The energy cost and carbon intensity of operating aging, giant oil fields can rise dramatically as extraction rates begin to fall, according to a new study in the journal Nature Climate Change.
That reality means decision-makers and industry managers may be underestimating the climate impact of fossil production, particularly from fields that have already given up more than a billion barrels of oil, CleanTechnica notes.
“Current climate and energy system models typically don’t explore the impacts of oil reservoir depletion in any detail,” said co-author Adam Brandt of the Stanford University School of Earth, Energy and Environmental Sciences. “As oilfields run low, emissions per unit of oil increase. This should be accounted for in future modelling efforts.”
CleanTechnica notes that modellers usually estimate greenhouse gas emissions from fossil production by reverse engineering them from the economic value of different extraction products—oil, gas, and other petroleum products. But “this top-down approach for converting economic values into environmental and energetic costs misses a lot of underlying information,” warned Stanford post-doctoral researcher Mohammad Masnadi.
“What’s more, many studies look at data from only a single point in time, and as a result capture only a snapshot of an oilfield’s greenhouse gas emissions,” the Stanford team noted in a release this week. “In order to paint the most accurate picture of an oilfield’s true climate impacts—and also have the best chance of reducing those impacts—it’s necessary to assess the energy costs associated with every stage of the petroleum production process, and to do so for the oilfield’s entire lifetime.”
The release notes that “most oil companies are reluctant to release this type of temporal data about their oilfields. The Stanford researchers developed two workarounds to this problem.” They “gathered data from places where transparency laws require oil production data be made publically available,” including Canada, Norway, the UK, and California. They also surveyed the scientific literature for any published clues to oilfield production levels.