WHAT IS PETROLEUM?
Petroleum, or to use its comprehensive colloquial synonym, “oil,” has
come to play such a widespread part in every-day life that most people,
the younger generation especially, take its existence for granted
without further enquiry. Few pause to reflect that this basic essential
of modern commerce is a comparatively new agent for the service of
mankind. Its applications are so manifold that it is now recognized as
indispensable; whereas in a period so recent as that of the advent of
Lincoln in American history it was almost negligible as a contributor
to the nation’s wealth and productive power. The development of
petroleum ranks third among the three great discoveries in the realm of
applied science which have revolutionized industry in the past hundred
years--the other elements being electricity and steam. In company
with electricity, it has effected changes in methods of manufacture,
and added to the comforts of civilization in ways that it would take
volumes to relate. It has been a factor in revolutionizing warfare--as
the recent great conflict proved--and it is essential to the arts of
peace.
Like electricity, with which its development as a servant of man has
been coincident, its utility consists in the fact that it is a source
of light, heat and energy. But unlike electricity it is a passive as
well as an active agent. For illustration, the same motor car which
is propelled by one product of crude petroleum is also lubricated and
enabled to travel by means of another product of the same commodity.
Petroleum is the latest of the earth’s riches which man has learned
to adapt to his needs. The use of iron, for instance, goes back to
prehistoric times, and the same is true of nearly all metals, precious
and otherwise, of salt and many other of our mineral products which the
chemistry of creation has provided in the crust of this terrestrial
sphere. But for countless centuries man went his way knowing of the
existence of petroleum, yet utilizing it only in a sporadic and
casual manner, until American ingenuity and adaptability--working in
coöperation with scientists of other lands--made it the marvelous
agent that it is to-day. And all this has happened since the
grandfathers of most of the younger generation of the twentieth century
were born.
The word petroleum comes from two Latin terms signifying “rock” and
“oil”. “Rock-oil,” which was an early name given it on this continent,
is accounted for by the fact that certain shales and coals possess oil
as part of their constituents. It is one of the family of bitumens,
which even in their natural state assume many forms. In its commercial
sense the word “petroleum” is a generic term covering the whole
group of hydro-carbons--the refined or manufactured products as well
as the crude oil. But as yet scientists are divided in opinion as
to its origin and the extent of the world’s supply. All we know is
that it is diffused over almost every section of the earth, and that
new deposits--on the scientific development of which geologists are
constantly at work--are ever being discovered.
One school of scientists holds that it is of inorganic origin, derived
from metallic carbides lying below the porous strata which serve as
Nature’s reservoirs for the crude product that is “mined” by the
modern oil producer. But the more widely accepted view is that crude
petroleum is of organic origin, born of either animal or vegetable
matter embedded in the earth’s surface, which in the process of
decay or transmutation has taken this form. Travellers state that in
the neighbourhood of the Caspian Sea the conversion of such organic
matter into petroleum is visibly in operation to-day. The British
scientist, Sir Boverton Redwood, in explaining the natural process
by which petroleum came into existence, has pointed out that in the
comparatively deep and quiescent water along the margin of the land
in past there would be abundant opportunity for the accumulation of
deposits of the remains of marine animals and plants, as well as of
vegetable matter from the land, borne down to the coast by water
courses. The changes which the world has undergone would result in the
burial of these accumulations under sedimentary strata, during the
process of creating land where once was water.
During geological ages different parts of the earth’s surface have
alternately been raised and submerged. When above sea level they have
been at times subjected to disintegration and removed by such agencies
as water, wind, and glaciers, and when submerged the same localities
have received deposits, as we now see being made under the ocean and
at the mouths of rivers. As all the geological formations which are
stratified have been deposited in their respective localities while
that part of the earth’s surface was under water, and as oil is, almost
without exception, found in these formations, we are able to account
for the fact that petroleum is frequently discovered in localities
which are now at a great distance from the sea. It would also explain
why oil is frequently found in association with salt--a circumstance
which had its accidental bearing on the earlier development of the
petroleum industry in the United States. Many other arguments have been
adduced supporting a belief in the vegetable origin of petroleum that
would be worth discussing at length, were this a scientific treatise.
Much controversy still prevails. The holders of the inorganic theory
who assume that petroleum could be formed by chemical reactions from
minerals are for the most part chemists who base their conclusions
on laboratory experiments; whereas the scientists who hold by the
organic theory are geologists, who base their contentions on actual
investigations of the earth’s crust and the records of its changes as
written in the rocks.
