Fugitive methane emissions are an often-invisible consequence of fossil fuel production, and pose serious challenges to the oil and gas industry in their monitoring and mitigation.
For the oil and gas sector to take effective action, emissions must first be measured, yet no feasible technology can track all methane losses.
Methane is produced at virtually every oil and gas project around the world, either as a by-product of oil production or directly from gas or gas condensate reservoirs.
While the vast majority of methane produced is sold as natural gas, when emissions are directly released into the atmosphere it can lead to substantial impacts on global warming.
However, regulations and penalties for methane emissions are expected to increase, with Wood Mackenzie noting the goals of the upcoming COP28 climate conference are likely to include more ambitious binding country commitments to methane reduction.
Methane emissions can be classified into two broad categories, according to a report by Wood Mackenzie: snowballers, which are minor but innumerable; and super-emitters, which are few by comparison but of very large scale.
The authors said: “Both can be intentional or accidental, but while super-emitters catch the headlines, snowballers add up to a large cumulative impact.
“Existing technology is unable to provide complete coverage or granularity on methane losses – even the most proactive oil and gas companies probably still underestimate the true extent of avoidable methane losses, making a better emissions measurement option to support mitigation even more urgent.”
There are six main monitoring approaches upstream operators currently use to measure emissions, which are all made more difficult by the remote locations and scale of operations.
These approaches are satellites, aircraft, drones, regional sensors, point sensors, and most commonly, optical gas imaging (OGI) cameras.
Though not as prevalent in the atmosphere as carbon dioxide, methane is 86 times more potent and is responsible for almost a third of emissions-induced increases in temperature since the start of the industrial era.
The expanded edition of the International Energy Agency’s (IEA) Global Methane Tracker, which includes coal mines and bioenergy for the first time, estimated the energy industry’s share of all methane emissions from human activity to be about 40 per cent.
The IEA has also found global methane emissions from the energy sector were about 70 per cent greater than officially reported by national governments.
These emissions include large-scale flaring and venting (where operators have no access to gas infrastructure and markets), but also routine methane losses from many small, undetected or unreported leaks across the oil and gas supply chain.
The scale of methane emissions worldwide was further confirmed earlier this year, with research by the Laboratory of Climate and Environmental Sciences in France quantifying the most abundant methane emissions released into the atmosphere by the global hydrocarbon sector.
Using thousands of satellite images captured over two years, the researchers systematically mapped 1,800 methane plumes across the globe, 1,200 of which were attributed to the exploitation of hydrocarbons.
The plumes were comparable in climate impact to 20 million cars being used over a year, and likely represented only about 10 per cent of actual emissions.
Importantly, the study demonstrated the massive methane releases were not random and chaotic, but detected systematically above certain oil and gas extraction sites.
Introducing reliable atmospheric monitoring systems would enable systematic monitoring, according to the researchers, and help assess the impact of local measures aimed at reducing emissions.
The majority of methane emissions in Australia come from the agricultural and natural gas industries, with fugitive emissions from oil and gas production estimated to be about 6 per cent of Australia’s emissions, compared to 13 per cent globally.
While oil and gas majors have pledged to significantly reduce their methane emissions, QLM Technology chief executive Murray Reed noted what isn’t measured cannot be managed, and no one is measuring methane properly, continuously, and at scale.
Reed said: “The scale of the problem is enormous, with more than half a million active gas wells in North America alone, and many thousands of offshore rigs and gas storage facilities worldwide.
“In the UK we have 24 major pipeline compressor stations, which power long-distance natural gas pipes, and hundreds of above ground storage installations.
“All are leaking at some time.”
Royal Dutch Shell plc has set a target to maintain its methane emissions intensity below 0.2 per cent by 2025, covering all assets for which Shell is operator, using a broad range of leak detection methods and technologies such as optical gas imaging (OGI) cameras.
BP has also set a stringent target to maintain emissions at 0.2 per cent, as well as announcing in 2019 an industry-first, continuous methane measurement program for all its new oil and gas projects.
Technologies involved with this monitoring include gas cloud imaging, drones that live stream data to advanced on-board sensors, smart glasses for field operators using augmented reality, and handheld gas leak detectors.
ExxonMobil has targeted 15 per cent reductions across the entire company, as well as initiated an industry-academia collaboration to develop an innovative sensor network that continuously monitors methane emissions across large areas.
This type of high-frequency monitoring system would enable operators to more efficiently direct repair and maintenance resources to specific locations.
