Naturally - Sometimes Rapidly. There Are More Oil Seeps Than All The Tankers On Earth
Deep underwater, and deeper underground, scientists see surprising hints that gas and oil deposits can be replenished, filling up again, sometimes rapidly.Although it sounds too good to be true, increasing evidence from the Gulf of Mexico suggests that some old oil fields are being refilled by petroleum surging up from deep below, scientists report. That may mean that current estimates of oil and gas abundance are far too low.
Recent measurements in a major oil field show "that the fluids were changing over time; that very light oil and gas were being injected from below, even as the producing [oil pumping] was going on," said chemical oceanographer Mahlon "Chuck" Kennicutt. "They are refilling as we speak. But whether this is a worldwide phenomenon, we don't know."
Also not known, Kennicutt said, is whether the injection of new oil from deeper strata is of any economic significance, whether there will be enough to be exploitable. The discovery was unexpected, and it is still "somewhat controversial" within the oil industry.
Kennicutt, a faculty member at Texas A&M University, said it is now clear that gas and oil are coming into the known reservoirs very rapidly in terms of geologic time. The inflow of new gas, and some oil, has been detectable in as little as three to 10 years. In the past, it was not suspected that oil fields can refill because it was assumed the oil formed in place, or nearby, rather than far below.
According to marine geologist Harry Roberts, at Louisiana State University, "petroleum geologists don't accept it as a general phenomenon because it doesn't happen in most reservoirs. But in this case, it does seem to be happening. You have a very leaky fault system that does allow it to migrate in. It's directly connected to an oil and gas generating system at great depth."
What the scientists suspect is that very old petroleum -- formed tens of millions of years ago -- has continued migrating up into reservoirs that oil companies have been exploiting for years. But no one had expected that depleted oil fields might refill themselves.
Now, if it is found that gas and oil are coming up in significant amounts, and if the same is occurring in oil fields around the globe, then a lot more fuel than anyone expected could become available eventually. It hints that the world may not, in fact, be running out of petroleum.
"No one has been more astonished by the potential implications of our work than myself," said analytic chemist Jean Whelan, at the Woods Hole Oceanographic Institution, in Massachusetts. "There already appears to be a large body of evidence consistent with ... oil and gas generation and migration on very short time scales in many areas globally," she wrote in the journal Sea Technology.
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