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(petroleum-based fuels), including gasoline, diesel, jet, heating, and other
fuel oils, and liquefied petroleum gas.
Due to its high energy density, easy transportability and relative
abundance, it has become the world's most important source of energy
since the mid-1950s. Petroleum is also the raw material for many
chemical products, including solvents, fertilizers, pesticides, and plastics;
the 16 % not used for energy production is converted into these other
materials.
Petroleum is found in porous rock formations in the upper strata of some
areas of the Earth's crust. There is also petroleum in oil sands. Known
reserves of petroleum are typically estimated at around 1.2 trillion barrels
without oil sands, or 3.74 trillion barrels with oil sands. However, oil
production from oil sands is currently severely limited. Consumption is
currently around 84 million barrels per day, or 4.9 trillion liters per year.
Because of reservoir engineering difficulties, recoverable oil reserves are
significantly less than total oil-in-place. At current consumption levels,
and assuming that oil will be consumed only from reservoirs, known
reserves would be gone in about 32 years, around 2039, potentially
leading to a global energy crisis. However, this ignores any new
discoveries, changes in consumption, using oil sands, using synthetic
petroleum, and other factors.
Exercise 15. Discuss the following questions.
1. What product do we get out of the ground? – Oil and gas are the
products that we get out of the ground.
2. What collects on the ocean bottoms all over the world? – These
organisms live all over the oceans and their bodies fall and collect on
the ocean bottom all over the world.
3. Is there abundance of dead organisms? – Yes, there are.
4. What is needed for these organisms to be transformed into petroleum?
– Some special conditions are needed to be met.
5. Are there any conditions for the oil to be made? – First, the area that
the kerogen collects must be a restricted basin, a depression where
sediment can accumulate and where there is poor water circulation.
There needs to be a trap, something that is non-porous and non-
permeable that will hold the petroleum in the reservoir and prevent it
from migrating further. Finally, there needs to be enough heat and
pressure to sufficiently cook the oil and gas out of the kerogen.