Albuquerque citizen., 1907-08-19
new BULLETIN
INTERESTS
OIL MEN
Scientific Work Is of Unusual
Benefit to That
Industry.

Washington. d. c., August ia
knowledge of the conditions that gov
ern the accumulation of petroleum
in pools is of the greatest practical
value to the oil men, and investiga-
tions to determine these conditions
have been carried on for a number
of years by the geologists of the
United States geological survey in
various oil-producing districts The
results of some recent work of this
kind in Pennsylvania, Ohio and West
Virginia, by Messrs. w. It. Griswold
and NJ. J. Mum, have just been pub
lished by the survey as Bulletin No.
31S.
The investigation of Mr.. Griswold
and Mr.. Mum involved the solution
of two important questions: First
what are the physical laws under
which oil accumulates in pools; and
second, how many of the conditions
of this accumulation can be deter
mined prior to actual test by the
drill. The area selected for study
was that portion of the Appalachian
oil field comprising the Steubenville
Ohio-West Virginia and the Bur-
gettstown and Claysvlle Pennsyl-
vania, quadrangles, within which lie
most of the white oil-producing
sands of the Appalachian field. This
area, about $50 square miles in ex-
tent, has been tested by numerous
wells and includes large and impor-
tant developed oil pools from the
Berea, the Hundred-Foot, the Cor
don, the Fourth and the Fifth sands.
Records of the conditions discovered
by the many test wells were collect
ed and a map of one of the prin-
cipal oil-producing sands in each
quadrangle was drawn to represent
the sand as If all of the material
above it had been removed and its
upper surface exposed to view. From
l. Ia 1,tr
applicable to the different oil accum-
ulations have been deduced.
Oil Accommodations.
The chief factors in the accumula-
ton of oil are the geologic structure
of the oil-bearing rocks and the salt
water contained in the different pro-
ducing sands. These sands vary
greatly in the extent of their satura-
tion with salt water. The younger
sands or those nearer the surface,
comprise much larger areas that are
completely saturated, and the satura-
tion decreases downward with each
succeeding sand. The fifth, the deep
est sand from which oil has been
produced within the region, contains
salt water only in very small areas
in the very lowest spots.
The oil has accumulated in differ
ent places with reference to the high
and low points of the rocks, the
place of accumulation depending up
on the quantity of salt water contain
ed in the sand rocks. In those sand
stones that are completely saturated
the oil is found on high places;
where the oil sands contain water
only up to a certain height around
the side OF a structural basn-as If
it were a bowl half filled with water
the oil lies at the top of the water
and extends around the basin in
lines at the same elevation, following
ctffl- Of hA Ct VI
there is little or no water in the
sands the oil accumulates in the
syncline or lowest part of the oil
sand.
Mapping Underground Sand.
The possibility of accurately map
ping an underground sand without
the use of many well records was
determined only for the area investi
gated, for the accuracy of the results
of such work depends on the degree
of parallelism that exists between
the different geologic strata outcrop-
ping at the surface-that is, on the
regularity or irregularity of the re-
lations between the strata outcrop-
ping at the surface and the oil sands.
Before wells are drilled 1t is, OF
course. impossible to map sand, or
even to say that 1t exists; but If in
any area test wells drilled not over
to 5 miles apart have penetrated
the same sand, the high and low
spots of the sand and the slopes be-
tween these spots may be mapped
with an error not greater than 10 or
20 feet, If the outcropping strata ac-
curately indicate the structure.
The bulletin just published ex-
plains the methods of work and in
cludes detailed maps of the quad
rangles Investigated. Copies of it
may be obtained free of charge by
applying to the Director of the Uni
ted States Geological Survey at
Washington, ID. c.