Pipeline Pig Launching with Flow-Blocking Spheres
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Solution Overview
Problem
Existing pig launchers for pipelines, particularly in the offshore oil and gas industry, face challenges in launching multiple pigs efficiently and reliably, especially when submerged, due to their complexity, bulkiness, and high costs, requiring frequent removal and repositioning, which is impractical and expensive.
Innovation Solution
A method and launcher design that uses a series of launching elements, such as spheres, to interact with pigs within the pipeline, blocking fluid flow and creating a pressure differential to launch successive pigs, with a mechanism that allows controlled release and engagement with each pig to ensure sequential launch without complex valve systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a pig launcher contains only one pig with simple piping and valve arrangements, then the launcher is compact and simple, but it must be reloaded with another pig after each pig is launched which requires repeatedly opening an end cap containing pressurised fluid
Solution Approach 1:
The launcher is divided into multiple chambers (first chamber, second chamber, third chamber) that can be independently sealed and pressurized. Each chamber can contain and launch a pig separately, allowing sequential launch without opening the end cap. The end cap remains closed throughout the operation, maintaining pressurized fluid containment while enabling multiple launches.
2Ease of operation
If a pig launcher contains two or more pigs with separate pressure inlets and valves for each pig, then successive pigs can be launched separately, but the launcher becomes complex, bulky and expensive
Solution Approach 1:
A single pressure inlet and valve system serves multiple chambers sequentially. The valve directs pressurized fluid to different chambers in sequence, allowing one valve and inlet to perform the function of multiple valves and inlets would traditionally require. This reduces complexity while maintaining sequential launch capability.
Solution Approach 2:
The valve is dynamically repositioned to direct fluid flow to different chambers as needed. Rather than having fixed connections to each chamber, the movable valve dynamically routes pressurized fluid to the chamber whose pig is to be launched next, enabling flexible sequential operation with minimal piping.
3Adaptability or versatility
If a multiple pig launcher is removed from a subsea pipeline after use, then it can be re-used elsewhere, but this requires the great expense of additional vessel intervention on site and proper sealing of the access opening
Solution Approach 1:
The launcher is designed as a disposable or long-term permanent installation rather than a removable component. Given that the launcher becomes complex and costly anyway, the design accepts that it will remain installed in the subsea pipeline for its entire service life, eliminating the need for expensive removal operations while enabling multiple pig launches.
4Loss of time
If a pig launcher is left underwater for the entire life of the pipeline, then removal is avoided, but ensuring safe and reliable operation would require extremely stringent and expensive design parameters
Solution Approach 1:
The launcher is pre-filled with multiple pigs and designed for long-term permanent installation with all necessary sealing and pressurization systems in place before deployment. The end cap is sealed once during installation, and the system is designed to operate reliably for the entire pipeline life without requiring removal or maintenance access, accepting the stringent design requirements as necessary for permanent subsea service.
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 simple, reliable, and cost-effective sequential launch of multiple pigs into a pipeline, reducing the need for frequent removal and repositioning, and ensuring safe operation over extended periods without complex and costly design modifications.
Implementation Method 1
conveying a launching element to the pig by entraining the launching element in the flow of fluid
Implementation Method 2
blocking the flow of fluid through the pig to launch the pig
Data Source
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AI summary
A pipeline pig is launched by directing a flow of fluid to, and through, the pig while conveying a launching element to the pig, entrained in the flow. Interaction between the launching element and the pig then blocks the flow through the pig to launch the pig. The launching element may be a spherical plug that blocks a through-passage extending longitudinally through the pig, hence serving as a barrier to the flow through the pig, or may trigger a blocking mechanism that blocks the flow through the pig. The flow entraining the launching element may be directed through at least one other pig to be launched subsequently, positioned upstream of the pig being launched. A succession of launching elements may be released into the flow, each being configured to interact with a respective one of a series of pigs. Successively-released launching elements may increase in diameter from element to element.