A grain of sand. Not very significant, you say?
Well, put it inside downhole pumping equipment or any other precision instrument-or in your eye-and its importance increases dramatically. As Einstein said, "Everything is relative."
Some of the most diminutive elements on the planet, in fact, actually are among the most sizeable because of the relativity factor.
And the quantity factor.
Multiply the tiniest of microorganisms a quadrillion-fold and you have a powerful force. Ask any doctor. Or biochemist. Or oilman.
Oilman?
Geological theory
The organic theory of petroleum formation holds that oil and gas are formed from the breakdown of microscopic organic matter-algae-like plants, animals, or both-that lived in ancient rivers and seas. As these organisms died, they fell slowly to the seabed, along with a great deal of silt and mud, and were eventually covered over by sediment that cut them off from oxygen in the water.
The more the sediment built up, the deeper the organisms (and sediment) became. And the deeper they became, the more the forces of heat and pressure began to affect them.
According to the theory, over eons of time, high pressure, heat, bacteria, chemical reactions, and other forces combined to transform the sediment into sedimentary rock (sponge-like on a microscopic level). At the same time, temperatures of 66-177° C. (150-350° F.) separated hydrogen and carbon molecules from the organisms into hundreds of kinds of hydrocarbon molecules. Then, at up to 260° C. (500° F.), a chemical process took place to break trapped hydrocarbon molecules into methane gas.
Note that large animals, such as dinosaurs, had nothing to do with it.
Ekofisk chalk
One of the many pieces of literature that inundate editors' desks daily at OGJ is an interesting little quarterly called the Norwegian Petroleum Diary, published by the Norwegian Petroleum Directorate (NPD). A recent edition had some data on microorganisms that is worthy of note.
Scientists from NPD-geologist Christian Magnus and paleontologist Robert W. Williams-provided the Diary editor with information about the Ekofisk field and the particular microorganisms that formed the chalk within which the field's hydrocarbons rest.
Ekofisk, one of Norway's first producing fields, ranks as one of the world's largest. John Mihm, research head of Phillips Petroleum Co., the field's operator, said he now expects the field to produce for 100 years, the Diary said.
That's a lot of microorganisms.
Ekofisk chalk reservoirs were created during the Cretaceous period, along with some of the other largest oil reservoirs such as those in Saudi Arabia and South America.
During this period 142-65 million years ago, the climate was warm, much of the Earth was covered with water, and the water was full of single-celled algae called coccolithophorids that actually created the huge chalk deposits.
Several times a year a vast number of these organisms bloomed and died, then floated to the bottom, creating the snowy chalk sediment that trapped what would later become enormous reserves of hydrocarbons.
Dinoflagellate cysts
The chalk holding Ekofisk oil and gas was created from these strong but infinitesimal coccolith flakes. And the empty casings or shells of microscopic dinoflagellate cysts formed a principal constituent of kerogen, the organic compound that eventually became the field's petroleum.
Kerogen, which contains "enormous numbers of empty dinoflagellate cysts," is the residue left when some species of the algae entered a dormant stage during reproduction.
"They encapsulate themselves in a flexible, plastic-like shell, discard their cellulose armour, and drift to the seabed," the Diary reported. "A hatch opens after a while and the emerging cell immediately divides into two. The residual cyst always has a small opening in one side, but it stores an incredible amount of energy in the material from which it is made."
The many varieties of dinoflagellate cysts differ from each other in shape, yet each has one common characteristic, two or more (usually many) whip-like appendages that enable them to move about in water. They are strong but exquisitely fragile looking.
They're alive
NPD has archived about 1,500 species of the organisms, which Williams described as "among the most important microfossils from the Jurassic, Cretaceous, and Tertiary periods." There are about 3,600 known species described worldwide. Perhaps the most interesting thing about all this is that many species of these hardy microorganisms have survived to the present day. They reside "in virtually all aquatic environments, coping with the most extreme conditions," Williams said in the Diary report. Conditions can range from snowy mountaintop waters to hot, saline desert pools. "The cysts can survive hydrochloric acid or hydrogen fluoride, making it easy to filter them out of sediment samples," he said.
He also indicated that dinotoxins from some species of dinoflagellates are lethal, among the most deadly natural substances, making mussels toxic and once used by American Indians to kill European intruders. The microorganisms are only thousandths of a millimeter across.
Makes our little grain of sand now seem rather enormous, doesn't it?
Relatively speaking, of course.
