NON-CONVENTIONAL ENERGY RESOURCES AND UTILISATION 41
In 1973 the world oil outlook changed dramatically, following an embargo imposed by the Arab
members of OPEC on countries that they believed were providing assistance to Israel at the time of the
1973 October war between Israel and her neighbors. By coincidence, at the same time OPEC ministers
decided to raise the oil price from $3 to $5.12. The day following this announcement in Oct. 73, the
Arab members (OAPEC) agreed an immediate 5% reduction in oil production. Subsequently, the inter-
national oil price rose to $20 a barrel by Dec. 73. Shortly after this OPEC increased the oil price to
$11.65 per barrel, giving a five-fold increase over the price two years earlier. After this the price de-
clined gradually in real terms, due to inflation until late in 1978, when once again the spot market rose in
response to local scarcities on the interruption of Iran’s oil production. Following the lead from the spot
market, OPEC began to move posted prices upwards again.
OPEC AND ITS MEMBERS
- Algeria
- Libya
- Indonesia
- Nigeria
- Iran
- Qatar
- Iraq
- United Arab Emirates
- Kuwait
- Saudi Arabia
- Venezuela
Origins of Oil. Oil and gas are names given to a wide variety of hydrocarbons found in sedimen-
tary basins on or under the earth’s surface. Oil or petroleum is generally a complex mixture of the
heavier (non-gaseous) hydrocarbons, averaging about two atoms of hydrogen to each carbon atom. Oil
found in different reservoirs differs in composition, and many even vary within a single reservoir. Its
properties vary from a light fluid to viscous heavy oil, grading to asphalt.
The process of oil formation started with the mixing of marine organisms with sand and salt to
form sedimentary deposits, in periods ranging from tens of millions of hundreds of millions of years
ago. Continued deposits of material led to burial, with a concomitant rise in pressure and temperature,
resulting in compaction of the sediment into sedimentary rock, called the ‘source rock’, and conversion
of the organic material into hydrocarbons (oil) embedded in the source rock. Increasing pressure from
continued burial, together with the movement of water, with which rock below the water table is satu-
rated, resulted in movement of the small oil globules into the porous and permeable environment of
reservoir rocks. In some situations the oil became trapped in the reservoir rocks by a neighboring layer
of impermeable rock, and these oil bearing reservoir rocks are the sources from which oil is now ob-
tained.
Many types of geological structure can give rise to possible traps for oil. The first, called an
anticline trap is in the form of a dome, in which gas, oil and water are held within the reservoir rock
overlain by a layer of impermeable rock that prevents the oil and gas, more buoyant than the underlying
water, from escaping to the surface. The second type, is called a fault trap, and may occur where imper-
meable rock at a fault in the strata of reservoir rocks prevents upward movement of oil. In the fourth