Pipeline Hydrostatic Testing Using Actuated Isolation Tools
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Solution Overview
Problem
Existing methods for hydrostatic testing and maintenance of pipelines, especially those submerged or under difficult-to-access locations, face challenges in controlling fluid flow and sealing without draining the pipeline, due to environmental and cost concerns, and require innovative solutions for efficient and cost-effective testing and repair.
Innovation Solution
The use of a pig train system comprising isolation tools and liquid slugs, where isolation tools are propelled by fluid flow, can be remotely actuated to seal the pipeline, and a pumping system is used to increase hydrostatic pressure within the pipeline, allowing for testing without welding or draining, enabling efficient and rapid testing of pipeline sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional hydrostatic testing methods are used requiring pipeline drainage and welding of test heads, then thorough testing can be performed, but the process is time-consuming and disrupts pipeline operations
Solution Approach 1:
The pipeline is divided into test sections isolated by plugging devices, allowing specific segments to be tested independently without draining the entire pipeline. This enables targeted testing while maintaining operations in other sections.
Solution Approach 2:
Plugging devices with packers act as intermediaries to create sealed test sections without permanent modifications. These devices can be inserted and removed without welding, eliminating the need for test heads while enabling thorough hydrostatic testing.
2Ease of operation
If pipeline drainage is performed for testing, then complete fluid flow control is achieved, but environmental damage occurs and product loss increases
Solution Approach 1:
Plugging devices with packers create sealed sections that allow fluid flow control without draining the pipeline. The packers seal against the pipeline interior wall to contain fluid within the test section, eliminating environmental pollution from drainage.
Solution Approach 2:
The need for pipeline drainage is extracted and eliminated by using plugging devices that provide alternative fluid flow control. The test section is isolated using the plugging devices, allowing testing while maintaining fluid containment without environmental harm.
3Ease of operation
If plugging devices are used to isolate pipeline sections, then fluid flow control is achieved without draining, but the devices must be reliably sealed and actuated
Solution Approach 1:
The plugging devices incorporate packers that automatically seal against the pipeline interior wall through radial expansion when actuated. The self-contained design with integrated actuation mechanisms eliminates the need for complex external sealing systems.
Solution Approach 2:
The plugging devices utilize hydraulic or pneumatic actuation mechanisms to expand packers radially against the pipeline wall, creating reliable seals. This allows controlled actuation and release of the plugging devices without complex mechanical systems.
4Device complexity
If isolation tools are propelled by fluid flow through the pipeline, then no external propulsion systems are needed, but control of the tools at selected locations becomes challenging
Solution Approach 1:
The isolation tools incorporate sensors and control systems that detect their position and respond to commands to activate or release at selected locations. This feedback mechanism enables precise control of tool positioning despite fluid flow propulsion.
Solution Approach 2:
External actuation mechanisms serve as intermediaries to control the isolation tools from outside the pipeline. These mechanisms transmit control signals to activate or release the plugging devices at predetermined locations, solving the control challenge of fluid-flow propelled tools.
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
This method allows for faster and lower-cost hydrostatic testing of pipelines, enabling testing during construction and in-service maintenance without disrupting operations, and facilitates leak detection and repair while maintaining operating pressure, thus meeting safety and regulatory requirements.
Implementation Method 1
a pumping system for increasing the hydrostatic pressure interior of the pipeline between spaced apart plugging tools
Implementation Method 2
The isolation tools having means for being propelled by fluid flow (liquid or gas) through the pipeline
Implementation Method 3
at least one sealing pig, slugs of fluid between the sealing pig and plugging tools
Data Source
AI summary
A method of hydrostatic testing a selected section of a pipeline having fluid flow therethrough, including the steps of introducing into the pipeline a pig train including a leading seal pig, a supply liquid slug, a first isolation tool, a test liquid slug and a second isolation tool; permitting the train to traverse the pipeline interior by the force of fluid flow until the lead isolation tool is forwardly of and the second isolation tool is rearwardly of the selected selection of the pipeline; securing the position of the pig train by applying exteriorly of the pipeline appropriate signals to actuate the isolation tools to each engage and seal the interior of the pipeline trapping the test liquid slug therebetween; and pumping liquid from the supply liquid slugs into the test liquid slug to a hydrostatic testing pressure. In addition to testing, the pipeline can be repaired by moving the pig train into position where a defective area can be isolated by additional isolation tools.