Time was when the engineering aspect of the production of petroleum was practically non-existent. The ancients, and even those of the last century, were content to resort to the most primitive means for winning petroleum from the earth. Shallow wells were sunk or dug by hand, the eventual securing of the oil being carried out by lowering primitive receptacles (generally leather bottles) into the hole. It was a period long before the advent of the Oil Age, and the methods employed were clearly in keeping with the mode of life of that day. In practically every oil-producing field of the world—though in this respect the United States is almost an exception—the history records the fact that for many years the extraction of oil from the ground was confined to the use of the primitive methods which held sway in those days—those associated with the operations of the hand-dug wells. In the Far East, notably in Japan, we find the first serious attempts to obtain and utilize petroleum, for as far back as A.D. 615, there were shallow wells in existence, from which the “burning water,” as it was called, was collected. In Roumania and Russia, too, the earlier attempts to create a petroleum industry were confined to these methods.

It was only when the demand for petroleum became large and consistently increased with the opening up of new fields, that we find other and more practical methods were introduced for winning larger quantities of the oil from the earth. To-day, in every branch of the industry associated with petroleum—whether it be in producing the crude oil, in transporting it, or in refining Nature’s product into those numerous commodities which are part and parcel of everyday life—the engineering aspect is one of very great importance. In fact, throughout the petroleum industry, engineering science is the Alpha and Omega. By its means we are now able to carefully study the nature of the ground at depths of 6,000 feet, and to extract from the deep lying strata a wealth of minerals; we are able, too, to transport thousands of tons of crude oil daily across thousands of miles of continent, while is it not the direct result of engineering science which allows over 15,000 tons of petroleum products to be carried across the oceans of the world in one vessel with the same ease that one would take a rowing boat from one side of a lake to another?

Great, however, as have been the degrees of progress recorded in connection with drilling for petroleum, the old methods, generally speaking, and which date back to the days of early China, are still largely copied in all pole and percussion systems of drilling, and though steam has replaced manual labour (and electricity now bids fair to replace steam), the operating principles to-day are the same as then. The only exception, of course, is the advent and growing popularity of the rotary method of drilling, to which interesting phase of the subject I will briefly refer later.

The old Eastern method of drilling has obviously been the forerunner of the Canadian, standard, and other systems of to-day, the wire rope replacing the use of poles. In oil-field work, the principal types of percussion drills used are known (1) as the Pennsylvanian cable, (2) the Canadian pole, and (3) the Russian free-fall system, and though from time to time many attempts have been made to introduce modifications of these, the vast majority have been unsuccessful in their operation.

The Pennsylvanian cable system was used for drilling the earliest oil-wells in the United States, and doubtless took its name from the fact that it was so largely used in that oil region. As may also be gathered from the name, the principal feature in this system is the cable by which the tools are suspended and connected to the walking beam. There is no doubt that this system of drilling, which has been so universally used in the oil-fields, gives most satisfactory results. When first introduced in Pennsylvania, the cable system of drilling was particularly simple, and did remarkably good work, for the reason that the strata usually encountered was of such a nature that it did not cave, and, as a result, the well-pipe was only lowered when the full depth of that string had been drilled. The drilling bits were seldom more than 4 inches thick. In order to give a rotary motion to the bit, the continuous twisting of the cable to and fro was necessary; but when in other fields, where deeper strata had to be explored, the cable system was introduced, the semi-sandy nature of the strata called for wells of larger diameter with correspondingly larger drilling bits. As a consequence of the additional weight of the drilling bit, it was found that the swing of the tools was sufficient to give them a rotating movement for the drilling of a circular hole. In regions where caving-in of the walls of the wells was liable to occur, the string of pipe had to closely follow the tools, which, with the old Pennsylvanian type of rig, meant frequent winding of the cable from the bull wheel, so as to allow of the well pipes being handled.

In order to prevent the waste of time which these operations occasioned, the calf wheel was added, by means of which the pipe could be lowered into the hole without the removal of the drilling cable. This cable almost invariably was of the Manila character, and in many instances this rope is retained to-day, though wire ropes have been introduced frequently.

