Guest Seinfeld routine by David Middleton
In part one of this series, we looked at Peak Oil and its irrelevance to energy production. In Part Deux, we will look at “abiotic oil,” a real(ish) thing that really doesn’t matter outside of academic discussions and SyFy blogs.
A note on terminology
Some refer to this as “abiogenic oil.” This is not a useful term because all oil is abiogenic. The generally accepted theory of petroleum formation doesn’t state that it is a biogenic process. I discussed this in detail in a 2017 post. I don’t intend to restate it here.
In this post, “abiotic oil” refers to petroleum formed by processes that do not rely on biological source material. The carbon in “abiotic oil” must be inorganic.
A real example of abiotic “oil”
The Lost City Hydrothermal Field is located on the Mid-Atlantic Ridge, about 15 km (~9 mi) west of the spreading center, in water depths ranging from 750-900 m (~2,500-3,000′) (Kelley et al., 2005).
The Lost City Hydrothermal Field appears to be a genuine example of abiotic oil, or at least abiotic oil-like material formed by the Fischer-Tropsch process.
Deep-ocean vents are a source of oil and gas
Hydrocarbons bubble up from the mid-Atlantic’s Lost City.
Undersea thermal vents can yield unexpected bounty: natural gas and the building blocks of oil products. In a new analysis of Lost City, a hydrothermal field in the mid-Atlantic, researchers have found that these organic molecules are being created through inorganic processes, rather than the more typical decomposition of once-living material.
Most of the planet’s oil and natural gas deposits were created when decomposing biological matter is ‘cooked’ in high temperatures underground. But non-biological hydrocarbons have also been found deep inside the Earth, where chemical processes create the molecules from inorganic sources such as rock.
Among other measurements, the team analysed the amount of carbon-13 in methane, which contains one carbon atom, and in hydrocarbons containing two, three, and four carbon atoms. As the number of carbon atoms rose, the concentration of carbon-13 fell — the opposite trend to that seen in biologically derived hydrocarbons.
Instead, the pattern of isotopes suggest that a chemical process called the Fischer-Tropsch process is at work in Lost City, creating bigger and bigger hydrocarbons in the hydrogen-rich environment. Although the concentrations were too low to detect without a filter, small amounts of larger hydrocarbons such as kerosene and octane may also be produced.
The team also found that the methane in Lost City contained no carbon-14, suggesting the carbon source for the hydrocarbons comes from within the mantle, far away from organisms that might have had contact with the global carbon cycle at the surface.
Traces of kerosene and octane demonstrate that at least some of the components of crude oil can be formed naturally by the Fischer-Tropsch process.
A close, but no cigar, example of abiotic oil
The Pescadero and Guyamas Basins are sediment-filled depressions respectively at the southern end and in central portion of the Gulf of California (AKA Vermilion Sea, Sea of Cortez). Oil-like material has been associated with hydrothermal vents in both of these basins.
The Guaymas and Pescadero Basins are more consistent with the conventional theory of petroleum formation than the abiotic oil hypothesis.
June 2, 2015
MBARI researchers discover deepest known high-temperature hydrothermal vents in Pacific Ocean
In spring 2015, MBARI researchers discovered a large, previously unknown field of hydrothermal vents in the Gulf of California, about 150 kilometers (100 miles) east of La Paz, Mexico. Lying more than 3,800 meters (12,500 feet) below the surface, the Pescadero Basin vents are the deepest high-temperature hydrothermal vents ever observed in or around the Pacific Ocean. They are also the only vents in the Pacific known to emit superheated fluids rich in both carbonate minerals and hydrocarbons. The vents have been colonized by dense communities of tubeworms and other animals unlike any other known vent communities in the in the eastern Pacific.
Reflecting on the discovery, Clague commented, “Before the AUV survey of Pescadero Basin, all we knew was that this area was really deep and filled with sediment. I was hoping to find a few outcrops of lava on the seafloor. But we got lucky. The vent field was right on the edge of our survey area, along a fault at the western edge of the basin.”