The assumption is that the organic matter, after being imprisoned in
the sedimentary rock by the processes indicated, under the influence
of heat and pressure in some cases assumed the form of coal; in other
instances succumbed to decay; while in other cases it formed crude
petroleum and gas. It is assumed that a mere fraction of the organic
matter which was gradually imprisoned in the formation of sedimentary
rock would have been sufficient to create incalculable stores of
oil and gas. The mode of decomposition by which these elements were
generated is one of Nature’s secrets; and the stage in the history of
oil-bearing rock in which the necessary chemical transformation took
place is equally a matter of conjecture. As has been said, the presence
of salt is a prevalent phenomenon in connection with oil deposits the
world over. Not only is a strongly saline water commonly present in
the vicinity of petroliferous rock, but in a number of fields oil is
closely connected with large masses of rock-salt, gypsum and dolomite.
An important fact which makes definite conclusions difficult is that
in its world-wide distribution petroleum is to be found in almost the
whole range of strata which forms the earth’s crust; from the earliest
or Laurentian rocks to the most recent formations of what is known in
geology as the Quarternary period.
It is, however, evident that oil has often moved from the formations in
which it was made to other formations, generally loose or porous, which
have served as natural reservoirs for storing the oil in the earth.
It is probable that in most instances the migration took place by
filtration or flowing through fissures or openings from one formation
to another, while in some cases it is evident that a distillation took
place and the migration probably was made in the form of vapor, which
was ultimately condensed in a cooler formation and there stored.
Generally speaking, however, it reveals itself in commercial
quantities chiefly in the Devonian and carboniferous formations which
are comparatively old; or in the Tertiary rocks, aeons younger in
geological evolution. The geographical distribution is as diverse as
the geological; the deposits in many instances occur along well-defined
lines and in association with mountain ranges, though this condition is
by no means axiomatic. It is assumed that in the elevatory processes
which obviously occurred while the earth’s crust was attaining its
present characteristics, certain folds were formed which arrested and
collected the oil in productive belts.
Early misapprehensions with regard to the origin of petroleum are
indicated by the familiar word “coal-oil,” now used to signify one
of the most popular products of crude petroleum; but originally
derived from the fact that what we now know as kerosene or lamp oil
was produced from the distillation of coal before petroleum became an
important source from which the lamp oil was obtained. Over a century
ago miners in Shropshire, England, observed oil trickling from fissures
in coal veins and assumed that coal was the source of the liquid.
This belief was intensified by the fact that the earliest discoveries
in Pennsylvania, which resulted in the creation of the great modern
petroleum industry of the United States, were in the vicinity of
vast deposits of bituminous coal. Shortly afterward this belief was
disproven by the discovery of valuable oil fields in the western part
of the province of Ontario, Canada, where no coal exists; and other
discoveries on this continent and elsewhere have furnished abundant
proof that oil may exist in large volumes independently of coal.
In considering the two primary theories as to the origin of petroleum,
whether inorganic--that is from chemical action on rocks forming part
of the earth’s crust, or whether organic, from the decay of vegetable
and animal matter--there are many strong arguments for both theories
and it is quite reasonable to believe that both may be correct. There
are localities where petroleum exists in formations showing little
evidence of animal or vegetable remains and little possibility of
having reached these formations by migration. As a rule, the production
in such formations is small, rarely in commercial quantities, and it is
probably derived from inorganic sources. This possibility is further
demonstrated by laboratory experiments.
On the other hand, it is probable that the greatest sources of
petroleum are due to organic origin, more particularly in the
carboniferous or the tertiary formations, where coal, cannel-coal,
lignite, and other similar products are most frequently found.
Hydro-carbons identical with most of the products of the distillation
of petroleum, are so commonly obtained from the distillation of coal,
lignite, and even bituminous shale and peat that in most cases the
organic theory of the source of petroleum appears to be the correct one.
Natural gas usually exists in association with oil deposits and in a
great measure has the same properties, its existence as a gas or a
liquid being dependent on the temperature and pressure under which it
is held. In recent years, before it is sold for consumption as natural
gas, it has become the general practice of oil producers to compress
and chill the gas to obtain a considerable yield of gasoline which
exists in the natural gas as a vapor. Another process for extracting
this gasoline is by absorption, that is, passing the gas under a
comparatively low pressure through a heavy oil, which takes out a part
of the gasoline from the gas. In both processes, but especially in the
high compression system, there is a considerable percentage of very
volatile gasoline obtained, which is highly explosive and difficult to
retain as a liquid. Varying in different localities and under different
conditions, natural gas yields commercially from one-half gallon to
five gallons of gasoline per thousand cubic feet, although extreme
cases show much wider range.
