Remote Pig Position Detection via Hydraulic Transients
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Solution Overview
Problem
Existing systems for detecting the position of pig devices inside high-pressure fluid pipelines require numerous costly measurement stations and special pig devices with active sources, and are ineffective when the device is stuck or moving intermittently.
Innovation Solution
A method and system using sound sensors at pipeline ends to measure hydraulic transients caused by the pig device's stoppage, generating stationary waves whose periods indicate the device's position, allowing remote detection without complex stations or special devices, and functioning even when the device is stuck or moving intermittently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If numerous measurement stations are placed along the pipeline to obtain good accuracy in identifying the position of the pig device, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The invention extracts the measurement function from multiple distributed stations and concentrates it at a single endpoint. Instead of placing numerous measurement stations along the pipeline, the system uses a single endpoint measurement station that detects hydraulic transients propagating through the fluid, thereby achieving position identification without the complexity of multiple stations.
Solution Approach 2:
The invention introduces hydraulic transients as an intermediary carrier of position information. The pig device generates hydraulic transients when it moves or stops, and these transients propagate through the fluid to the endpoint measurement station, serving as a mediator that conveys position data without requiring direct measurement at the pig's location.
2Device complexity
If passive measurements like vibrations generated by the pig device are used for locating, then device complexity is reduced, but reliability deteriorates when the pig device is blocked
Solution Approach 1:
The invention transitions from measuring static or continuous vibrations to detecting dynamic hydraulic transients. When the pig device is blocked, it still generates hydraulic transients due to pressure changes and fluid dynamics, which can be detected by the endpoint measurement station. This dynamic measurement approach maintains reliability even when the pig is stationary or blocked.
Solution Approach 2:
The invention uses hydraulic transients propagating through the fluid in the pipeline as the measurement mechanism. Instead of relying on mechanical vibrations of the pig device itself, the system detects pressure waves and hydraulic transients in the fluid, which continue to occur even when the pig is blocked, thereby maintaining detection capability without additional complexity.
3Measurement precision
If an active source on board the pig device is used for location, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The invention makes the pig device self-sufficient for generating measurement signals. Instead of requiring external active sources mounted on the pig, the system utilizes the pig's own movement and stopping actions to generate hydraulic transients in the fluid. The pig device itself serves as the source of measurement information through its interaction with the fluid, eliminating the need for additional onboard equipment.
Solution Approach 2:
The invention changes the measurement parameter from direct mechanical or electromagnetic signals to hydraulic transient characteristics. By monitoring changes in pressure wave propagation, reflection, and attenuation, the system achieves position detection accuracy without requiring the pig device to carry active sources. The measurement relies on changes in fluid dynamics parameters rather than signals from the pig 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
Enables accurate, cost-effective remote detection of pig device position along long pipelines, including when the device is stationary or moving intermittently, without the need for extensive measurement stations or special equipment, with detection distances reaching up to 30 km using commercial instrumentation.
Implementation Method 1
A method and a system are disclosed that use the measurement of the hydraulic transients produced by the stoppage of the pig device
Implementation Method 2
sound sensors positioned at at least one end of the pipeline measure the sound signals produced by the pig device during its movement
Implementation Method 3
generating stationary waves whose periods indicate the device's position
Data Source
AI summary
A method and a system remotely detect the position of a pig device inside a pipeline for transporting pressurized fluids, like for example long distance oil and gas pipelines having a strategic international value. The method foresees equipping the pipeline with pressure sensors in contact with the fluid, located at at least one of the two terminals of the pipeline, and the sending and processing of signals by a control unit. The operation of the system is that of identifying and locating, in real time and continuously, a pig device that moves intermittently inside the pipeline, for example during cleaning, monitoring, measurement and non-destructive control operations.