05 August 2010

Ancient Geologic Upheaval Still Hides Most of Earth's Oil

NYT
Scientists have known for quite a while that most of Earth's oil came from vast numbers of oceanic microscopic organisms -- rather than from dead dinosaurs. From diatoms to micro-algae to cyanobacteria and more, these microscopic life forms thrived on warmer seas and higher levels of atmospheric CO2 than are presently available to sea life. Many of these sea creatures are capable of converting gaseous or dissolved CO2 directly into oils and hydrocarbons of various types, and would cheerfully welcome much higher levels of CO2 in the atmosphere and in the oceans, if only they could get it.
Geologists scour the planet for the sedimentary basins of ancient seas, in order to find the vast deposits of oil, gas, and other hydrocarbons still waiting to be discovered. Humans may have used perhaps one tenth of exploitable oil deposits, but Al Fin engineers reckon we have used only about one one hundredth. Not that oil is an ideal energy source. Far from it. But we should know that we are quite far from running out -- even while we are discovering how to grow these tiny organisms for ourselves, to produce a wide range of materials, feeds, and fuels at the time and place of our own choosing.
Some of the ancestral waters that made the planet’s oil still exist, like the Gulf of Mexico, while others have long vanished, like the ocean that produced the massive oil fields of the Middle East. The bodies come and go because the earth’s crust, through seemingly rigid, actually moves a great deal over geologic time, tearing apart continents and ocean basins and rearranging them like pieces of a giant jigsaw puzzle.

The secret of the oil story turned out to be understanding how the bygone oceans, ancient seas and smaller bodies of water produced complex environmental conditions that raised the prevalence of microscopic life and ensured its deep burial, producing what eventually became the earth’s main oil reservoirs.

The clues accumulated over more than a century and included discoveries from geology, chemistry and paleontology. An early indication was that petroleum discoveries were always associated with ancient beds of sedimentary rock — the kind that forms when debris rains down through water for ages and slowly grows into thick seabed layers.

...The process typically starts in warm seas ideal for the incubation of microscopic life. The sheer mass is hard to imagine. But scientists note that every drop of seawater contains more than a million tiny organisms.

Oil production begins when surface waters become so rich in microscopic life that the rain of debris outpaces decay on the seabed. The result is thickening accumulations of biologic sludge.

...“The organics got buried quickly because of the heavy sediment flow,” Dr. Tinker said. “So they didn’t get biodegraded as quickly. You preserved the organic richness.”

He said the flow was so heavy that the growing accumulations keep pressing the lower sediment layers deeper into the earth, forcing them into hot zones where the organic material got transformed into oil. The process involves a long series of chemical reactions that slowly turn life molecules into inanimate crude.

“The gulf has miles and miles of sediments,” he said. “So that gets the source rocks down into the kitchen where they cook.”

The standard temperature for oil formation is between 120 and 210 degrees Fahrenheit.

...Many countries and oil companies are now racing to exploit the geological happenstance of deep coastal waters. Hot spots include offshore areas of Angola, Azerbaijan, Congo, Cuba, Egypt, Libya and Tanzania, while countries like Canada and Norway, which have long pursued offshore drilling, are pushing ahead with new plans. Cambridge Energy Research Associates, a consulting firm, estimates that global deepwater extraction could roughly double by 2015, the output rivaling what Saudi Arabia produces on land. _NYT
The new offshore oil fields coming on line will rival Saudi Arabian production -- even if the Saudis decide to ramp up their production even higher than at present.

But many more giant fields await discovery until geologists develop better tools to find ancient ocean basins lying beneath subsequent overlaying deposits of seismic and volcanic upheaval. Earth's warm water sea floors have been turned around a great deal over the past billions of years. It is likely that we have not yet found the richest fossil fuel fields.

For most of the planet, geologists simply do not have a clue what lies beneath. They will need far better tools than the primitive seismic, electromagnetic, and other tools which currently limit their vision. But those tools are coming. And those vast unknown deposits will be found, if they are ever needed.

Previously published at Al Fin Energy

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