The Barre daily times. (Barre, Vt.) 1897-1959, 1917-04-28
OIL-DRILLING.
Some Facts of Interest About the 0per
alton.

ALUM.
/ Work in the California oil fields by tn,
United States geological survey OF thu
department Of the interior has devel
oped some interesting facts which viii
doubtless be of considerable benefit Il
the oil industry. 1t has long been rec
ognized that oil and gas are commonly
associated with water, but of the chem
ical relation between the two little has
been known. 1t is now possible, al
least in California, according to the sur.
yey, to estimate the position OF oil and
gas, where present, from chemical
analysis Of the water encountered by
the drill. Thus in drilling wild cat
well an indication of the presence or
absence OF oil and gas below the water
may be had by analysing the waters
successfully encountered, since investi-
cations have determined that the deep
seated waters associated with oil in
California fields are different in chemical
composition from the waters found near
the surface as well as from the deeper
waters outside of the oil fields. In some
areas a significant change in composition
may be detected as much as 1000 feet
above the oil. In others the upper lin
it of alteration may be within few
hundred feet of the oil.
| 1t is possible to determine, at least
in a general way, the source of the wat
er flooding an oil well. In the Westside
Coalinga Geld, for example, the horizon
OF the water may thus be determined
rather definitely; in the Midway-Sun-
set field, where the distinctions are less
sharp, the success of this method will
depend largely on the number of authen-
tic analyses that are available for COM
parison.
In the old fields of the San Joaquin
valley water bearing sands are generally
encountered above, below, and in many
places in the oil measures, and in these
fields it is difficult to prevent the water,
which may be under high pressure, from
invading the oil sands and thus running
considerable tract of oil land The
United States geological survey accord
ingly detailed g. Sherburne Rogers to
make study of water conditions in
these fields, with special reference to
the chemical character of the waters. !
Some of Mr.. Rogers conclusions, drawn
from study of several hundred ana
lyses of water from different depths, are |
as follows:
!. Although some OF the old-feld wat |
ers are as salty as sea water, and are |
probably true fossil sea water, others /
are not even slightly salty to the taste.
The distribution of salt is controlled |
by the freedom of circulation of the
waters, which is governed chiefly by /
the geologic structure.
g Although the surface and shallow
ground waters are strong sulphate or i
amount as the oil measures are APP Il
preached and finally disappears. Outside
the oil fields, however, large quantities
Of sulphate are found in even the deep
est waters.
g. The waters a short distance above
the oil at many localities are sulphur
containing the gas hydrogen
but the shallow waters and
those in the oil measures generally con-
tain no sulphide.
a. Carbonates, which are subordinate
n the shallow waters, increase in amount
rs the oil zone is approached, and il no
'hlorides are present constitute the only
dissolved salts in the waters associat- ,
"a with the oil. !.
These conclusions appear to be well !
rounded for California, and probably
lold for other arid regions in which the
upper waters are sulphate or "alkali."
Chemical Action of Water on Oil. :
The progressive alteration of the wat +
r as oil is approached is SO constant
nd so striking in the area examined
hat the conclusion that the oil and wat
r have reacted chemically can not be
yoided. 1t was suggested long ago in
he Russian oil fields that hydrocarbons
re able to reduce sulphste to suphide,
nd that they themselves are stimuli
aneously oxidized to carbon dioxide or
arbonate. The reaction has not yet
cen checked in the laboratory, however,
nd though essentially correct is prob
bly, much more complicated than has
cen supposed
Some of the sulphide formed in the
faction between the hydrocarbons and
ne sulphate waters is undoubtedly oxi-
lied to sulphur Some of this sulphur
taken up again by the oil, which
axes the oil heavier and more asphalt
In the oil fields OF San joaquin val
v the oil that has been most exposed
the action of the water generally con-
inns the most sulphur and is of the
CHEST gravity. 1t seems probable that
lie natural gas is also affected by these
actions, and that some of the carbon
oxide formed is not taken up by the
aters but mixes with the gas and thus
wers its heating value. The gas neer-
t the outerop of the oil sands where
lphate water can most readily enter
e strata and where the reaction would
ost naturally be most vigorous, may
ntsin as much as 35 per cent of car
n dioxde.
A preliminary report on California