Neptune Oceanographics Ltd is a global leader in providing detection services for subsea pipeline leaks in the offshore oil and gas industry. Its strong emphasis on its research and design (R&D) programme ensures that methods for uncovering subsea leaks are continually developed, and mastered.
In fact, Neptune's dynamic R&D techniques not only deliver successful detection practices, but also result in cost-effective solutions whose environmental impact is minimal. Its technical advances in the field are significant and ongoing; in addition to subsea pipelines, Neptune is also an expert in discovering leaks from risers and control systems.
The company operates from the UK with agents in several strategic international locations. With facilities in Norway, Brazil, UAE, Australia, Houston and Singapore, equipment is ready for immediate deployment to anywhere in the world at very short notice.
Furthermore, its experienced engineers and operators accompany the equipment to the offshore site. By doing so, their expertise is available for onboard mobilisation and operational instruction. If required, they can also stay onboard and direct the leak detection survey.
Neptune Oceanographic implements a variety of methods for tracing subsea leaks. However, its long-range fluorescence and passive acoustics are most popularly used. Other areas of expertise include temperature, methane, and hydrocarbon detection.
Neptune's fluorescence detector system is comprised of a collection of long-range submersible fluorometers. Their refined sensitivity means that they can pick up leak detection dyes and liquid hydrocarbons that are at concentrations so low, that they're imperceptible to the naked eye.
This level of functionality is maintained in turbid conditions with high spatial coverage, and further demonstrates the advantages of Neptune's fluorescence detector system.
The company also makes sure to comply with the latest legislation in regards to dyes that are discharged at sea. This effort is important in the application of subsea control systems or hydrostatic pressure testing. Neptune Oceanographics can detect all leak tracers that are in use today such as Roemex's red dyes, UV clear dyes, etc., and Fluorescein, the most common of dyes, that is being phased out as it is no longer in accordance with current legislation in many parts of the world.
Directional Hydrophones for Passive Acoustics
Hydrophones can be described as underwater microphones that register the ultrasound of fluids leaking under pressure. Neptune Oceanographics' acoustic leak detection sensor incorporates the use of a directional hydrophone, which filters out frequencies caused by surrounding vessels, and the attending ROV.
Neptune additionally administers the use of sophisticated software and sensors that are necessary to screen out intruding ambient noise. For example, the acoustic frequencies of small leaks are similar to other noises that are well above the audible range. Therefore, Neptune's acoustic leak detection sensor sieves out any input from interfering elements. It's tuned to respond to a range of frequencies emitted by high-pressure leaks through small apertures.
Due to its versatility, the sensor can either be mounted on a remotely operated vehicle (ROV), autonomous underwater vehicle (AUV), or pipeline inspection gauge (PIG). It can also be diver-held.
Typical applications involve detecting gas leaks from subsea installations, and locating fluid leaks from buried pipelines, and those within pipe configurations.
Differential Temperature Measurements
Under some circumstances such as with water injection flowlines, leaks can be identified using the temperature difference between the surrounding seawater and the water leaking from the flowline. The flowline water temperature is normally above ambient seawater temperature due to the high pressure pumping required. Neptune has developed a differential temperature technique that not only detects very small seawater temperature changes close to a leak but can also be deployed on the pipe wall to measure temperatures of the pipeline surface.
To do so, it utilises a rapid, high precision thermistor in its thermal leak detector. The thermally sensitive resistor is connected through the detection system to the ROV umbilical for onboard display and recording.
Detection of Hydrocarbons
The offshore oil and gas industry recognises hydrocarbons as roughly falling into the categories of oil, gas, or a mixture of both (multi-phase). Hydrocarbon leak detection depends on an assessment as to which of the compounds is prevalent.
Hydrocarbons in liquid form such as crude oil can be detected using Neptune's long-range fluorometers. For gas however, Neptune deploys SNIFFIT, a sensor applied primarily for the discovery of methane leaks. However, its functionality also includes direct detection of all gaseous hydrocarbons.
SNIFFIT is an essential tool in the offshore oil and gas environment for the detection gaseous leaks from pipelines and other subsea installations. The system is simple to operate, and is designed for easy fitting aboard ROVs, AUVs and other underwater vehicles. Measurements are also made directly by SNIFFIT.
Neptune Oceanographics Ltd
Sapharey House, Sturt Road
Charlbury, Oxon OX7 3SX
Tel: +44 (0)8453 707177
Fax: +44 (0)8704 581979