The Monterey! Almost all of the oil in California comes from there. It is what we call a 'source rock' where enough organic material accumulated in the past, which then converts into oil after a process wherein the rock is buried, heated and pressurized to create petroleum (this is called diagenesis, catagenesis and metagenesis). Lots of that oil created in the Monterey Formation migrated into shallower reservoir rocks with good permeability which is easy to produce, that's why they have been pumping oil in Kern County and the general LA Basin for a century now. But the Monterey remains the ultimate prize, as technology has allowed us to now exploit source rocks instead of what we did in the past where only high-quality reservoir rocks were drilled.
![[Image: thousands-of-nodding-donkey-pumps-on-the...e1k0bn.jpg]](http://l7.alamy.com/zooms/a042a0f328a140959556ff4984320223/thousands-of-nodding-donkey-pumps-on-the-kern-river-oilfield-just-e1k0bn.jpg)
There is a simple reason why the Monterey hasn't caught on as the next big thing -- the geology is extremely complicated, and until the geology is figured out, engineers cannot implement completion strategies.
Geology: Most of the best American oil production lies to the east of the Rocky Mountains. Think of plays like the Bakken in MT and ND, the Niobrara (DJ Basin) in CO and the Powder River Basin in WY. They were generally deposited in simpler geologic settings. The Bakken was a tranquil and calm equatorial sea in a tropical latitude during the Carboniferous period (around 300 million years ago). The Permian Basin developed a bit later, also a simple, shallow marine environment at a low latitude. Meanwhile, all of that stuff directly east of the Rockies like the stuff in Wyoming and the Denver Basin formed after the Rocky Mountains came to be in the Cretaceous maybe 75 million years ago, where a big seaway stretched from Alberta to the Gulf of Mexico. The reason I mention all of this is to try to explain that most of these major oil fields were deposited in flat, shallower seas, and were gradually buried over time, with little in the way of subsequent mountain-building events to modify the formations into complex folded and faulted reservoirs.
California is NOT like these other places. California has some of the most spectacular and diverse geography on Earth - where else do you have coastal mountains, fertile inland valleys, deserts, basin and range topography, etc. Geologic processes create those, and you could easily teach multiple courses in any university geology program on the tectonic processes that created what we see in California today, and many Master's and PhD's have been written on the subject. What we need to know is that the Monterey formation was once a shallow, warm sea along the western margin of California in the modern Central Valley:
![[Image: calif_relief.gif]](http://www.sjvgeology.com/geology/groundwater/calif_relief.gif)
The Central Valley itself is bound to the east by the Sierra Nevada Mountains, which formed maybe 250 million years ago when the coastline of 'North America' was probably at the same longitude as Utah/Idaho today, as part of the Pangea supercontinent, and collided with an island arc to build that mountain range. Flash forward to 20 million years ago where we saw some crustal extensional activity with associated volcanism, and deep marine basins formed between San Fran and the O.C. The Monterey was deposited during this time, in this elongated basin. Five million years ago most of the tectonic activity along the west coast we know today was finished, including the Peninsular Mtns, Cascade Mtns, Transverse Ranges, the modern Sierra Nevadas, etc. So we have a Monterey formation in the Central Valley bound by mountain ranges to the east and west. Despite being a young formation, the Monterey has been worked through by some pretty active tectonic forces, it is actually really crazy how deep it is (up to 15,000 feet in some places) while having surface outcrops in other locations in the state:
![[Image: library---9132.jpg]](http://web.csulb.edu/~behl/MARS/files/library---9132.jpg)
From its initial deposition 17-20 million years ago to today, that is some rapid geological activity. To put it in perspective, the paleoproterozoic Canadian Shield rocks in Ontario and Quebec are up to 2 billion years old. It's a testament to the tectonic activity in California, with active subduction, rifting and rotational activity all in pretty recent geoloigic times. So keep that in mind when you think of drilling engineers trying to design a horizontal well through this formation: it is extremely folded and faulted, and would be very difficult to maintain a drill path through a consistent horizon. It's also just really expensive to drill wells this deep -- since the San Joaquin Basin is quite cold compared to basins east of the Rockies (likely due to the subduction of the cold oceanic plates proximal to California which acts as a heat scavenger), the 'oil window' (pressure/temperature conditions where the conversion of organic matter into petroleum occur) is much deeper, and it costs money to drill deep wells. That's why all of the shallower Kern River fields near Bakersfield have been in action for 100+ years -- oil is buoyant so it likes to migrate upwards, and if there is a pathway of permeable rocks for it to flow upward, it will. Most of these older Bakersfield wells are in fact exploiting Monterey-sourced oil, but it is oil that escaped to shallower rocks. With new technology, they think that they can get to the oil trapped at the source, but the depth and complex structure makes this difficult.
In addition to this complicated structural mess we see in the Monterey, we also have to understand the notion of heterogeneity. The common unconventional resources we see are generally one rock type. The Bakken is a dolomitic siltstone, the Powder River is all tight shaly sandstones, the Niobrara is chalk, and the Permian Basin stuff in TX is this muddy carbonate shit. They all present their own challenges, but are generally homogeneous in composition. The Monterey is, as you would expect, EXTREMELY varied in lithological composition. It is 2000 feet thick but a combination of sedimentation caused by erosion from nearby mountains, tectonic uplift, favorable conditions for micro-biological activity and fluctuating sea levels due to climate change have all helped contribute to the mess that is today. We have diatomaceous earth (which are the skeletal remains of microorganisms called Diatoms, a silica-based creature which leaves its fossilized remains on the sea floor when they die), Coccolithophores (the precursor to Chalks, a microorganism that has a calcitic skeletal framework), phosphates, cherts, turbidite clastics, muds (precursor to shale), silts, sandstone fingers, silica matrices, calcitic matrices, secondary dolomites... It is almost strange how they can label a rock formation this diverse as a single formation, but the changes are so sudden and frequent that they just call it all the Monterey because it was deposited in the same time period in a single region. As such, rock properties change, so there are different porosities, permeabilities, fluid saturations, oil composition, aquifer influence, etc, all in the same area. There is no such 'secret' to unleashing Monterey oil to the world, because there is so much variability in it.
