Innovative monitoring of offshore methane and hydrocarbons with miniature sensors and autonomy

Autonomous Underwater Vehicles (AUVs) can be loaded with chemical sensors and sent on missions to conduct high-resolution surveys in the deep sea. They are of interest to the oil and gas industry, as, if fitted with the right sensors, they can be used to help monitor subsea pipelines for leaks and also pinpoint new hydrocarbon reserves under the seafloor by measuring the chemical composition (e.g. the dissolved methane concentration) of the waters above. However, AUVs are prohibitively expensive for routine monitoring and exploration, and often require a large and expensive ship to be present on the surface. A new innovation in AUV technology is the microsub. These miniature AUVs can cost about 2% of the price of a traditional large AUV and are small enough to be launched from a small inflatable boat or the shoreline. They can reach complex areas (shallow waters and reefs) that larger AUVs cannot get to, and can operate in large swarms to efficiently survey a large area. The main drawback of microsubs is that they have limited onboard space and power, meaning that many sensor systems cannot be carried. This means the measurements performed by microsubs are very basic. No methane sensors are currently available that can be deployed on microsubs. At the National Oceanography Centre in Southampton, we have developed a new miniaturised methane sensor that could be deployed on microsubs. In this project, we will adapt this sensor to be deployed on ecoSUB, a microsub developed at the NOC in partnership with Planet Ocean. We will work with BP to test the ecoSUB equipped with the methane sensor on demonstration missions, and help BP to change the way in which they perform leak detection and exploration. Detecting leaks early using microsubs will help BP reduce the cost and environmental impact of subsea pipeline leaks. More efficient exploration will reduce the cost environmental impact of searching for new oil and gas reserves.

The main output of this project (low-cost methane-sensor equipped microsubs) will change the way in which project partners BP and Chevron (and the wider oil and gas sector), as well as monitoring organisations such as project partner Blue Ocean Monitoring, can perform exploration and leak detection. Once this new tool has been demonstrated and optimised via the validation mission and stakeholder case study conducted as part of this project, BP and Chevron's exploration and leak detection teams will be able to re-assess automated monitoring and survey strategies. The low-cost nature of ecoSUB means that approximately 50 microsubs could be purchased for the price of a single full-size AUV. Once equipped with methane sensing technology, large fleets of ecoSUB units can be tasked with monitoring survey areas or subsea pipelines in a time-efficient manner. Each ecoSUB unit can send data and receive new commands via satellite when it surfaces, allowing data-driven real-time mission planning. Early detection of subsea pipline leaks is essential not only due to the significant costs associated with product loss and repairs, but also due to potential environmental and human health impacts. ecoSUB also has the ability to go dormant, and will be able to wait for the low power methane sensor to detect elevated levels before continuing an inspection mission. This will allow rapid leak or spill detection, leading to fast implementation of mitigation measures. With large fleets of methane sensor-equipped microsubs, the oil and gas industry will not require the presence of expensive surface vessels and significant personnel for monitoring applications.

Project partners will receive early access to this technology by being involved in the trials conducted through this project. Planet Ocean, who manufacture ecoSUB, will be able to promote ecoSUB as a CH4 sensor-enabled monitoring tool, which is unprecedented for a microsub.