Why would it need to be climate controlled or lighted at all? And making concrete impermeable to petroleum and in ginormous quantities sounds like a major engineering and construction challenge.
Salt is impermeable to petroleum. Along the Gulf Coast, that’s often how the petroleum we extracted was trapped for millions of years. Salt caverns are already nature’s way of storing it for long periods of time.
Ever hear of Avery Island? Where the Tabasco peppers were grown and Tabasco sauce was originally created? The “island” is a giant underground salt dome. And, like many salt domes in that part of the world, it trapped commercial quantities of petroleum that we have subsequently tapped.
Spindletop was another well known salt dome that produced commercial quantities of petroleum. Most of the major discoveries out of the Gulf of Mexico likewise are found beneath impermeable (to petroleum) salt.
Around April of 2020 the Strategic Petroleum Reserve was at about 90% capacity. That still left room for another 77 million barrels more or less. It’s seems to me to be a real shame that our government failed to take advantage of the ridiculously low prices at the time.
I think Great_Antibob summed it all up quite well when he said, “… [It’s] more about politics rather than economics. Or rather, they’ve almost always been more about politics. …”
Since there has been all this talk about barrels of oil, I would like to take this opportunity to point out that “barrel of oil (bbl)” is strictly a unit of measurement. A barrel of oil is defined as exactly 42 U.S. gallons. Very few, if any, barrels with a capacity of 42 gallons actually exist. All of the big steel and plastic drums you see on TV, on the Internet, driving around town, etc. are 55-gallon drums.
More than that, a lot of the crude oil we extract in the US tends to be light, sweet crude but, for reasons, our refining capacity is mainly geared towards heavy, sulfurous crude. It’s not exactly fungible. Economics is weird a lot of the time.
We could try to store refined products, instead, but some types are harder to store than crude, and, worse, some refined products can’t be stored indefinitely without degrading.
In hindsight it makes sense, but it wasn’t a huge loss. The US was going to pay $3b or $39/bbl for the 77m capacity. Instead the US leased out 23m of the 77m capacity to the oil producers.
In the end, the US made money from the leases instead of adding to the national debt.
The devil is certainly in the details. In 2015, Congress passed a law to periodically sell oil from the SRP to fund improvements to the SRP.
When the Biden admin sold 180m bbl after Ukraine was invaded, only 59m bbl were replaced. Instead, 140m bbl of planned sales were cancelled.
So part of the reason for lower SRP levels is due to the scheduled sales. Coincidentally, since oil prices were so high after the Ukraine invasion, the planned sales effectively made more money than expected.
Even the layman’s version is complicated enough that you could blame either party.
Yeah, I didn’t want to get into the details but that’s the main reason. The US more than most countries specializes in heavier, sour crude, which requires a bit more engineering. Equipment can be refitted but it’s an expensive process and shipping different grades of crude can be cheaper. As I noted, economics be weird sometimes.
From querying Google Gemini, Venezuela is exporting 0.7 - 1.25m barrels/day while the Hormuz closure is blocking 6 - 11m barrels/day. I didn’t double-check those numbers, but if true, Venezuela is a drop in the bucket (barrel?).
It isn’t quite correct to say salt caverns are natures way of trapping oil.
The salt caverns of the SPR are man made by solution mining tall caverns out of the salt body, then filling them with oil. The oil is displaced out of the cavern by pumping fresh water into the bottom and the oil
Is pushed out the top. It is very unlikely that there is any empty space in the caverns as fluid is needed to provide hydrostatic balance to stop the cavern collapsing.
When it comes to oil reservoirs around salt domes , they are most definitely not caverns in the salt dome.
The salt dome , which more looks like a big pillar of salt rising though the formations, pushes up through sedimentary layers of rock and displaces and deforms the rock and forms structural traps which also need some sort of cap rock / seal to seal those traps. Oil and gas then migrates up into those traps. The salt dome itself is probably not taking part in any sealing of the trap. The rocks butted up against the salt tend to be fractured and not at all what you need for a seal and the oil and gas would just migrate up and away. Often when drilling through a salt dome to get to the formations you want , the exit from the salt is fraught with fluid losses, well bore collapse and other comedy.
A paper here from sandia about how the spr caverns were made with some sonar images showing the shapes of the caverns at one spr site, in case anyone wants to see what the caverns look like.
I found a subtle distinction I’d missed before. The drawdown contracts will be finalized by early September, but the actual fulfillment won’t be complete until probably the end of October. In terms of the effect on gas prices, it seems like that doesn’t really matter, but for the physical infrastructure, it does delay whatever damage is going to be caused.