, 1923-03-08

dence. Fields yielding NO oil pro-
duce gas In large volume. The
Monroe gas field Of Louisiana, the
largest gas field in the United States
has produced NO oil, although the
gasoline content Of the gas is 100
GALLONS to . million cubic feet. In
other fields gas is found in a reser-
voir separate from the oil. FIRE.
Quently. a. in parts Of the Midway
field. California, the gas occurs at
different stratigraphic depths over a
given area and efforts to correlate
these gas sands in we'll cross SEC
lions are fruitless. Again, a sand
may yield oil and gas in one part
Of q field and give gas only in an
another part. However. q a we'll
may lead to further prospecting and
the development OF producing oil
wells.
Marsh and Poisonous Gases
Marsh gas is not associated with
petroliferous deposits, but is found
most often in areas where masses
Of vegetation have been buried un-
der sediments, in streams, lakes, or
marshes, and have decayed with air
excluded. It burns as freely as nat
ural gas. Az marsh gas has no re-
lation to accumulations of oil, it
does not indicate the existence of
petroleum at equal or greater depth.
I Hydrogen sulphide gas is a color
less gas with characteristic odor very
poisonous. n part in 200 being fat
al to mammals. This gas is COM
monty If not universally, present
where oil is associated with salt
domes. The gas in the oil rock of
the Spindle Top field, Texas, is
poisonous. Enormous flows of this
gas have come from many salt-dome
wells. A flow of 5000, 600 cubic
feet daily came from Z wells in the
Bryan Heights dome, Texas.
Carbonic acid gas sometimes called
damp or choke damp, Is heavier than
air. 1t escapes from the ground in
many places. bubbles up in some
mineral springs and may show as
bubbles in the rotary ditch or the
bailed fluid. It will not burn nor
support combustion, and will put out
a candle flame in a confined space.
1t is in no way related to the oc-
curance of hydrocarbons.
Bubbles of air rising to the surface
OF q spring or pond are sometimes
thought to be natural gas. All ground
water contains air which may escape
as bubbles in consequence of higher
temperature or lower pressure.
Oil and Gas Indications
The so-called paraffin, or sour
dirt. OF the Gulf coast country is a
yellow. waxy substance resembling
paraffin or beeswax. It is p%opularly
deemed an unfailing indication Of
the proximity Of oil and gas reser-
voir. and is supposed to be the re-
suit OF natural gas emAnations.
The presence of amonia in Q fer
nation penetrated by the drill may,
In Q way. be an Indicator of the
presence OF oil or gas.
In q drilling well, petroleum may
be fund In any quantity. from q
whirling frridescent film on the water
In the ditch, to q sudden and per-
haps unexpected Eusher flow, but
all showings Of oil are not necessarily
signs Of oil. Grease from tool joints
can easily be mistaken fog a sigr Of
OIL. and holes in the greund nave
been "salted" with oil. Failure to
find oil is not conclusive proof OF
Its nonexistence unless the presum-
ably favorable reservoir has been
thoroughly tested.
Strata containing asphaltum or
tar are found in the higher levels
OF many fields during drilling and
may be a sign OF oil and gas at 4
greater depth.
The areal intimacy between known
coal deposits and oil and gas pools
In the United States. NAV be super
ficially explained ms a coincidence of
geologic segregation. Coal can occur
together with oil or gas. especially
the latter. only under certain limited
conditions in sedimentary rocks.
Nowhere can the development of
salt in a drilling well be considered
al an Indicator of the existence of
petroleum., except in the salines of
Louisiana and Texas. where salt
domes or plugs form the cores about
which oil has accumulated. Salt 10
an indicator OF a favorable structural