Athabasca - Alistair MacLean Page 0,1

passing of millions of years and the steadily increasing pressures from above gradually changed the decayed vegetation and dead aquatic life into oil.

Described thus simply and quickly, the process sounds reasonable enough. But this is where the gray and disputatious area arises. The conditions necessary for the formation of oil are known; the cause of the metamorphosis is not. It seems probable that some form of chemical catalyst is involved, but this catalyst has not been isolated. The first purely synthetic oil, as distinct from secondary synthetic oils such as those derived from coal, has yet to be produced. We just have to accept that oil is oil, that it is there, bound up in rock strata in fairly well-defined areas throughout the world but always on the sites of ancient seas and lakes, some of which are now continental land, some buried deep under the encroachment of new oceans.

Had the oil remained intermingled with those deeply buried rock strata, and were the earth a stable place, that oil would have been irrecoverable. But our planet is a highly unstable place. There is no such thing as a stable continent securely anchored to the core of the earth. The continents rest on the so-called tectonic plates which, in turn, float on the molten magma below, with neither anchor nor rudder, free to wander in whichever haphazard fashion they will. This they unquestionably do. They are much given to banging into each other, grinding alongside each other, overriding or dipping under each other in a wholly unpredictable fashion and, in general, resembling rocks in the demonstration of their fundamental instability. As this banging and clashing takes place over periods of tens or hundreds of millions of years, it is not readily apparent to us except in the form of earthquakes -- which generally occur where two tectonic plates are in contention.

The collision of two such plates engenders incredible pressures, and two of the effects of such pressures are of particular concern here. In the first place the huge compressive forces involved tend to squeeze the oil from the rock strata in which it is imbedded and to disperse it in whichever direction the pressure permits -- up, down or sideways. Secondly, a collision buckles or folds the rock strata themselves, the upper strata being forced upward to form mountain ranges -- the northern movement of the Indian tectonic plate created the Himalayas -- and the lower strata buckling to create what are virtually subterranean mountains, folding the layered strata into massive domes and arches.

It is at this point, insofar as oil recovery is concerned, that the nature of the rocks themselves become of importance. The rock can be porous or non-porous. The porous rock -- such as gypsum -- permits liquids, such as oil, to pass through them, while the non-porous -- such as limestone -- does not. In the case of porous rock, the oil, influenced by those compressive forces, will seep upward through the rock until the distributive pressure eases, when it will come to rest at or very close to the surface of the earth. In the case of non-porous rock, the oil will become trapped in a dome or arch, and in spite of the great pressures from below can escape neither sideways nor upward but must remain where it is.

In this latter case, what are regarded as conventional methods are used in the recovery of oil. Geologists locate a dome, and a hole is drilled. With reasonable luck they hit an oil dome and not a solid one, and their problems are over -- the powerful subterranean pressures normally drive the oil to the surface.

The recovery of seepage oil which has passed upward through porous rock presents a quite different and far more formidable problem, the answer to which was not found until as late as 1967. Even then it was only a partial answer. The trouble, of course, is that this surface seepage oil does not collect in pools, but is inextricably intermixed with foreign matter, such as sand and clay, from which it has to be abstracted and refined.

It is, in fact, a solid and has to be mined as such; and although this solidified oil may go as deep as six thousand feet, only the first two hundred feet, in the limits of present-day knowledge and techniques, are accessible, and that only by surface mining. Conventional mining methods -- the sinking of vertical shafts and the driving of horizontal galleries -- would be