The AUV and ROV dives showed that the new field extends for at least 400 meters (one quarter mile) along this fault. Within this area the researchers found at least three active hydrothermal chimneys up to 12 meters (40 feet) tall, as well as dozens of low mounds that are most likely collapsed chimneys.
After his ROV dive, Clague noted, “This site was not at all what I was expecting.” For one thing, the fragments of chimneys that the ROV brought back to the surface were quite different from those collected at other vents in the area. The Pescadero chimneys consisted entirely of light-colored carbonate minerals instead of the dark sulfide minerals that are abundant in hydrothermal chimneys elsewhere in the Gulf.
The Pescadero Basin is only the second place in the world where carbonate chimneys (instead of ones made primarily of sulfides) have been found in the deep sea. The other known location is the “Lost City” vent field in the middle of the Atlantic Ocean, at a spot on the Mid-Atlantic Ridge.
The geologists also noticed that their rock samples smelled like diesel. They hypothesize that hot hydrothermal fluids migrating upward through the thick sediments of the Pescadero Basin “cook” organic matter in the sediment, converting it into petroleum-like hydrocarbons—a process that has been observed at several other vents in the Pacific. Hydrocarbons may provide nutrition for the unusual microbes that thrive at these vents.
The “oil” of the Guayamas Basin is very young and formed very quickly…
Hydrothermal oil of Guaymas Basin and implications for petroleum formation mechanisms
BORYS M. DIDYK* & BERND R. T. SIMONEIT†
*Refineria de Petroleo Concon, Casilla 242, Concon, Chile
†Petroleum Research Group, College of Oceanography, Oregon State University, Corvallis, Oregon 97331, USA
PETROLEUM-LIKE hydrocarbons have been detected in thermally altered Recent sediments of Guaymas Basin and petroleum-like hydrocarbon impregnations were found in hydrothermal mounds on the sea floor and associated with hydrothermal vent emissions. Here we report the evaluation of such a hydrothermal oil, which we find to be similar to conventionally exploited crude oils. Its young geological age (< 5,000 yr, 14C) indicates that a significant fraction of the organic carbon in the oil has completed the transformation from biomass to migrating oil in less than 5,000 years, thus limiting the oil generation, explusion and migration processes to a geologically short timescale. We estimate the generation potential of such hydrothermal oil and discuss its implications to our understanding of the petroleum generation, expulsion and migration mechanisms.
The Guaymas and Pescadero Basins are “fast” hydrocarbon kitchens and a pretty decent window into how oil petroleum may actually form.
How do we know that Abiotic Oil doesn’t matter?
We’ll revisit the Eugene Island 330 (EI 330) oilfield to explain why Abiotic Oil doesn’t matter. The reservoir “rocks” in the EI 330 field during the Calabrian Stage of the Pleistocene Epoch (~0.75 to 1.5 Ma), they are very “young.”
The oil in EI 330’s Pleistocene reservoirs was not sourced from the Pleistocene shale in the field. It is organic-poor, highly oxidized and contains “predominantly terrestrial kerogen” (Holland et. al., 1999). The oil exhibits clear indications of long vertical migration (Holland et. al., 1999) The most likely source rock is the Jurassic Smackover carbonate (Losh et al., 2002). There are no wells anywhere near EI 330 that have drilled deep enough to test the Smackover. The deepest well in the field didn’t even reach the Pliocene. It encountered hard pressure in the Lower Pleistocene at depth of about 13,500′. The Smackover formation was probably at a depth of about 16,000′ when the oil was formed and expelled (Holland et al., 1999); however rapid sedimentation and subsidence of the basin during the Pleistocene currently puts the Smackover at a depth of nearly 50,000′ (Losh et al., 2002).
Unlike the Williston Basin or even East Texas Salt Basin, where source rocks can be directly tied to oil in reservoir rocks. The presumed source rocks in most of the Gulf of Mexico are too deep to drill.
This is where the story gets “interesting.”
