Black gold

An estimated 513 billion barrels of “technically recoverable” heavy oil lie in Venezuela’s Orinoco Oil Belt, a 50,000 square kilometre region in the East Venezuela Basin Province.

Worldwide consumption of petroleum was 85.4 million barrels per day in 2008. The three largest consuming countries were United States with 19.5 million barrels per day, China with 7.9 million barrels per day, and Japan with 4.8 million barrels per day. So the Venezuelan heavy oil represents a potential supply that could last a decade at the current rate of consumption.

The United States Geological Survey (USGS) has carried out the first assessment that identifies how much oil might be technically recoverable using currently technology and standard industry practices. According to USGS Energy Resources Program Coordinator Brenda Pierce, this part of the world has one of the world’s largest recoverable oil accumulations. The USGS’s report is part of its program directed at estimating the technically recoverable oil and gas resources of priority petroleum basins worldwide. This is the largest accumulation ever assessed by the USGS.

“Knowing the potential for extractable resources from this tremendous oil accumulation, and others like it, is critical to our understanding of the global petroleum potential and informing policy and decision makers,” explains Pierce. “Accumulations like this one were previously very difficult to produce, but advances in technology and new understandings in geology allow us to assess how much is now technically recoverable.”

USGS team member and a co-author of the report, Christopher Schenk explains further: “Heavy oil is a type of oil that is very thick and therefore does not flow very easily. As a result, specialized production and refining processes are needed to generate petroleum products, but it is still oil and can generate many of the same products as other types of oil.”

The estimated petroleum resources in the Orinoco Oil Belt, range from 380 to 652 billion barrels of oil (at a 95 and 5 percent chance of occurrence, respectively). Schenk says that the estimates are based on a rate of oil recovery of between 40 and 45 percent.

Orinoco (Credit: USGS)
Credit: USGS


However, others are sceptical that these oil reserves are economically or environmentally viable. Venezuelan oil geologist Gustavo Coronel told the Associated Press that he doubted the recovery rate could be much higher than 25 percent given the nature of the crude oil. More intriguing is that the USGS announcement seems to have been timed to coincide with an international auction for drilling rights in the Orinoco Belt which took place on 28th January, with results to be announced on 10th February.

Moreover, there are no little energy and environmental costs to be considered in recovering heavy crude oil as it is not necessarily as easy to extract as conventional crude oil. Moreover, the existence of such reserves while perhaps saving us from short-term oil shortages does not address the issues of carbon emissions and potential climate change.


USGS Assessment

Energy Resources Program

Auction news

Crude claims

AP report

Mercury mystery unearthed

A recent study shows just how long mercury pollutants can persist in the environment and continue to cause problems. The study demonstrates that riverbank and floodplain soils contaminated by a textile manufacturing plant in Waynesboro, Virginia more than half a century ago are the major source of mercury in fish from several Shenandoah Valley rivers.

According to US Geological Survey scientist Jack Eggleston approximately 200 kg of mercury enters the South River every year. However, in order to meet safety standards in fish for human consumption, mercury loads should not exceed about 2 kg pounds per year. Such a tolerance level would require a 99% reduction in contamination asserts hydrologist Eggleston who has authored a report highlighting this serious environmental problem.

Mercury from the textile plant washed into the South River and subsequently contaminated the South Fork Shenandoah River, the Shenandoah River, and the floodplains along the three rivers. The textile plant, operated by DuPont, discharged mercury waste into the river during the period 1929 to 1950. It is difficult to know in retrospect whether those responsible for this action gave any consideration to the long-term environmental impact.

Since 1977, the Commonwealth of Virginia has enforced a fish consumption health advisory on 200 km of river downstream of the textile plant. Safety standards set by the US Environmental Protection Agency state that 0.3 parts per million of mercury in fish are allowable. High concentrations of mercury occur in fish because mercury accumulates throughout the lifetime of an organism. Smaller fish eaten by bigger, predatory fish and so on leads to even greater accumulation up to the point at which people are eating the fish.

During the study, USGS scientists and partners from the Virginia Department of Environmental Quality (VDEQ), and the EPA collected and analysed hundreds of water and sediment samples. They then used computer models to simulate water, sediment and mercury movement in the South River watershed, which revealed how the mercury can still be entering the water 50 years after the plant stopped discharging.

“Now we know why fish continue to have elevated mercury,” says Eggleston. Knowing that contaminated soil is the issue could allow a remediation program to be instigated to extract the toxic metal from the soil.

The South River Science Team working on the project also comprised scientists from government agencies, universities, DuPont itself, and environmental groups who have met regularly over the past decade. DuPont provides financial support for the work.

South Fork Shenandoah River (Credit:
South Fork Shenandoah River (Credit:


USGS mercury report

Ocean-going stalks fight global warming

Burying crop residues at sea may help reduce global warming, according to researchers in the USA. They suggest that transporting millions of tonnes of bailed up cornstalks, wheat straw, and other crop residues from farms, and burying it in the deep ocean will lock up huge amounts of carbon. The carbon would otherwise be released into the atmosphere as the crops rot. Of course, such a macroengineering project would require energy for harvesting of the residues, bailing, transportation, and associated effort.

Writing in the journal Environmental Science and Technology, Stuart Strand of the College of Forest Resources, at the University of Washington, in Seattle, Washington, together with Gregory Benford of the Department of Physics and Astronomy, at the University of California, in Irvine, suggest extensive research be carried out into this approach to so-called carbon sequestration.

Professor Stuart E. Strand

Professor Stuart E. Strand

Atmospheric carbon dioxide levels are rising because of the increasing amounts of the gas released by human activities involving the burning of fossils fuels. Simulations suggest that the associated rise in global average temperatures associated with the greenhouse effect of this gas will have catastrophic consequences for people and life on earth.

As such, any large-scale, or macro, engineering project aimed at ameliorating the effects of rising carbon dioxide levels will have to process large amounts of carbon efficiently with little energy use. It will also have to be a repeatable process that can be done again and again to counter the effects of decades of environmental neglect. Moreover, the carbon must remain sequestered and so unable to re-enter the atmosphere for thousands of years. If it is not it will simply be deferring the problem for future generations. Any such solution must be implemented soon, the team suggests.

Gregory Benford

Gregory Benford

According to Strand and Benford, the only approach that meets all these criteria is the removal of crop residues and their burial in the deep ocean. In their research paper, they show that this method to be 92% efficient in sequestration of crop residue carbon. This, they say, far outweighs any benefits from converting those waste materials into biofuels (just 32% efficiency) or carbon sequestration in soil (a mere 14% efficient).

Wasted hay bails could reverse global warming (Photo by David Bradley)

Wasted hay bails could reverse global warming (Photo by David Bradley)

Deep ocean sequestration can potentially capture 15% of the current global carbon dioxide annual increase, the researchers calculate, returning that carbon back to deep sediments, confining the carbon for millennia, while using existing capital infrastructure and technology.

Further reading

Env. Sci. Technol., 2009, in press

Professor Stuart E. Strand homepage

Gregory Benford homepage

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carbon sequestration
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