Petroleum

by Albert Lidgett

Space does not permit my even briefly touching upon the many other oil regions of the world which are now being successfully operated; it is certain, however, as time goes on that their number will be materially increased.

CHAPTER III
HOW PETROLEUM IS PRODUCED

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.