
25 
(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.