Because the Monterey is such a geologically diverse formation, there will be exploitation methods that work in some areas, but not in others. I logged on to SPE (Society of Petroleum Engineers) database and found multiple papers with 'promising' results that would work in one small area but not in another. Like when you google "Cures for the Common Cold" and there are 50 different treatments (Vitamin C, sleep, steam room, chicken noodle soup, cuddling with a teddy bear, etc). If there are a ton of 'cures' instead of just one, maybe that means they haven't figured out a solution to the problem at all.
Here are some of the completion strategies being used right now in the Monterey:
-They have tried
Hydraulic Fracturing:: The image below is somewhat iconic in geological engineering circles:
![[Image: subsidencePole.jpg]](http://ca.water.usgs.gov/projects/central-valley/images/subsidencePole.jpg)
That is how much the ground surface has subsided in the last century due to the removal of groundwater in the San Joaquin Valley area in that California 'Inland Empire.' All due to agricultural irrigation. Think of the cultural significance of the Bakersfield-area farming industry, of those Merle Haggard '
Okies from Muskogee' to Steinbeck's
Of Mice and Men lore. The massive population increase in California combined with the exploitation of the water resource in a pretty irresponsible manner back then was bad, it's out of control now with the advent of the industrialized agriculture approach we see now. The water shortage in California is very real, and people are very aware of it. Hydraulic fracturing operations require billions of gallons of water, especially if you have to drill these massive 8,000 to 15,000 feet wells to exploit the deep Monterey Fm. Where the hell is that water going to come from in this environmentally sensitive area, especially if the companies face opposition from environmental groups? Some of the Monterey fractures beautifully, some of it is naturally fractured so secondary permeability is good enough to allow for oil flow, and some of it is really rich in coccolith-type carbonates which are very soft and will close around the sand injected to 'prop' open the fracs too quickly, rendering the frac job useless. It works in some places, it doesn't in others, but if large-scale development were to occur, the water issue would be the paramount blockade to economic success.
-They have tried
acid fracs where they try to dissolve the carbonate components with hydrochloric acid and the silica components with hydrofluoric acid, but the varying compositional makeup of the formation makes choosing your acid type ratios difficult.
-They have tried
flushing in condensates (light hydrocarbons, similar to gasoline) down the wellbore to incorporate them with the in-situ heavy oil to make it less viscous and easier to flow. Most Monterey oil has an API Gravity (sort of an industry proxy for density) of maybe 15 (API gravity of Canadian Oil Sands Bitumen is like 8, water is 10, motor oil is around 30, West Texas Intermediate is 40, gasoline is maybe 50, for reference) so it is quite heavy and viscous. It won't flow easily, especially when it despressurizes as it flows up the wellbore and exsolves natural gas (methane, ethane and propane gases are always dissolved in oil at reservoir conditions which makes the liquid less viscous, but escapes during depressurization as it is produced) present in oil when it is deep in the reservoir, so the theory is if you pump in a lighter hydrocarbon, it will incorporate and reduce the heavy oil viscosity of the oil in the Monterey. Some of the oil has API Gravities of 35 though, it just depends on what type of organism died in that area, as all organisms will develop into different oil gravities during diagenetic processes.
-They have tried
Steam Injection which works well in Kern County shallower heavy oil pools. The theory of steam injection (technically it is called CSS or Cyclic Steam Stimulation) is as follows: pump in a bunch of steam into a heavy oil reservoir, shut in your injection well for a month or so and let that steam soak into the formation and reduce oil viscosity, then fire up your production wells and make it rain. The big risk of CSS is that if you do not have a good 'cap rock' (impermeable shale sitting on top of the permeable reservoir), the pressure of the steam flood will fuck up the integrity of the cap rock and steam will escape upwards, leaving your heavy oil high and dry. You need a good, thick consistent permeable reservoir, but those are hard to find in the Monterey.
If any of you have been to like Ojai, you will have seen some production going on around there, the Ventura County play. That thing is fucking incredible - ONE BILLION barrels have been produced from an area that is like 2-3 square miles! And that is probably only a 10% recovery factor of the original oil in place because it's not like the guys who were pumping that oil in the 1950s were using elaborate steam injection methods to lower that viscosity. I bet if you could get in a Canadian group with steam injection experience from the Oil Sands you would recover up to 50% of original oil in place, but how would the California government allow steam injection now with water shortages and the threat of earthquakes?
I therefore don't think there will ever be a singular 'boom' in the Monterey. Instead, we will see small successes as companies slowly implement new completion strategies to the various components of the heterogeneous Monterey over time. To me, a boom is defined as a massive discovery in a homogenous geologic setting where a new technology unlocks a massive petroleum deposit that has been idly sitting there, patiently waiting for the right completion strategy to exploit it. Maybe something like
The Green River Formation in Wyoming...
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