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.
Steven Geiger 
Mitchell Beer 
one way of mitigating this rise in emissions with mature oilfields is to use solar EOR. This allows zero-carbon steam to be placed in mature oilfields and continue to extract more oil with no significant increase in emissions. And solar steam can be done equal or less than the price of natural gas, for example <$3/mmbtu in California oilfields which generate millions of tons of CO2 every year burning 17% of all natural gas in California.
I.e. large-scale decarbonization of the oil industry for free. Yes, you heard that right, for free.
If you're interested in learning more, here is a good summary of solar EOR real-life applications: https://www.slideshare.net/ssslg/solar-eor-enhanced-oil-recovery-myth-and-reality-75899608
Except that…at some point, that “decarbonized” oil you’ve extracted gets sent to an end point, and at that end point, it gets burned. That’s the point of the exercise. Even if the tar sands/oil sands could completely eliminate production emissions — and still compete against $40/barrel oil, $0.02/kilowatt-hour renewables, and plummeting battery and EV costs — at some point, the purpose of using solar to extract more oil from old oil fields is still to pump more carbon into the atmosphere. How can that ever work in the real world?