Natural gas, in conjunction with hydraulic pressure, is the cause of
what is known to oil operators as a “gusher” or flowing well. It is the
compression and volatility of the gas imprisoned for ages in the rock
that sends the oil spouting into the air and has been known to create
a flow of 170,000 barrels in a single day. As a general practice, and
probably due to the weight of overlying strata, the pressure of gas
encountered in drilling into oil formations is proportional to the
depth. This pressure is generally known as rock pressure and the flow
of the wells is in part due to it. A principal factor in the production
of oil or gas is the nature of the formations from which the production
is derived--their thickness and porosity.
In some cases, notably in Mexico, the flow seems to be caused by the
action of water. Here the formations are very porous, opposing little
obstacle to the flow of the oil and gas through the formation. The
production from the wells under these conditions is very great and,
unlike most wells, a gradual decline in the yield is unusual, there
being little sign of exhaustion until the moment when the well begins
producing salt water in increasing proportions. After the appearance
of the salt water the production of oil diminishes rapidly and for
practical purposes soon ceases, due to the small production of oil and
the fact that it comes out as an emulsion with the water, which is very
difficult to utilize.
A characteristic of the Mexican wells is that the oil, and finally
the salt water which follows it, are generally produced at a high
temperature--from 115 to 145 degrees. Such gushers originally produced
another fallacious belief that oil exists in subterranean pools or
reservoirs; but investigation has shown that oil has been preserved in
the rocks in a way somewhat similar to that in which water is retained
in a sponge. A typical piece of oil rock examined under the microscope
reveals millions of tiny interstices between different grains of sand.
Porous, oil-bearing sandstone may contain one-tenth or one-eighth
of its bulk in petroleum. The term “oil sands” is common in the oil
industry and refers to the type of coarse grained porous rock which
forms the best reservoir for petroleum; but limestone and some of the
rocks described by geologists as conglomerates sometimes serve the same
purpose. In every instance the oil-bearing stratum has been covered by
a layer of non-porous rock, whose impervious qualities keep the oil and
gas imprisoned until penetrated by the drill. Surface deposits are also
a well-known phenomenon; and were the only type of deposits known to
the world until modern times. About them has grown up much interesting
history and legend which will be dealt with in a subsequent chapter.
The geographical distribution of petroleum is, as has been said,
world-wide, and the oil prospector, followed by the capitalist, who
make these discoveries available to the world, are constantly opening
up new fields. Oil discoveries necessarily mean great commercial
expansion for the localities in which they occur; and no small part
of the enormous wealth of the United States has resulted both from
the abundance of our deposits of crude, and from the manifold uses to
which they have been applied in the improvement and standardization of
manufacture. Though the United States is the greatest oil producing
country in the world, production on modern commercial and scientific
lines first began across the seas, in the little Kingdom of Roumania.
There the industry in a modern sense had its birth in 1857. The United
States entered the field by virtue of the Pennsylvania discoveries
in 1859, and the original industry has attained enormous proportions
through later discoveries in such scattered portions of our country as
California, Oklahoma, Wyoming and Texas. Italy was the third entrant in
the field of organized production in 1860, but her industry has never
assumed large proportions. Other countries became producers in the
following order: Canada, Russia, Galicia (then Austrian, now Polish),
Japan, Germany, India (Burma), Dutch East Indies, Peru and Mexico.
The Mexican industry dates back only to 1907 and that country is now
recognized as one of the world’s greatest fields.
In the United States when we speak of benzine, gasoline and naphtha
we allude to the more volatile distillates of petroleum. Lamp oil,
as it is called in England, and kerosene or coal oil, as it is known
in America, constitutes another product. While petroleum refining is
conducted primarily for the production of motor fuel, illuminating oil,
lubricants, wax, gas oil, and fuel oil, of various grades, there are a
host of specialty products obtained from petroleum which go into use
in almost every phase of human activity. These include pharmaceutical
preparations for internal and external use, in the form of medicinal
oils, ointments, salves, and soaps; cements, including binders for
briquetted fuels, water-proofing and saturating agents; special
solvents, used to some extent in all chemical laboratories; and an
imposing list of rare chemicals, such as higher alcohols of the nature
of fusel-oil, and a large variety of organic sulphur compounds.
