Wellhead Isolation Tool with Pack-Off Cups for Rig-Free Pressure Testing
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Solution Overview
Problem
Existing wellhead systems face challenges in withstanding extreme conditions such as high pressure, abrasive and corrosive fluids, and temperature changes, leading to weakened integrity and sealing issues, and require pressure testing before high-pressure operations without the need for drilling or workover rigs.
Innovation Solution
A wellhead isolation tool with a hydraulic assembly and pack-off cup assembly, allowing pressure testing of wellheads using pressurized fluid circulation in the annulus between the mandrel and wellhead, sealing with elastomer cups that compress to enhance sealing contact, enabling pressure testing up to 15,000 psi without a drilling or workover rig.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cup type testers are used for pressure testing wellheads, then pressure testing capability is achieved, but the requirement for drilling or workover rigs increases device complexity and operational constraints
Solution Approach 1:
The invention extracts the pressure testing function from the complex drilling or workover rig system by providing a standalone wellhead isolation tool that can be installed directly on the wellhead. This separates the essential pressure testing capability from the heavy equipment infrastructure, allowing testing to be performed independently without requiring the entire drilling or workover rig system.
Solution Approach 2:
The wellhead isolation tool is designed as a universal device that can be installed on various wellheads to perform pressure testing operations. It combines multiple functions (isolation, sealing, pressure application, and testing) into a single tool that can operate independently of drilling or workover rigs, making it applicable to different wellhead configurations and testing scenarios.
2Productivity
If wellheads are exposed to extreme conditions during exploitation, then production operations can be conducted, but well integrity deteriorates due to high pressure, abrasive and corrosive fluids, and temperature changes
Solution Approach 1:
The invention applies beforehand cushioning by installing the wellhead isolation tool and its sealing elements (packer, seal elements) prior to high-pressure operations. These sealing components are positioned in advance to create protective barriers that cushion the wellhead and tubing from the damaging effects of high-pressure abrasive and corrosive fluids, preventing direct exposure and subsequent integrity deterioration.
Solution Approach 2:
The wellhead isolation tool acts as an intermediary device between the wellhead/tubing system and the extreme external conditions. The seal elements and isolating components serve as mediators that prevent direct contact between the well integrity-critical components and the harmful high-pressure abrasive and corrosive fluids, thereby protecting the well structure while allowing production operations to proceed.
3Reliability
If pack-off cups are designed with frustum shape and elastomer material, then sealing effectiveness is improved under high pressure, but device complexity increases due to multiple cups and hydraulic actuation
Solution Approach 1:
The invention utilizes parameter changes by employing elastomer material for the pack-off cups that can change its physical properties (compressibility, elasticity) in response to pressure changes. The frustum shape parameters are optimized to facilitate controlled compression and sealing. The hydraulic system enables dynamic parameter adjustment of the cup compression force, allowing the sealing effectiveness to adapt to varying pressure conditions while managing the complexity through intelligent material and geometric design.
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 tool ensures safe and efficient pressure testing of wellheads, enhancing safety and extending equipment life, eliminating damage to valves, and reducing the need for well killing during high-pressure operations.
Implementation Method 1
The at least one cup is configured to compress in response to circulation of a pressurized fluid in an annulus between the mandrel and the wellhead
Implementation Method 2
a hydraulic assembly including at least one hydraulic line fluidly and a setting tool hydraulic ram
Implementation Method 3
circulating a pressurized fluid into the annulus between the mandrel and the wellbore tubing; pressure testing the wellhead with the pressurized fluid
Data Source
AI summary
A wellhead isolation tool includes a hydraulic assembly including a hydraulic line fluidly and a setting tool hydraulic ram that includes a mandrel head; a mandrel coupled to the hydraulic ram and including an uphole end and a downhole end configured to sting into a wellhead; a packing assembly including a bore that is configured to receive the mandrel; and a pack-off cup assembly coupled to the downhole end. The pack-off cup assembly includes a cup mounted on the mandrel and including a circular frustum that includes an uphole end defined by a first diameter; a downhole end opposite the uphole end and defined by a second diameter less than the first diameter; a bore that extends between the uphole end and the downhole end and is configured to receive a least a portion of the mandrel; and a radial surface between the uphole and downhole ends.