EXPLORATION, RECOVERY, AND TRANSPORTATION 93
the properties of the individual crude oils may cause significant
variations in the properties of the blend over a period of time.
However, the technique of blending several crude oils before
transportation, or even after transportation but before refining,
may eliminate the frequent need to change the processing conditions that would perhaps be required to process each of the crude
oils individually.
The arrival of large quantities of petroleum oil at import and
refining centers has brought about the need for storage facilities.
The usual form of crude oil storage is the collection of large cylindrical steel storage tanks (tank farm) that are a familiar sight at most
refineries and shipping terminals. The tanks vary in size, but some
are capable of holding up to 950,000 barrels of oil. Crude oil may
also be stored in such geological features as salt domes. The domes
have been previously leached or hollowed out into huge underground caves, such as those used by the US Strategic Petroleum
Reserve in Louisiana and Texas. Other underground storage facilities include disused coal mines and artificial caverns. Natural gas
is, on occasion, stored in old reservoirs from which the gas has been
recovered. The gas is pumped under pressure into the reservoir at
times of low gas demand so that it can be retrieved later to meet
peak demand.
Pipelines usually accomplish large-scale transportation of crude
oil, refined petroleum products, natural gas, and tankers, while
smaller-scale distribution, especially of petroleum products, is carried out by barges, trucks, and rail tank cars. In fact, the transportation from the source of the crude oil to the market is as old as the
industry itself. Even the bitumen used in Babylon and other cities
of the Fertile Crescent had to be transported from the seepage at Hit
to the place where it would be used.
In more modern times, the transportation of crude oil from fields
to refineries and of products to market centers was at one time
essentially dependent upon rail transportation. By the early 1970s,
the use of railroad tank cars had diminished to the point at which
only a little over 1% of the total petroleum tonnage was hauled
by the railroads. Pipeline mileage increased to become the major
means of transportation.
There were two principal technological trends during that
period that increased pipeline use: (1) more widespread use was
made of large diameter pipe; and (2) more efficient diesel pumps
became available for installation at stations along the line, replacing
the properties of the individual crude oils may cause significant
variations in the properties of the blend over a period of time.
However, the technique of blending several crude oils before
transportation, or even after transportation but before refining,
may eliminate the frequent need to change the processing conditions that would perhaps be required to process each of the crude
oils individually.
The arrival of large quantities of petroleum oil at import and
refining centers has brought about the need for storage facilities.
The usual form of crude oil storage is the collection of large cylindrical steel storage tanks (tank farm) that are a familiar sight at most
refineries and shipping terminals. The tanks vary in size, but some
are capable of holding up to 950,000 barrels of oil. Crude oil may
also be stored in such geological features as salt domes. The domes
have been previously leached or hollowed out into huge underground caves, such as those used by the US Strategic Petroleum
Reserve in Louisiana and Texas. Other underground storage facilities include disused coal mines and artificial caverns. Natural gas
is, on occasion, stored in old reservoirs from which the gas has been
recovered. The gas is pumped under pressure into the reservoir at
times of low gas demand so that it can be retrieved later to meet
peak demand.
Pipelines usually accomplish large-scale transportation of crude
oil, refined petroleum products, natural gas, and tankers, while
smaller-scale distribution, especially of petroleum products, is carried out by barges, trucks, and rail tank cars. In fact, the transportation from the source of the crude oil to the market is as old as the
industry itself. Even the bitumen used in Babylon and other cities
of the Fertile Crescent had to be transported from the seepage at Hit
to the place where it would be used.
In more modern times, the transportation of crude oil from fields
to refineries and of products to market centers was at one time
essentially dependent upon rail transportation. By the early 1970s,
the use of railroad tank cars had diminished to the point at which
only a little over 1% of the total petroleum tonnage was hauled
by the railroads. Pipeline mileage increased to become the major
means of transportation.
There were two principal technological trends during that
period that increased pipeline use: (1) more widespread use was
made of large diameter pipe; and (2) more efficient diesel pumps
became available for installation at stations along the line, replacing