The word “naphtha” comes from Russia, where it is applied to all crude
petroleum, and was supposedly derived from the Persian, nafata, to
exude. Early Roman writers like Strabo and Pliny, who were acquainted
with the burning and lighting properties of the surface oil deposits
known to the ancients, spoke of it as bitumen and liquidum candidum.
And other terms in Roman and Greek literature obviously signify the
same substance.
Additional designations are: Ropa, ropianka, (Galician Polish) pacura
(Roumanian), Huile de naphte and pétrole brut (French); erdoel, rohoel,
rohnaphtha (German); yenan (Burmese); sekinoyn (Japanese) shi-yu
(Chinese); chapapote (Mexican).
There are also a large number of names for such petroleum products as
paraffine, or mineral wax, of which the Spanish brea is an example; and
for asphalt, which is really petroleum in a dense form.
Surface indications of petroleum and natural gas are frequent and
diversified. The most common is in the nature of seepages, which are
generally found in what are geologically highly disturbed areas,
underlain with petroleum deposits. These seepages most frequently occur
where the oil-containing formations have been folded and exposed on
the surface, either when the folding took place or subsequently through
the cutting of water courses. From these formations the oil seeps out
and is shown as a coating on the streams or, in case the quantity is
great or the oil very heavy, it is shown as asphalt deposits, of which
there are many in Mexico, and of which the best known are the pitch
lakes in Trinidad and Venezuela.
It is a common occurrence in oil fields, more particularly those in the
younger geological formations, to find mud volcanoes, probably caused
by the escape of gas, bringing with it some water, which reaches the
surface as mud. These mud volcanoes vary from a foot or two to several
hundred feet in height in different localities and frequently cover an
area of several acres.
Another evidence of petroleum is found in Galicia in the form of
ozocerite, which is in many ways similar to paraffin, but has some
distinctive characteristics. This ozocerite is found on the surface
or in mines. It exists in nature frequently in the form of lumps of
several pounds of weight and more commonly impregnating the shale from
which it is removed by boiling and removed as a scum on the boiling
water.
[Illustration: A temporary oil reservoir in Oklahoma. When petroleum is
produced in advance of the erection of tanks it is held by earthen dams]
Petroleum is found in different parts of the world and even in
different formations in the same locality with widely different
properties and composition. In some cases the oil is found almost white
and varies through all the shades of amber and brown to black. It is
found as highly liquid as gasoline and with a viscosity such that it
will hardly run away from the hole--almost as viscous as the asphalt
used for pavements.
It is also interesting to note that the crude oil from different
localities, and even from different formations in the same locality,
not only varies greatly in its own properties, but the manufactured
products derived from different grades have very different properties
as well. From some crude oils special lubricating oils can be made
which cannot be manufactured from other oils. The same is true of
the paraffins derived from different oils, some, for example, being
especially desirable for one purpose while paraffin derived from
another crude is more suitable for another purpose, due to its
different properties and action under treatment. Thus, the refined oils
from different crudes show a great variety, some lamp oils possessing
much greater illuminating power than that derived from other crudes
and this not due to the method of manufacture but to the actual
difference in the properties of the refined oil derived from the
different crudes.
In Roumania and Russia the wells produce enormous quantities of sand
with the oil, particularly when they first start flowing. The Roumanian
wells frequently start flowing sand as fine as flour and more like the
dust of a country road. This sand may hardly smell of oil at first
and at this stage it covers the ground like a volcanic ash, sometimes
breaking in the roofs of neighbouring houses.
In the course of a few days the sand begins to show more oil but piles
up around the mouth of the well, giving it the appearance of a small
volcano. As the quantity of oil increases it reaches a stage where
the oil and sand will flow away from the well together and the oil
is settled out in dams before being pumped to the tanks. Later, the
percentage of sand becomes less until it is almost negligible.
The action of the sharp sand is similar to that of a sand blast,
necessitating much ingenuity in changing the pipes and valves for
handling the well while it is flowing.
The diversity that is characteristic of petroleum in its geological and
geographical distribution, and in its adaptability to the needs of
humanity, is also to be found in the nature of the crude oil deposits.
It differs in colour, density and other qualities in almost every
field. In America, with which this book chiefly deals, three distinct
basic types are recognized; the mixed base (paraffine and asphalt in
combination) found in Ohio, Oklahoma and other States; the paraffine
base, which is characteristic of the paler crudes of Pennsylvania and
West Virginia; and the asphalt base common to the fields of California
and Texas. The special qualities of the crude fix in a large measure,
the character of the products each yields when subjected to refining
and manufacturing processes.