Back in the times of the California gold rush, people didn't need to work out how to invest in the bonanza. They simply grabbed some basic mining gear and headed up into the hills.
Today California is the home of yet another wealth-creating boom - the oil contained within the Monterey Shale formation.
As Mark Twain once said, "History does not repeat itself, but it does rhyme."
The 1,750-square mile Monterey Shale formation covers much the same region that lured people from across the country hoping to strike it rich in the gold rush.
But this time it is oil companies looking for pay dirt, and the early signs are promising.
The Energy Information Administration (EIA) says the Monterey holds at least 15 billion barrels of recoverable oil, using currently existing technology. That's twice as much as either the Bakken or the Eagle Ford formations.
But even that estimate may be far too low...
Monterey Shale Is a Middle East-Sized Bounty
Cambridge Energy Research Associates thinks there may be up to 400 billion barrels of shale oil in the Monterey formation.
That's about half the amount of conventional oil in Saudi Arabia!
There's just one problem. . .California's convoluted geology.
The Monterey formation is just a jumbled mess of folds, faults, and broken and fractured rock. This makes it difficult to use the hydraulic fracturing and horizontal drilling techniques that have been so successful in unlocking the resources trapped in other shale formations across the country.
So even though California recently passed legislation not banning fracking, in the case of Monterey that may not matter. The oil companies need a way to "unlock" the oil lying in the formation.
So they are considering another, perhaps even more controversial, way to get the oil from the Monterey shale - acidizing.
In this process acids - hydrofloric and hydrochloric - are pumped into vertical wells to open passageways in the convoluted rocks, releasing the oil to flow to the surface through the well.
Acidizing is not new. It has been used from time to time for more than a century to dissolve debris around new wells and remove hydrocarbon deposits around old wells.
Chris Faulkner, chief executive officer (CEO) of Breitling Oil and Gas, told the San Francisco Chronicle that he believes the Monterey will not require fracking. He said, "acidizing will be enough to open up the rock. I think it could be a way to unlock the Monterey."
Still, the very difficult geology has dissuaded many oil companies from tackling the Monterey.
"I think the jury's out a little bit on the Monterey Shale," Chevron (NYSE: CVX) CEO John Watson told shareholders in May. Needless to say, Chevron is putting its investment dollars elsewhere for now.
But one firm is going full speed ahead into the Monterey...