Athabasca. Alistair MacLean
the cause of erosion, the end result is the same: the rock is reduced to its tiniest possible constituents – rock particles or, simply, dust. Rain and melting snow carry this dust down to the tiniest rivulets and the mightiest rivers, which in turn transport it to lakes, inland seas and the coastal regions of the oceans. Dust, however fine and powdery, is still heavier than water, and whenever the water becomes sufficiently still, it will gradually sink to the bottom, not only in lakes and seas but also in the sluggish lower reaches of rivers and, where flood conditions exist, inland in the form of silt.
And so, over unimaginably long reaches of time, whole mountain ranges are carried down to the seas and in the process, through the effects of gravity, new rock is born as layer after layer of dust accumulates on the bottom, building up to a depth of ten, a hundred, perhaps even a thousand feet, the lowermost layers being gradually compacted by the immense and steadily-increasing pressures from above, until the particles fuse together and re-form as new rock.
It is in the intermediate and final processes of this new rock formation that oil comes into being. Those lakes and seas of hundreds of millions of years ago were almost choked by water plants and the most primitive forms of aquatic life. On dying, they sank to the bottom of the lakes and seas along with the settling dust particles and were gradually buried deep under the endless layers of more dust and more aquatic and plant life that slowly accumulated above them. The 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 grey 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 embedded 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 upwards 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 becomes of importance. The rock can be porous or non-porous, the porous rock – such as gypsum – permitting liquids, such as oil, to pass through them, while the non-porous – such as granite – does not. In the case of porous rock the oil, influenced by those compressive forces, will seep upwards 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 upwards 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 upwards 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 hopelessly inadequate, as they would provide only the tiniest fraction of the raw material required to make the extraction process commercially viable. The latest oil extraction plant, which went into operation only in the summer of 1978, requires 10,000 tons of raw material every hour.
Two excellent examples of the two different methods of oil recovery are to be found in the far north-west of North America. The conventional method of deep drilling is well exemplified by the Prudhoe Bay oilfield on the Arctic shore of northern Alaska; its latter-day counterpart, the surface mining of oil, is to be found – and, indeed, it is the only place in the world where it can be found – in the tar sands of Athabasca.
“This,” said George Dermott, “is no place for us.” He eased his considerable bulk back from the dining-table and regarded the remains of several enormous lamb chops with disfavour. “Jim Brady expects his field operatives to be lean, fit and athletic. Are we lean, fit and athletic?”
“There are desserts,” Donald Mackenzie said. Like Dermott he was a large and comfortable man with a rugged, weatherbeaten face, a little larger and a little less comfortable. Observers often took him and his partner for a pair of retired heavyweight boxers. “I can see cakes, cookies and a wide variety of pastries,” he went on. “You read their food brochure? Says that the average man requires at least five thousand calories a day to cope with Arctic conditions. But we, George, are not average men. Six thousand would do better in a pinch. Nearer seven would be safer, I’d say. Chocolate mousse and double cream?”
“He had a notice about it on the staff bulletin board,” Dermott said wryly. “Heavy black border, for some reason. Signed, too.”
“Senior operatives don’t look at staff boards,” Mackenzie sniffed. He heaved his 220 pounds erect and headed purposefully for the food counter. There was no doubt that B.P./Sohio did extremely well by their staff. Here at Prudhoe Bay, on the bitter rim of the Arctic Ocean in midwinter, the spacious, light and airy dining-room, with multi-coloured pastel walls back-dropping the recurrent five-pointed star motif, was maintained at a pleasantly fresh 72 degrees by the air-conditioned central heating. The temperature difference between the dining-room and the outside world was 105°F. The range of excellently-cooked food was astonishing.
“Don’t exactly starve themselves up here,” he said as he returned with a mousse for each of them and a pitcher of heavy cream. “I wonder what any of the old Alaskan sourdoughs would have made of it.”
The first reaction of a prospector or trapper of yesteryear would have been that he was suffering from hallucinations. All in all, it was hard to say what feature he would have found the most astonishing. Eighty per cent of the items on the menu would have been unknown