Co.L.Mar is a specialist provider of acoustic subsea leak detection equipment.

The company has been operating in the marine industry since 1982 and is experienced in acoustic engineering and geophysical investigations. Co.L.Mar is certified ISO 9000 – 2015.

Subsea leak detection systems for pipelines and subsea installations

Co.L.Mar. has released an acoustic subsea leak detection system ALD® (acoustic leak detector) which is able to locate very small leaks on the sea line even in extremely hard environmental conditions. After the first leak detection, back in 1998, the technology and the relative service have been developed for many years and an international patent has been obtained.

It is currently one of the fastest, most accurate and reliable methods for sea line leak inspection, especially when an emergency occurs. We are an international leader in this specialist area thanks to our decades of experience and history of delivering proven leak-detection solutions.

Subsea leak detection by diver on a flange.
Subsea inspection of an underwater structure.
Co.L.Mar provides acoustic subsea leak detection equipment and noise assessment services for offshore pipeline applications.
AUV is a perfect platform for ALD inspections, due to smaller cost and high-sensitivity.
ALD equipment: surface unit and subsea bottle.
Layout of the ALM system: subsea sensor and surface receiver.
The Acoustic Leak Detection (ALD) captures acoustic data as it scans the pipeline. The acoustic data is transferred to an onboard PC, where it can be processed in real time, then displayed and digitally recorded.
Other subsea leak detection methods are less effective than the ALD at locating leaks in demanding conditions, such as minimal visibility and strong currents.
Our subsea leak detection equipment can be rapidly deployed on small support vessels by our acoustic engineers.
The company delivers underwater noise assessment services that use our proprietary acoustic leak detection equipment.

Since 2017, the ALD®  technology has been qualified by DNV “for locating leaks in subsea pipelines and installations”.

In the many offshore inspection projects we have worked on worldwide, we have been able to detect leaks as small as 0.04lt/minute.

Underwater pipeline leak inspection

The ALD® underwater pipeline leak detection system features an underwater sensor that collects acoustic data as it scans the pipeline. The acoustic data is transferred online to an onboard receiver, then to a PC where is analysed, displayed and recorded by proprietary software.

Compared with other leak detection techniques, ALD® has the following advantages:

  • Not affected by current, turbidity or pipeline burial
  • No need to stop production
  • High sensitivity for small leak detection
  • Reliability: as of May 2015, 100% rate of success
  • Rapidity: fast mobilisation worldwide
  • Zero environmental impact
  • ROV, TOWED, DIVER, AUV inspection modes available
  • We served SAIPEM, ExxonMobil, McDermott, SHELL, BP, PETRONAS, TOTAL, TECHNIP, BJ Services, FUGRO and HORIZON

Underwater leak detection and inspection techniques

During years of development, different underwater leak detection and inspection techniques have been defined:

  • ROV inspection – the sensor is installed on the vehicle which follows the line at a speed of about 0.7kts
  • TOWED FISH – the sensor, in a ‘fish’ configuration, is towed by a vessel along the pipeline track
  • DIVER – the handheld sensor configuration is driven by a diver (suitable for flange inspections)
  • AUV – a special version of ALD® can be easily fitted into any AUV payload
  • VERTICAL DEPLOYMENT – the sensor is lowered from the boat in a line kept vertically by ballasts

Additional sensors integrated into the main system are available depending on the cases:

  • Dye detectors
  • Hydrocarbon detectors
  • Methane detector
  • Bubble detectors

25 years experience in subsea leak detection

Colmar is probably the company that has detected the largest number of leaks in subsea installation, in 2023 thus number reached the value of 60. This is very large considering how rare is a leak event.

We have detected leaks worldwide, from the Caspian Sea to Borneo, from the USA to China and West Africa. We have been working under the ice or over 2.000m depth.

We have detected leaks on many different structures including:

  • Oil, water and gas pipelines
  • Hydraulic circuits
  • FJ weld, longitudinal weld
  • Buried pipelines
  • Flanges
  • Valves
  • Umbilicals
  • Umbilical connectors
  • Riser
  • Clamps
  • Wellhead

ALD® as leak contingency plan during hydrotest

During the hydrotest of subsea installation, a leak contingency plan has to be put in place. This traditionally consists in injecting fluorescine or other kinds of dye and then proceeding with a visual inspection if required.

But in this case, very often the visual inspection fails because leaks on new installations are typically very small (FJ solder crack or leaking flange) and spotting any sign of dye became impossible. Not to mention if visibility is poor or some current burial is present. As a consequence, we are often called out on a very urgent base after the failure of the hydrotest of the traditional visual inspection.

For this reason, many clients contract us to standby on-site during any hydrotest so that, with a small cost they can have the best leak detection service guaranteed in case of need.

Also, dyes are pollutants and in many areas of the world are interdicted, while ALD has zero environmental impact.

So we can provide a more effective and environmentally friendly leak contingency plan during pre-commissioning.

ALM acoustic leak monitoring of subsea installation

On the base of the experience gained in subsea leak inspection, we have recently developed a system for permanent monitoring of the most critical areas of subsea installation: manifolds, wellheads, valves, etc.

The system is composed of one of the more intelligent sensors to be installed subsea and of a surface station for settings and alarm generation. The subsea units are designed for a 25-year life expectancy with no maintenance and an operating depth of 3,500m.