Man's physical universe

xanabras

"BETTER THINGS" FROM PETROLEUM 697

Research has decreased the cost of gasoHne.

The average servicestation

price of gasoHne in 1920, minus taxes, was 29.7 cents per

gallon, while it had been reduced to 13.4 cents per gallon by 1939.

Modem Petroleum-prospecting Is Scientific.

During the 17 years starting with 1922, 1183 new oil fields were

discovered, 796 of which were major pools estimated at more than

1,000,000 barrels of recoverable oil each. Of these 796 major pools,

746 were discovered by geological and geophysical methods, thus

leaving only 50 pools to the credit of random drilling or "wildcatting."

The newer tools of geophysics include seismography, the torsion balance,

the gravitometer, the magnetometer, and the electric log.

Geochemical methods, by which samples of soil are analyzed for waxes,

oil, and hydrocarbon gases and which are so sensitive that a few parts

of ethane per billion may be determined, are now coming into vogue.

The mass-spectrograph of the physics laboratory is the modern

geochemical divining rod. Analyses may be made on samples of gases

smaller In volume than the head of a pin, and the results may be

obtained within ten minutes.

Seismographic exploration uses sound waves from test explosions

sent down through one stratum after another and recorded as they

bounce back. From these data underground configurations are plotted

and the possibility of oil-bearing structures determined.

Another modern device is an electric eye which is very sensitive to

gamma rays. It is lowered into a well, where it responds to varying emissions

of gamma rays from different strata, thus helping to identify them.

Twenty years ago wells cost about $10,000 each and went down

only 2000 to 3000 feet.

Now wells may cost $150,000 or more and

frequently are drilled to a depth of from 8000 to 15,000 feet.

Many Improvements Have Been Made in the Manufacture of Motor

Fuels and Lubricants.

About half of the gasoline produced today comes from the cracking

of petroleum. This gasoline possesses antiknock properties, so that

the octane number *

of the average gasoline not treated with tetra-

1 Octane number — In the standard method for rating the antiknock value of gasoline,

iso-octane,

CH3

CHs

CHs—CH—CHi—C—CH3

CHa

is arbitrarily assigned the value of 100, while normal heptane, CH3— CH2 — CH2 — CH2 —

CH2—CH2—CH3, is given the value of 0. The percentage of iso-octane that has to be

mixed with heptane to reduce the intensity of the knocking of the mixture to that of the

gasoline is called the antiknock rating or, preferably, the octane number.

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