The Canadian pole system, which is largely in use in oil-field operations, is, like the first-mentioned method of drilling, of the percussion type, the chief essential difference being that, instead of a cable connecting the tools to the surface, poles are used. In former times, these poles were of ash-wood, but with the extended use of the system, iron rods took their place. The introduction of these iron rods was a distinct advantage, for they could be welded to whatever lengths are required, whereas the wooden poles, which were seldom more than 20 feet long, had to be spliced for practical work. The rig used with the Canadian system is not so powerful as that for the Pennsylvanian method, but the one great advantage of the Canadian system is that, for the drilling of shallow oil-wells, it could be operated by men of less experience. The success which has attended the operation of the pole system lies in the fact that although drilling by its means is very slow—for seldom is 250 feet per month exceeded—it is one of the best methods of drilling through complicated strata, and, in the hands of conscientious men, does highly satisfactory work. It might be of interest to very briefly refer to the operations of the system when a well is being drilled. The rig (that is, the superstructure above ground) is quite a simple framing, 70 or more feet high, with a base of about 20 feet. The power is usually derived from a steam engine, with the usual means for operating the gear from the derrick; fuel found locally, natural gas, or other form of heating agent used. One shaft and two spools running in bearings transmit the various motions desired, the drive being taken up by a pulley attached to the main shaft. On this shaft are keyed two band pulleys, which communicate by belting with two spools running immediately overhead in the upper part of the framework. Fastened to one extremity of the main shaft is a disc crank, which, through the medium of a connecting rod, transmits an oscillating movement to an overhead pivoted walking beam. In all systems of percussion drilling, the drilling bit is raised and then dropped a distance of several feet, the result being that the strata to be drilled are steadily pounded away. As the ground is pulverized by the percussion tools, the debris has to be cleared away so as to enable the drill to fall freely and to deliver clean blows to the unbroken strata, and this work is performed by appliances known as bailers and sand pumps. There is no need for me to go into the numerous technical details regarding this or any other system of drilling, for my only desire is to give a general impression as to the usual methods adopted for the winning of petroleum.

I will therefore pass on to deal briefly with the Russian free-fall system so much in vogue in the Russian fields. Incidentally, I may here say that when drilling for oil in Russia, one has to recollect several features which are not common to the development of other oil-fields. Bearing in mind the great depth to which wells have to be sunk to reach the prolific oil horizons in the majority of the fields in Russia, which necessitates starting the well with a very large diameter—frequently 30 inches—it will be easily appreciated that the loss of a hole in the course of drilling is a very expensive affair. The Russian free-fall system of boring necessitates patient and hard manual labour. It is, as its name implies, of the percussion type, and is, in fact, a modified pole-tool system which well suits the local conditions. The clumsy drilling tools have a practically free drop, being picked up when the walking beam is at its lowest point, and released at the top of the stroke. When released, the tools naturally force their way downwards in the strata, and are released only with difficulty, although in a measure this difficulty is minimized on account of the fact that the under-reaming (slightly enlarging the diameter of the hole) is done simultaneously with the drilling.

After a Russian well has been started by means of a slip-hook suspended from a haulage rope, and a depth of some 30 feet obtained, the free-fall is added to the string of tools. This free-fall is composed of two separate parts—the rod and the body—and these are held together by means of a wedge working in vertical slots cut in the sides of the body. In operating the free-fall, the handles, fixed to the temper screw, are held by the driller. On the downward stroke these are pushed forward from right to left, but as soon as the downward stroke is completed, they are quickly pulled backwards. The steel wedge enters the recess and the tools are carried to the top of the stroke, where, by a quick forward jerk, the wedge is thrown clear of the recess, and the tools drop freely, the momentum of the string of tools driving the drilling bit deeper into the hole. After several feet of the hole are drilled, the tools have to be withdrawn in order to allow the pulverized mass of debris to be cleared away, while, owing to the caving nature of the strata, it is necessary to case the well as drilling proceeds.

