Subsurface Lubricator Sealing via Wireline Cutting Flapper Valve
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Solution Overview
Problem
Existing oilfield lubricator systems pose safety issues when the lubricator is positioned above the wellhead, as it bypasses the safety of the shutoff valving, allowing gas or fluids to escape when a wireline is inserted through the valving, necessitating a solution to locate the lubricator below the wellhead while maintaining well sealing.
Innovation Solution
A lubricator system incorporating a lubricator cutting flapper valve with a hydraulic piston and cut-off blades that can be actuated to seal the well by cutting the wireline and closing the valve, allowing the lubricator to extend below the wellhead and maintain well pressure containment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the lubricator is positioned above the wellhead, then the wireline can be inserted through the valving, but the safety of the shutoff valving is bypassed and gas or fluids can escape
Solution Approach 1:
The patent inverts the conventional lubricator positioning from above the wellhead to below the wellhead. This inversion allows the lubricator to seal against the bottom of the wellhead valve body, maintaining well pressure containment while enabling wireline insertion through the valve without bypassing safety mechanisms.
Solution Approach 2:
The patent introduces a packer as an intermediary device that creates a seal between the lubricator and the wellhead valve body. This packer enables the lubricator to function effectively when positioned below the wellhead, maintaining the sealing function that would otherwise be provided by the valve.
2Reliability
If the lubricator is positioned below the wellhead, then well pressure containment is maintained, but a sealing mechanism must be implemented to seal the lubricator opening
Solution Approach 1:
The packer is designed to be set and sealed using the existing well pressure itself. The well pressure drives the packer elements to expand and seal against the wellhead valve body, eliminating the need for external sealing mechanisms or additional complexity in the lubricator design.
3Reliability
If the lubricator extends below the wellhead, then safety is improved by maintaining shutoff valving integrity, but the lubricator structure becomes more complex
Solution Approach 1:
The lubricator is designed to perform multiple functions: it provides wireline insertion capability, maintains well pressure containment, and works with the existing wellhead valve system. By positioning it below the wellhead and using the packer sealing mechanism, a single device achieves these multiple functions 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
Enables safe insertion of wirelines and tools into the wellhead while preventing gas or fluid escape, even when the typical wellhead valves are not operational, by extending the lubricator below the wellhead and utilizing a hydraulic piston to cut and seal the wireline, ensuring effective sealing.
Implementation Method 1
a hydraulic piston and cut-off blades that can be actuated to seal the well by cutting the wireline and closing the valve
Data Source
AI summary
The disclosure provides a lubricator system and method for entering the oil/gas wellhead or casing head with a wireline and tool while being able to safely shut or contain well pressure build up. The lubricator is coupled with a lubricator cutting flapper valve and can be attached to a wellhead on the oil/gas well, so that the lubricator extends below the wellhead. The wellhead can be opened, allowing the wireline and tool to enter into the bore. The tool is attached to a wireline cable that is controlled on the surface by means of a spooled drum attached to a portable or mobile machine or equipment. The lubricator cutting flapper valve includes structure that can sever the wireline and seal the lubricator to avoid allowing well gas or fluids to escape if necessary.