Profiled Cementing Plug Seal Surface for High Pressure Hydraulic Integrity
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Solution Overview
Problem
In the oilfield industry, cementing operations face challenges in creating a proper hydraulic seal between cementing plugs and landing collars under high pressure, leading to potential contamination of the cement slurry due to the flat interface between the bottom plug and the cement-made landing collar.
Innovation Solution
The introduction of semi-circular or other profiled sealing ends on cementing plugs, made of molded rubber, which create a better seal when high pressures are applied, reducing the complexity of design and manufacture of landing collars and minimizing damage, while allowing modification of plugs without changing inserts or core materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flat interface is used between the bottom plug and landing collar, then the design and manufacture of landing collars is simpler, but a proper hydraulic seal cannot be created under high pressure
Solution Approach 1:
The patent applies curvature by replacing the flat interface with a semi-circular profile on the bottom plug. This curved sealing surface enables proper hydraulic seal formation under high pressure conditions, resolving the sealing reliability issue while maintaining simple landing collar design since the curvature is integrated into the plug itself rather than requiring complex collar modifications.
2Reliability
If high pressure is applied to force plugs together, then the plugs can be landed, but a proper seal cannot be created due to the flat interface
Solution Approach 1:
The semi-circular profile concentrates and distributes pressure more effectively across the sealing interface compared to a flat surface. This allows the plug to create a proper hydraulic seal at lower pressure levels, reducing the stress required for successful landing while improving seal reliability under operating conditions.
3Reliability
If the plug interface is modified to create better sealing, then seal quality improves, but the complexity of plug design increases
Solution Approach 1:
The sealing profile is merged directly into the bottom plug structure during manufacturing, creating an integrated component rather than requiring separate sealing elements or inserts. This approach improves seal quality while avoiding additional design complexity from multiple components, as the profile is formed as part of the plug body itself.
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 profiled sealing ends enhance the hydraulic seal under high pressures, reducing the risk of hydrostatic or hydrological discharge and improving service quality by maintaining the integrity of the cement slurry during operations.
Implementation Method 1
The plug includes a seal surface having at least one profile... The contact between the bottom plug and the landing collar is usually under high pressure force and, as such, a proper seal cannot always be created
Data Source
AI summary
A plug for displacing cement in a downhole environment comprising a seal surface having at least one profile. The seal surface, in response to applied pressure, creates a hydraulic seal with another device. The seal surface can be made of molded rubber and the profile formed thereon can be formed from the molded rubber and during the molding process. The profile can be a semicircular profile or multiple semicircular profiles. The profile or profiles can be one or more semicircular profiles and one or more line profiles. The plug can be a bottom plug and the seal surface can be an upstream seal surface and the other device can be a float collar. The plug can be a top plug and the seal surface can an upstream seal surface and the other device can be a bottom plug.