The Making of Oil
Birth of a Reservoir


"Something in the order of 500 million years ago there was only simple life in the seas, and these shallow seas would be rich with organic, living organisms.

Roy Nurmi

Plankton and algae, proteins and the life that's floating in the sea, as it dies, falls to the bottom, and these organisms are going to be the source of our oil and gas.

When they're buried with the accumulating sediment and reach an adequate temperature, something above 50-70° Centigrade they start to cook. This transformation, this change, changes them into the liquid hydrocarbons that move and migrate, will become our oil and gas reservoir."

Roy Nurmi
Schlumberger Interpretation Advisor - Geology


Movement of the Continents: Plate tectonics, driven by the earth's internal heat, is the engine that moves the continents. This movement forms valleys where sediments and decaying organic matter can collect, ultimately becoming oil reservoirs.

North Sea

Rise and Fall of the North Sea: During the millions of years that moving continents build mountains and valleys, sea level rises and falls thousands of times, producing radical changes in coastlines. What is now deep water was once a shallow sea, where the organic ingredients to form oil were deposited.

Reservoir cross section

Evolution of the Reservoir: Most oil reservoirs are created when a valley sinks and is flooded by the sea. As the seafloor plunges, it accumulates three key ingredients: a source for oil -- organic matter -- sediments that form a reservoir to hold oil, and denser sediments that trap oil in the reservoir.

more info

Summary of Birth of a Reservoir.
What is a Reservoir?


Movement of the Continents Rise and Fall of the North Sea
Evolution of the Reservoir

The Making of Oil 
Birth of a Reservoir
Tapping the Reservoir
Related Links
Digging Deeper

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