Montana oil and mining journal. [volume] (Great Falls, Mont.) 1931-1953, 1939-05-13

Coupled with improved drilling meth
DDS are improved production methods
too numerous to mention. In this again
comes the magic. The operator used to
fear drilling with rotary tools because
column of heavy mud Is forced hack
into the formation, shutting off oil and
gas production which could not hereto
fore be recovered. Today he drills calmly
through the upper sands and continues
on to his objective. Thereafter he rims
magic device into the hole that rec
Ords every sand, through the sheath of
mud. 1t also shows pOrosity and even re-
VeaIs SATURA1ION. After such a survey
the operator may run casing in the hole
content with the knowledge that he can
go in at some future time with a ''gun
perforatOr" and shoot holes through the
casing and into the formation and bring
into production horizons that had been
mudded off during drilling. Thus he can
reclaim over a period of years all of the
lesser producing strata in the hole.
Add to this the use of acid familiar
to all MOntanans, I'm increasing the pro-
duction of lime wells. The day is at hand
when acid will be used in sand wells.
The new acid will penetrate and dissolve
hard sandstone and open up flow chan
nels through which oil can penetrate i'm
to the drill hole. Thus a six-inch hole
drilled through a sandstone may be en-
oil can drain from the formation.
How much the chemists have added to
the oil reserves of this country none
can guess but it is certain that acid has
doubled the recoverable oil in many lime
fields. Improved drilling methods, inn
proved methods of utilizing natural pres
sure to flow the production and other
contributions of science are daily increas-
ing the yield per well. In other words,
every dollar invested in drilling today
can be made to give greater returns than
ever before.
The business of finding new oil fields
has i'm the past been the most hazar-
dOus part OF the oil industry. In the Mid
continent, where surface exposures made
it difficult for the geOlOgist to find an
ticlines, il was the custom to drill wells
at random, at given intervals across a
vast open country. Whenever a showing
of oil was found, the drilIers cOncen-
trated around that well working out in
all directions until a pool was found.
Thirty and forty wells were sometimes
drilled in the effort to find pool. That
was expensive business. The "wildcatter''.
as the oil prospectOr was called, was tru-
ly engaged in a most hazardous enter
prise.
Today magic" has been introduced
in the finding of oil sands OF first inn
pOrtance is the science of geOphysics by
which ii is possible to penetrate the man
tie of gravel or other covering over the
bedrock of the earth's surface, and meas
ure accurately the degrees of dip of all
formations above the granite. The cost
of a geophysicaI survey is usually less
than the cost of one of the 80 or 40
wells of the Olden days. GeOphysics have
been developed to a point where there
is no great degree of inaccuracy.
Now that the structure, trap for oil,
can be definitely established without
drilling, the next step is to determine
whether 1t contains oil. Again science
has stepped forward and has introduced
''soil analysis. One writer has defined
soil analysis as the location Of oil re-
serves by application of the microscopic
method to the finding of oil and gas
seeps."
In the early days of the oil business
he operator would drill close to an oil
'eep. This method was not satisfactory,
although seep was positive proof of
he existence of oil in the district. The