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The engineering behind the US Strategic Petroleum Reserve

The engineering behind the US Strategic Petroleum Reserve

johnjwang

Comments (53)

  • anigbrowl
    Salt contains the oil and helps seal small fractures. The rock salt surrounding the SPR’s caverns has extremely low permeability, meaning fluids have very little ability to pass through it. It also doesn’t react with petroleum. Under enormous pressures underground, salt also slowly deforms, which helps close small fractures. The salt itself can therefore contain the oil without a steel-and-concrete tank lining the cavern.Oil floats on water, which means pumping water into the bottom of the cavern pushes the oil out. As fresh water is pumped into the bottom of the cavern, the oil gets displaced upwards into a delivery system.The more water you pump in, the lower the quality of the oil that's pumped out; we are basically loaning the oil refiners money to buy SPR oil they don't really want. Also, the more water we pump in, the more salt leeches into the water and the more the bottom of the chamber deforms, creating shear forces in the upp walls that lower its overall structural integrity.I've posted this before; it's a recent report on the status and maintenance of SPR facilities, which is very clearly written and well worth your time if you want to understand the topic better: https://www.gao.gov/products/gao-26-106918
  • kulahan
    I’m certain engineers have considered this, but it doesn’t seem answered anywhere: why not just pump the original brine back in to move around the oil? Wouldn’t that at least prevent eroding the storage unit and causing it to fail?Unrelated: dang, he wasn’t underselling this being a pretty elegant solution! I never would’ve thought of it, for sure.
  • Ellis_dev
    Makes you appreciate the physical infrastructure challenges, not just software. Bet the data logging and monitoring systems are ancient but robust.
  • LPisGood
    One fun fact I’ve heard is that the strategic oil reserve requires like 100-150 million barrels of oil to maintain operational pressure and even be functional. This means we can’t draw it down to zero; not even close.
  • rafaelc
  • zachlatta
    This is so incredibly interesting and one of the best things I’ve seen on HN recently. Thank you for the awesome post!
  • hankbond
    Very cool, big fan of these bite size explainers. Has there been more cycling recently? Are the sizes of the caverns tracked anywhere?
  • sklargh
    Well worth your time if you are interested in a more detailed discussion https://www.construction-physics.com/p/how-the-strategic-pet...
  • analog31
    An interesting aside is that the process for making these salt domes is also used for mining salt. Drill a hole, pump water down, and up comes brine. The brine can be used as a chemical feedstock, e.g., for production of things like chlorine, sodium hydroxide (lye), and sodium carbonate for glass.
  • metrix
    What do they do with the brine when they fill it back up with oil?And do they use fresh water?
  • ivraatiems
    How long does the crude last uner these conditions? Refined oil products like gas have pretty limited shelf lives (I think 6-12 months for gas).
  • calmlynarczyk
    This is a pretty popular topic this past month, huh?https://www.construction-physics.com/p/how-the-strategic-pet...
  • cyberax
    One thing about salt domes: they almost by definition are surrounded by very low-permeability dry soils. Because otherwise they would have dissolved long ago!And a related way to use salt domes is for natural gas storage.
  • redwood
    Dumb question but why not pump it back into where it was pulled from.. or just leave it in a a reserve paid for by the gov
  • hiring_signals
    [flagged]
  • recursivegirth
    [flagged]