(all
rights to this material retained by author)
A
Review of the Historic Oil Wells
of
the Little Spokane River Valley
&
Regions
Around
(part
four)
by
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 …
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