COULD it be that many of the world’s oil fields are refilling themselves at nearly the same rate they are being drained by an energy-hungry world?
A geochemist at the Woods Hole Oceanographic Institution in Massachusetts says she believes that hitherto undetected gas and oil reservoirs lying at very great depths within the earth’s crust could stave off the inevitable oil depletion much longer than many experts have estimated.
The scientist, Dr. Jean K. Whelan, whose research is part of a $2 million Department of Energy exploration program in the Gulf of Mexico south of New Orleans, has found evidence of differences in the composition of oil over periods of time as it flows from greater to shallower depths. By gauging degradative chemical changes in the oil resulting from action by oil-eating bacteria, she infers that oil is moving in quite rapid spurts from great depths to reservoirs closer to the surface.
Skeptics of Dr. Whelan’s hypothesis acknowledge that oil is almost certainly flowing into certain reservoirs from somewhere, but say her explanation remains to be proved, as does the exact extent of the phenomenon.
A site in the gulf of particular interest to the Pennzoil Exploration and Production Company and several independent scientific teams, including Dr. Whelan’s group, is Eugene Island Block 330, which is not an island but a patch of sea floor 700 feet beneath the water’s surface. Discovered in 1972, an oil reservoir some 6,000 feet beneath Eugene Island 330 is one of the world’s most productive oil sources; it has yielded more than one billion barrels, or 42 billion gallons, and is still going strong.
The New York Times article got at least one thing very wrong. The cumulative oil production at the end of 1995 was only a bit over 340 million bbl. Even if you count the gas, it was only 608 million BOE (barrels oil equivalent). And, despite evidence that oil was still migrating into the EI 330 reservoirs (Nunn et al., 1996) there was no evidence that the field was “refilling [itself] at nearly the same rate [it was] being drained.”
Eugene Island 330 was clearly not “refilling [itself] at nearly the same rate [it was] being drained.”
Dr. Whelan was referring to oil migrating from deep organic-rich Jurassic source rocks… However, “The mystery of Eugene Island 330” quickly became evidence for Thomas Gold’s unfounded and generally falsified hypothesis…
The deep-seated oil source at Eugene Island strongly supports T. Gold’s theory about The Deep Hot Biosphere. Gold holds:
“that oil is actually a renewable, primordial syrup continually manufactured by the earth under ultrahot conditions and tremendous pressures. As this substance migrates toward the surface, it is attacked by bacteria, making it appear to have an organic origin dating back to the dinosaurs.”
Art Bell’s Coast to CoastScience Frontiers Online, Jul-Aug 1999
Setting aside the extensive evidence correlating Pleistocene, Pliocene and Miocene reservoir “rocks” in the Gulf of Mexico to deeper Lower Tertiary, Cretaceous and Jurassic source rocks in and around the Gulf (Hood et al., 2002), what if those weren’t the source rocks? What if the oil was actually migrating up from the lower crust or mantle?
The results are the same.
It doesn’t really matter where the oil came from. It has to be produced from economically viable accumulations. The accumulations have to have a sufficient volume to justify the costs of drilling the wells, installing the platform, pipelines and all of the other necessary infrastructure. The accumulation also has to produce at a sufficient rate to cover the costs of operating the wells, platforms, pipelines, etc.
However, the volume of oil and the production rate do not have to cover the “energy invested” in everything from drilling the wells, to installing the platform, building the drilling rigs, workboats or growing the food to feed the people working on the drilling rigs and production platforms.
To be continued
Part Trois will address the real(ish) nature of Energy Returned On Energy Invested (EROEI) and its Seinfeldian position among irrelevant things.
Browne, Malcolm W. “Geochemist Says Oil FieldsMay Be Refilled Naturally.” The New York Times, The New York Times, 26 Sept. 1995, https://nyti.ms/2Xyh428.
Corliss, William R. “The Mystery of Eugene Island 330.” Science Frontiers Online. No. 124: Jul-Aug 1999. http://bit.ly/2ICmEx8.
