Montana oil and mining journal. [volume] (Great Falls, Mont.) 1931-1953, 1932-11-26

way divided North America into
two parts in a nOrth-sOuth direc-
tion.
The Colorado shaIe seems 20 be
Of first importance a. possible
source Of Oh and gas in north
western Montana and according to
present information Is the only
promising source known. In the
area here discussed the lower part
Of this shale was found to be
peroliferous IN every extensive
exposure On . belt extending about
IS miles fiom north % souah
across the area between Deep Greek
and san River. IL contains BIT
luminous shale which yields OH
on distillation. and soft ualtha
or natural tar n Crevtces Of frac-
tured limestone, which very prob
ably is . residum from the evaR-
Oratlon Of petroleum. The eyt-
dence seems fairly conclusive that
this shaIe offers . source for
petroleum that may have accumu-
lated in commercially valuable
quantities either in the Colorado
or IN the sandy portions Of the
Kootenai and VtrgelIe sandstone IN
immediate contact with #.
Further evidence as to the im-
portance Of the Colorado shaIe IS
q possible source Of oil and gas in
northwestern Montana seems 70 Be
offered by experience IN the sd
Joining regions 20 the north and
south. In Wyoming the principal
production In the salt Greek field
and in all the fields IN the Big
Horn Basin Is derived frOn sand
stones in or IN contact with this
formation. In souehern Alberta the
large quantity Of gas prOduoed IN
the Bow Island gas field, which Is
distributed By pipe line as far as
Calgary. comes fron . sandstone
associated with the Colorado shAIe
On the Turner Valley anticiine, in
the sheep River area southwest Of
Calgary, and on other closely COM
pressed folds IN that vicinity small
yields, as mach as barrels
dag, Of very high grade iight-green
70 coI0riess oil. in addition 10 large
amounts OF saturated gas, were OBJ
tanned from sand beds associated
with the formation. (Reamenber
that this was written IA years ago
and before Turner Valley was
drilled in). At first thought the
small amount OF oil found does
not seem very encouraging, but IL
should be noted that the folds
that have proved productive are
long and narrow, with high dips, are
much faulted, and therefore prob
ably have very small collecting areas
down the dip. The productive anti-
cIines in Wyoming have collecting
areas that are 9 20 10 miles or
more wide down the dip, and Il
Is therefore possible that these
small yields Ga the Sheep River
field from very much smaller coli
Iecting areas Indicate an original
oil saturatiOn In the Colorado shaIe
AS GREAT AS THAT In THE
WYOMING FIELDS. the problem
In this general region being 20 find
structural features that have coli
Letting areas comparable in size
with those in Wyoming.
Mr. stebinger. describes the Black
leaf sandstones as 90 to rs feet
thick. There are no such sand
thicknesses In the sweetgrass Arch,
where hundreds Of wells have been
drilled. II follows that the shore
line condition extends along the west
edge OF the sweetgrass Arch:
condition which steblngeF could
not possibly foresee, since there
was not enough web data to re-
veal This shore line as conclusiYeiy
as we now know H. II is interest
ing 70 us to note that Mr.. Stebdnger
recognized the SIGNIFICANCE Of
that e-barrel well on Sheep Greek.
That significant fact led to the de-
velopment Of the great Turner
Valley field.
Now that these sands which steb-
niger said would produce ARE
producing ct Cut Bank and this
tremendous body Of oil bearing
sand Is q known fact. does it not