Pipeline networks are generally utilized to transfer various fluids, oil, and gases across large distances. Pipelines are considered the most secure, reliable, and powerful methods to transmit these substances.
If a pipeline isn’t well maintained, especially adjacent to the construction joints, low spots that trap moisture, and fault-prone areas, which could result in serious damage.
Having a relevant monitoring system can help to protect your assets and reduce potential risks before they become severe.
In this blog, let’s learn more about leak detection and its role in maintaining the health of pipelines.
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What is the Leak Detection Technique?
The process of determining if a leak has occurred in a system that contains fluid, liquid, or gases is known as leak detection.
Popularly known as LDS, Leak Detection Systems are designed to help the pipeline controllers in the localization and detection of leaks.
To support the process of leak detection, LDS provides alarms and related notifications to the pipeline controllers.
Identification of leakage concerning the size, depth, composition, burial, or substance needs an effective detection device.
Pipeline leak detection can improve the reliability of the system while minimizing downtime and inspection time.
Most Used Leak Detection Methods
Internally-based and externally-based LDS systems are the two major categories of Leak Detection Systems.
The internally-based systems analyze the internal pipeline characteristics with the field instrumentation sensors that detect flow, pressure, and fluid temperature.
Externally-based systems utilize various sets of field instrumentation to analyze the external parameters of pipelines like thermal cameras, infrared radiometers, acoustic mics, vapour sensors, fibre optic cables, etc.
The techniques to detect leaks vary depending on the kind of pipeline used and the substance it transports.
Let’s take a glance at some of the major leak detection methods used in the gas, oil, and petroleum industries:
1. Acoustic Monitoring Technique
Most acoustic sensors depend on the differences in patterns of background noise to implement leak detection.
These sensors are held outside the pipeline to detect leakage through measurements of noise levels at every point of the network.
This data is further utilized to produce the noise profile of the pipeline. The alerts on leaks are generated once the noise profiles deviate from the baseline.
Acoustic sensors are placed in the pipeline or connected to the pipe for underground lines with steel rods.
A larger number of acoustic sensors is essential to track the longer pipes.
2. Gas Sampling Method
Detection of methane or ethane in the gas sampling techniques is done using a flame ionization detector within a probe, which is either vehicle mounted or portable.
Gas sampling methods are beneficial since they are highly sensitive to lower gas concentrations.
As a consequence, you can analyze even the smallest leakages with gas sampling procedures. Since this approach is very accurate, there are least chances of false alarms.
3. Digital Oil leak detection
Shielding the semi-permeable conductors with a permeable and insulated moulded braid helps to protect the digital sensing cables.
Once an electrical signal passes through the internal conductors of the cable connector, this is further monitored with a microcontroller embedded inside a connector.
The excess fluids move along the outer permeable braid and establish contact with the inner semi-permeable conductors.
As a result, the microprocessor detects a change in the electrical characteristics of the cable.
Thus, the microprocessor can analyze the fluid along the 1-meter resolution length and sends signals to the operators or monitoring systems.
Thus the sensing cables can be enclosed around the pipes, buried in the underground pipelines, or managed as a pipe-in-pipe system.
4. Infrared Radio System Pipeline Testing
IR thermographic pipeline testing has been well-known as an accurate and effective method used to detect and analyze various pipeline defects.
These include pipeline leaks, deteriorating pipeline insulation, erosion voids, poor backfill, and so on.
The infrared video cameras that use customized filters can detect gas leakages up to a specified range of IR wavelengths.
The spectrum thus facilitates the absorption of infrared radiation that is absorbed by hydrocarbons.
This lets the detection of leaks on the video display in the form of smoke images.
As the thermal conductivity of wet ground changes compared to that of dry ground, Infrared cameras are also helpful to detect liquid leaks.
In such a scenario, the pattern of temperature above the location of the leak is different.
5. Fibre-optic leak detection
Fibre optic cables can monitor the leaks outside the pipes probably caused by the physical changes that occur in the leak location.
The shift in temperature profile is one of the most frequent physical alterations. To analyze the changes that occur in the pipeline, a fibre optic link is connected to it.
Further, the laser is used to emit pulses that molecules reflect along the fibre optic wire.
Determining the temperature at the point where a molecule and photon collides is made with the magnitude of the reflected laser.
A combination of the reflections creates the temperature profile, to let you test the unique temperature variation of the leak site.
Fibre optic cables can monitor pipeline leaks and pinpoint leaks, with essential attention to monitored systems during cable installation.
If the gas is being tracked, the cable needs to be kept above the pipeline since gas takes a natural rise.
In the case of liquids and fluids, it is wise to lay the cable beneath the pipeline.
6. RTTM Method
RTTM or Real Time Transient Model is defined as a real-time model that can simulate the system’s behaviour.
This Leak Detection System incorporates laws like momentum, mass and energy conservation, to draw mathematical models of flow in a pipeline.
Using mathematical algorithms, it determines the temperature, pressure and mass flow of any point in pipelines in real time.
It mimics two kinds of flow: steady flow and transient flow with the RTTM technology, and the leak rates are calculated with formulas.
Pipeline leaks can cause serious impacts including damage to the environment, challenges to human safety, damage to property and reputation, etc.
Nevertheless, it adds to the financial loss through additional clean-up costs and fines. The rapid detection of pipeline leaks is inevitable to avoid potential risks and reduce loss of the fluid, liquid, or gases that the pipelines transfer.
To improve efficiency and adhere to environmental commitments, LDS systems are essential. They detect the leaks promptly and precisely while functioning well under all operating conditions with sensors for high reliability.