(all rights to this material retained by author)
A Review of the Historic Oil Wells
of the Little Spokane River Valley
Wally Lee Parker
… whatever one finds beneath …
Since science is by its very nature an argumentative and confrontational process, the acceptance of the organic hypothesis for the creation of oil — the theory that oil is the highly altered remains of once living plants and animals — historically was and on occasion still is challenged. Sometimes these challenges are derived from legitimate questions regarding the validity of contemporary scientific convention, and sometimes they’re nothing more than uniquely self-serving promotional efforts clearly intended to support a specific proposal to drill into what mainstream theory assures us is totally inorganic bedrock — or to depths generally assumed to be barren of oil. Often these promotional efforts, both historic and contemporary, will follow a line of argument suggesting that while the current theory of oil formation is not wrong, oil can also be produced through inorganic processes that mainstream science has discounted, and that a few dollars and a little faith invested into whatever venture is being proposed will most certainly tap into that endless sea of oil impounded just below the depths so far plumbed — oil often characterized as being of a type heretofore unknown to science.
Mainstream petroleum geologists are primarily interested in sandstones from the Paleozoic and Mesozoic — a layered set of extensive geologic eras beginning approximately 542 million years ago and ending about 65 million years ago. Most of the world’s known reserves of oil were formed somewhere within this large slice of geologic history.
The above noted sandstones are a granular type of sedimentary rock sometimes having enough space between individual grains to harbor minute drops of oil. As a result, most oil reserves are found within these types of rock.
As for where the oil itself originated; in 1883 Professor Joseph Le Conte of the University of California published a book titled Elements of Geology. Regarding the origin of petroleum and coal, he wrote, “The most probable view seems to be that both coal and petroleum are formed from organic matter, but of different kinds and under slightly different conditions — that coal is formed from terrestrial vascular plants, in the presence of fresh water, while … petroleum … (is) … formed from more perishable cellular plants and animals, in the presence of salt-water.”
Twenty five years later, in 1908, United States Geological Survey Bulletin #335 noted that though “The prevalent scientific opinion is in favor of the organic theory,” there was still a group proposing that oil might be “… of inorganic origin, having been formed by the chemical action of water on the formerly un-oxidized mineral constituents of the rock.”
The basics of oilfield geology were clearly laid out by Paul M. Paine and B. K. Stroud in their 1913 volume Oil Production Methods when they stated, “It is now a well-established fact that practically all petroleum is obtained from sedimentaries (sedimentary rock) and that the major portion is derived from the sands and sandstones, and that these productive measures (productive layers) are usually overlain with a so-called cap rock. The cap rock is an impervious layer of clay, shale, or some other compact material, which prevents ascension (the migration upward) on the part of the gas and oil into higher strata …”
As for how these strata were originally deposited, the assumption is that materials eroded from the land were transported by relatively fast moving rivers to the oceans, where, on encountering slower waters, they settle.
“It is evident … the disposition will not be uniform, but that the coarser and heavier bodied will sink first, leaving the finer particles in a longer period of suspension. For this reason sands and gravels imply shallow water disposition while the more comminuted materials that form the shales and clays remain in suspension and are transported farther from shore so that they are deposited at greater depths and in more quiet waters. In the course of time these become covered with further depositions, the weight of the overlying strata caused the lower measures to become more compact and rock-like, and there are built up wide bodies of strata horizontally placed, or with only a slight inclination. During this period the shore line may advance and retreat many times, so that what was deep water becomes shallow, resulting in a bed of sand being deposited on top of a layer of clay, and vice versa. Eventually the constant effort of the internal forces at work in the earth’s interior may alter the position of the entire mass, or portions of it, and tangential stresses may distort it by causing it to crinkle and bend into arch-like folds.”
These sediments can be extremely rich in organic debris derived from the cyclic blooms of minute plants and animals living and dying within the mineral rich water. This organic debris, settling as muck intermixed with the sand and clay, is what will eventually become oil.
Once solidified into the earth’s crust, these horizontal deposits can be distorted by ongoing crustal stresses. If the deposits are compressed from one or two sides, they tend to fold. “Anticline is the name given to the arch-like position taken by strata when they have been folded. The corresponding position of strata when they are bent down and then up is known as a syncline, and frequently the crinkling in the earth’s crust that has brought about the folding structure has resulted in a series of wave-like alternating anticlines and synclines.”
Paine and Stroud’s description of the sedimentary process is also a classic description of the rock strata found in the classic oil field. On the way down, oilfield drills tend to pass through successive layers of sandstone and shale just as described. Since each layer of sandstone would normally be expected to contain only a small amount of oil, geologist look for areas in which the originally level — horizontal — rock structures have been folded — inclined — into Paine and Stroud’s “arch-like folds.” The ability of gases and fluids to migrate through the sandstone within such folds also allows them to collect in discrete layers once the once horizontal sandstones have been tilted.
The force impelling this migration within anticlines is described as a tendency “in the course of time to separate according to (the) respective specific gravities” of the substances involved. “The gas rises to the topmost point available while the water, if such be present, displaces the oil by reason of its greater weight. Thus there are three fairly well-marked zones, first the gas, then the oil, and finally at the bottom the water.”
In other words the experience of drilling, and the record keeping involved, allowed early oil prospectors to begin diagramming out the geology of oil fields. In the case of oil, often the experience came first, and the theory second. The assumption derived from experience was that oil was most likely to be found where the geology was similar to what had been previously seen. But with geology, the problem is seeing what is hidden.
In any vertical slice of the earth’s crust — a river-cut canyon wall of sedimentary rock for instance — the rock at the bottom of the wall should be older than the rock at the top. Since geology is an active process, there are exceptions. Over geologic ages rocks can be twisted and folded and sometimes even doubling over on themselves so the oldest are on top. Younger materials heated or wetted into plasticity can sometimes be pressure injected into cracks and crevices in older rocks — filling the cracks and crevices to form discontinuous geological features referred to as dikes. And of course erosion can gnaw away entire ages of rock. So even if the sequence of disposition is correct, new sediments or flows over the top of these eroded exposures can give the assumption of continuity while leaving vast gaps in the record. Despite all this, as a general rule, if you want to see back in time you need to look deeper beneath the surface, or find areas where the once deeper rocks have been exposed at the surface.
Also, growing consensus within early geology settled toward the idea that coal and oil, though related in so far as both being derived from once living organisms, were produced through differing geological processes. Since the geologic history of any given region is central in determining that area’s potential as a repository for oil, coal, and natural gas, by reading the specifics of the local geology it should be possible to surmise the likelihood that any kind of fossil fuel can be found — and which type of fuel the local geology is likely to produce. The fault in all this is that before such a determination can be made, the local geologic history has to be visible.
The easiest determination for coal is when seams are seen at the surface. Oil seeps are often evidence of something more below ground. And flammable gas bubbling up is a clear indicator of underground activity of some sort. Lacking these — and keeping in mind that “salting” of oil seepages is at the root of many oil scams, while bubbling natural gas most often proves to be common “swamp gas” rather than petroleum or coal gas — geologist usually begin searching for fossil fuels by determining the age and structure of the visible rocks around.
The classic fundamental in determining geologic age in sedimentary materials – and oil with rare exception is found in porous sedimentary materials – is that the deeper one goes in the deposit, the older the deposit is. Simply put, since sedimentary disposition is something that occurs on the top, what’s on top is younger than whatever one finds beneath.
… to be continued …