As I have said, the system is very cumbersome, but, in the hands of experienced men, it does its work well, if but slowly. There are many cases on record where, when the well has assumed a considerable depth, it has been completely spoiled by the carelessness of the operators, but, more often than not, this has been deliberate, for the Caucasian oil-field worker has many grievances, admittedly more or less imaginary.

During recent years, the rotary method of drilling has been successfully adopted, and it is in regard to this revolutionary method of speedy drilling that I will now touch upon. The rotary method of drilling made its dÉbut in Texas some fourteen years ago, and since then it is not any exaggeration to say that nearly 20,000 wells for oil have been drilled with the system, which has found popularity in all the oil-fields of the world. Its main operation is simplicity itself: a rigid stem of heavy pipe rotates a fish-tail drilling bit at the bottom of the hole, cutting and stirring up the formation to be drilled. It cuts its way through the underground formations, much in the same way as a screw when rotated forces its way through wood. It is the essence of speed in drilling, for, unlike the necessary principles to be adopted in the percussion methods of drilling, the rotary drill does not have to be lifted from the hole for the purposes of clearing. The pulverized strata are continuously washed from the hole by a stream of water reaching the bottom of the drill. Very frequently, a pressure-fed mud is used, and this serves a double purpose, for in its return to the surface it tends to plaster the walls of the well. The mud emerges in streams of high velocity from the two apertures in the drilling bit (for in its downward course it is carried through the drilling pipe or stem), but naturally loses this velocity considerably in its return to the surface. It is, however, very easy to detect the kind of stratum being drilled through from the returned cuttings, these reaching the surface but a few minutes after the drilling bit has entered the formation.

From time to time various grievances have been ventilated against this improved system of boring for petroleum, but to-day its adoption is world-wide, and by its use wells which, with the old-fashioned method of drilling would take many months if not two or three years, are now got down to the producing horizons in but a few weeks. It is, in fact, solely due to the ever-increasing use of the rotary drill that the universally increased demands for petroleum products have been met by an ever-increasing production of the crude oil.

Leaving the question of drilling methods, I cannot fail to mention the interesting fact that in oil-field operations progress is now being recorded in another direction, and that is by the increasing utilization of electrical power in the place of steam. At the time of writing, it is safe to say that fully 60 per cent. of the power requirements on the oil-fields is provided for by steam plants, with their attendant waste. Oil and gas engines, with their greater efficiency, may claim to be operated to an extent of 35 per cent., while not more than 5 per cent. of the requirements are satisfied by the use of electric motors. There is no doubt that prejudice has had a deal to do with the very minimized use of electrical power on the oil-fields in the past, but this is being gradually swept aside, and, in the next few years, I have no doubt that both electrical manufacturers and the petroleum industry generally will materially benefit from the use of this cheap and very economical form of power. In the past, many disastrous oil-field conflagrations have been due solely to the use of open-fired engines in close proximity to the wells, but with the use of electrical energy this fire danger will be rapidly removed.

Before closing this chapter, I would say a word or two with respect to the bringing into the producing stage of the oil-wells when once they have been drilled. In the early history of oil-held developments, it was not infrequent to find the crude oil ejected from the well by natural pressure, but to-day it is the exception to find those oil-fountains which have made the early history of the Russian oil-fields so famous. In many of the fields, explosives are used to promote the flow of oil, and when the well “comes in” to production, the ordinary methods of bailing or pumping are resorted to. Compressed air is also used for bringing about and sustaining production. The quantity of air and the periods of admission naturally vary with the diameters of the wells, the amount of gas present, the level of the liquid, etc., which latter also determines the pressure of air necessary.

The natural exhaustion of oil-wells can obviously have no remedy, but areas conveying that impression can often be revived by methods, the study of which is being carefully continued. As I write, I find that the officials of the United States Bureau of Mines, who have been studying this question of exhaustion, have arrived at the conclusion that from 20 to as much as 90 per cent. of the crude oil remains in the strata tapped by the well, even when it is abandoned as no longer capable of profitable production. This conclusion opens up what may prove some day to be a most interesting chapter in oil-field history.