CHAPTER II

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.