview
Problem
The high flammability, low ignition energy, and difficulty in containing hydrogen gas pose significant risks during tubular string operations in pressurized hydrogen-filled wells, leading to potential leakage and explosion hazards.
Innovation Solution
A workover system with at least three BOPs and a pressure conditioning system that uses inert gases or nitrogen to fill and pressurize the string passage sections, maintaining a controlled environment to prevent hydrogen leakage and ensure safe stripping operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tubular string operations are performed in pressurized hydrogen-filled wells, then oil or gas production can be maintained or enhanced, but the risk of hydrogen leakage and explosion increases due to hydrogen's high flammability and low ignition energy
Solution Approach 1:
The patent introduces a buffer fluid as an intermediary substance that fills the annular space between the tubular string and wellbore wall. This buffer fluid acts as a mediator that prevents direct contact between hydrogen gas and the tubular string during operations, thereby eliminating the explosion risk while allowing continuous production operations to proceed
Solution Approach 2:
The patent creates an inert environment by filling the annular space with a buffer fluid that displaces hydrogen gas. This inert atmosphere prevents hydrogen from coming into contact with potential ignition sources during tubular string operations, resolving the contradiction between maintaining production and preventing explosion hazards
2Ease of operation
If the tubular string is moved during operations in a pressurized hydrogen well, then maintenance or production adjustments can be performed, but hydrogen leakage risks increase due to hydrogen's light-weight nature and difficulty in containment
Solution Approach 1:
The buffer fluid serves as an intermediary barrier that contains hydrogen in the wellbore while allowing the tubular string to move freely within the protected zone. This mediator enables operational flexibility while preventing hydrogen escape to the surface
Solution Approach 2:
By maintaining an inert buffer fluid environment in the annular space, the system allows tubular string movement operations while the buffer fluid continuously prevents hydrogen leakage, resolving the contradiction between operational ease and leakage prevention
3Reliability
If multiple BOPs are used to seal around the tubular string, then hydrogen containment is improved, but the device complexity increases
Solution Approach 1:
The patent divides the wellbore into multiple sealed zones using several BOPs positioned at different locations. Each BOP independently seals a specific section, and the buffer fluid fills the spaces between them. This segmentation approach enhances containment reliability by creating multiple barriers while managing complexity through modular positioning
Solution Approach 2:
The buffer fluid creates an inert environment that works in conjunction with the segmented BOP arrangement. The inert atmosphere simplifies the containment strategy by providing a passive safety mechanism that reduces the burden on the mechanical sealing systems, allowing multiple BOPs to be used effectively without proportionally increasing operational complexity
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
The system effectively reduces hydrogen leakage and explosion risks by maintaining a controlled pressure environment, allowing safe movement of tubular strings through hydrogen-filled wells.
Implementation Method 1
A workover system for receiving a tubular string from a wellbore pressurized by hydrogen... a pressure conditioning system configured to fill each of the first and second part of the string passage with a buffer fluid
Implementation Method 2
at least three BOPs defining at least a first part and a second part of a string passage there-between, each BOP being configured to sealingly engage an outer surface of a tubular string
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A workover system for receiving a tubular string from a wellbore pressurized by hydrogen, the system including: - at least three BOPs (5, 6, 7) defining at least a first part (P 1) and a second part (P2) of a string passage there-between, each BOP (5, 6, 7) being configured to sealingly engage an outer surface of a tubular string (T) when the BOP (5, 6, 7) is in a sealing state and to disengage the outer surface of the tubular string (T) when the BOP is in a releasing state; and -a pressure conditioning system (11, 12, 13, 14, 21, 22) configured to fill each of the first and second part (P1, P2) of the string passage with a buffer fluid, in particular during at pressurization period. Also, there is provided a method for moving a tubular string through a wellbore.