Courtland, Rachel. “Deep-Ocean Vents Are a Source of Oil and Gas.” Nature News, Nature Publishing Group, 31 Jan. 2008, https://go.nature.com/2XHXYHd.
Didyk, Borys M., and Bernd R. T. Simoneit. “Hydrothermal Oil of Guaymas Basin and Implications for Petroleum Formation Mechanisms.” Nature, vol. 342, no. 6245, 1989, pp. 65–69., doi:10.1038/342065a0.
Fulton-Bennett, Kim, and Meilina Dalit. “New Study Challenges Prevailing Theory about How Deep-Sea Vents Are Colonized.” MBARI, 5 Sept. 2017, http://bit.ly/2tF7GiK.
Fulton-Bennett, Kim, and Jenny Paduan. “MBARI Researchers Discover Deepest Known High-Temperature Hydrothermal Vents in Pacific Ocean.” MBARI, 10 Sept. 2018, http://bit.ly/2XDaw2q.
Galloway, William E., et al. “Gulf of Mexico.” GEO ExPro, 21 Jan. 2014, http://bit.ly/2rAPC8i.
Hines, Sandra. “Lost City Pumps Life-Essential Chemicals at Rates Unseen at Typical Black Smokers.” UW News, University of Washington, 31 Jan. 2008, http://bit.ly/2XHY0Pl.
Hood, K. C., L. M. Wenger, O. P. Gross, and S. C. Harrison, 2002, “Hydrocarbon systems analysis of the northern Gulf of Mexico: Delineation of hydrocarbon migration pathways using seeps and seismic imaging, in Surface exploration case histories: Applications of geochemistry, magnetics, and remote sensing,” D. Schumacher and L. A. LeSchack, eds., AAPG Studies in Geology No. 48 and SEG Geophysical References Series No. 11, p. 25–40.
Holland, David S, et al. “Eugene Island Block 330 Field–U.S.A. Offshore Louisiana.” Search and Discovery Article #20003, AAPG, 1999, http://bit.ly/2IzQUcd. Published in AAPG Treatise of Petroleum Geology, Atlas of Oil and Gas Feilds, Structural Traps III, p. 103-143; adapted for online presentation
Kelley, D. S. “A Serpentinite-Hosted Ecosystem: The Lost City Hydrothermal Field.” Science, vol. 307, no. 5714, 2005, pp. 1428–1434., doi:10.1126/science.1102556.
Losh, Steven, et al. “Reservoir Fluids and Their Migration into the South Eugene Island Block 330 Reservoirs, Offshore Louisiana.” AAPG Bulletin, vol. 86, 2002, pp. 1463–1488., doi:10.1306/61eedcce-173e-11d7-8645000102c1865d.
Middleton, David. “Oil – Where Did It Come from?” Watts Up With That?, 18 Feb. 2017, wattsupwiththat.com/2017/02/18/oil-where-did-it-come-from/.
Nunn, J.A. & Roberts, S.J. & Cathles, Lawrence & Anderson, Roger. (1996). “Fluid migration in the Eugene Island block 330 area, offshore Louisiana”. AAPG Bulletin – AAPG BULL. 5.
St. C. Kendall, Christopher G, et al. “World Source Rock Potential through Geological Time: A Function of Basin Restriction, Nutrient Level, Sedimentation Rate, and Sea-Level Rise.” Search and Discovery Article #40472, AAPG, 30 Nov. 2009, http://bit.ly/2XHY1CT. Adapted from oral presentation at AAPG Annual Convention, Denver, Colorado, June 7-10, 2009 Please refer to companion article, “The Giant Oil Field Evaporite Association: A Function of the Wilson Cycle, Climate, Basin Position and Sea Level,”
Whittaker, Joanne M., et al. “Global Sediment Thickness Data Set Updated for the Australian-Antarctic Southern Ocean.” Geochemistry, Geophysics, Geosystems, vol. 14, no. 8, 2013, pp. 3297–3305., doi:10.1002/ggge.20181.
via Watts Up With That?
April 23, 2019 at 04:35PM