Petroleum and Natural Gas Fields in Wyoming Page: 35
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REVIEW OF OIL AND GAS FIELDS
SW1/4NW1/4 sec. 23, T. 29 N., R. 113 W.) 13
individual sands were proved gas productive
on formation tests. Most of these sands are
"stray" sands and are correlatable only over
a small area. The four main gas sands in the
fields have been named the K, La-Lz, M, and
Q and R. The K sand is thought to be the
base of the Knight formation. This sand
varies in thickness from 0 on the .western side
of the field to perhaps 80 feet on the eastern
side, accompanied by considerable variation
in thickness from north to south. Core anal-
yses show an average porosity of 27 percent,
permeability of 200 to 300 millidarcys, and
connate water 26 percent. Bottom-hole shut-in
pressures average 430 p.s.i. Back-pressure
tests show 5 to 23 million cubic feet open-flow
potentials for this sand.
The La-Lz sand interval averages approxi-
mately 380 to 400 feet below the K sand. It
varies in thickness from 0 at its western pinch-
out to 112 feet on the eastern side of the field.
Cores from the La sand show an average
porosity of 29 percent and 20 percent connate
water, with a permeability of 30 to 300 milli-
darcys. Bottom-hole shut-in pressures aver-
age 600 p.s.i. Back-pressure tests show stabi-
lized open flows of 1 to 40 million cubic feet
The M sand occurs about 75 feet below the
base of the La-Lz sand. It is characteristically
about 10 feet thick, although it does thicken
to 20 feet on the eastern side and to 40 or more
feet at the northeastern end of the field. A
few core analyses show an average porosity
of 21.9 percent, connate water content of 15.8
percent, and excellent permeability. Bottom-
hole shut-in pressure is approximately 610
p.s.i. This sand has tested gas at the rate of
915,000 cubic feet a day in one well.
The Q and R sands are dual sands, averaging
some 20 to 30 feet apart and coming in around
700 feet below the M sand. These sands are
widespread over the field, having been found
productive in two wells 10 miles apart. The
Q and R sands pinch out to the west and at-
tain a maximum thickness of 40 feet on the
east side of the field. Core analysis from one
well shows the average porosity to be 16.2 per-
cent, with connate water of 41.2 percent. Bot-
tom-hole shut-in pressures from three wells
average 1,210 p.s.i.
Two small oil wells were completed by Sep-
tember 1955 in secs. 34 and 35, T. 30 N., R. 113
W., with initial capacities of 40 and 24 barrels
daily, respectively. The oil came from sands
in the Wasatch formation.
Analysis of gas from the K sand (Wasatch),
La sand (Wasatch), and K Almy sands and
water from the Wasatch are given in tables
8 and 9 (pp. 287 and 293, respectively).
In November 1957, 44 wells in the field were
reported producing at the rate of 1.9 million
cubic feet of gas per well daily.
In September 1955 construction of a 50-mile,
16-inch-diameter pipeline to Opal, Wyo., was
completed. It connects with the main gas pipe-
line of the ,Pacific Northwest Pipe Line Com-
pany near Opal.
No oil production was reported from the
field before the end of 1956.
The Big Polecat anticline (fig. 20) extends
through the center of T. 57 N., R. 98 W., Park
County. It has two highs, which are on the
same line of folding as the Garland anticline
and about 10 miles northwest of it. These
highs are referred to as Danker and McMahon
domes or, together, as -the Big Polecat anti-
cline. Danker dome is in secs. 16 and 21, and
McMahon dome is in sec. 27. Upper beds of
Cody shale outcrop on Danker dome, and
Mesaverde sandstone hogbacks flank the dome.
The surface elevation of the wells in sec. 16
averages 4,540 feet. Each dome has an inde-
pendent closure of about 100 feet. Contours
of the top of the First Frontier sand indicate
faulting to be present on both domes.
Gas was discovered on McMahon dome in
1916, when a well was drilled in the SE1/4
NW1/4 sec. 27 that produced an open-flow
volume of 21/ million cubic feet of gas daily
from the Frontier formation at 2,232 to 2,272
feet. Seven additional wells were drilled on
the anticline to the Frontier sands by June
1954; of these, five yielded gas at rates rang-
ing from 1/2 to 7 million cubic feet daily;
shut-in wellhead pressures were 600 p.s.i. Oil
was discovered in August 1954 when a well
drilled in the E1/2SE1/4SWl/4 sec. 16 was
completed with an initial daily production, by
pumping, of 374 barrels. The producing zone
was the Tensleep formation from 5,362 to
5,512 feet. The log of the Tensleep discovery
well shows the depth, in feet, to the top of
formations as follows: Cody, 830; Frontier,
2,260; Torchlight sand, 2,432; "A" sand, 2,512;
Peay sand, 2,710; Mowry, 2,820; Muddy sand,
3,490; Cloverly, 3,590; Dakota, 3,700; Fuson,
3,828; Lakota, 3,990; Morrison, 4,085; Sun-
dance, 4,298; Gypsum Spring, 4,640; Chug-
water, 4,820; Dinwoody, 5,290; Phosphoria,
5,320; Tensleep, 5,358; and Amsden, 5,555.
To the end of 1957, seven oil wells and five dry
holes had been completed on the dome.
In December 1956 the seven oil wells aver-
aged 800 barrels of oil and 800 barrels of
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Biggs, Paul & Espach, Ralph H. Petroleum and Natural Gas Fields in Wyoming, report, 1960; Washington D.C.. (digital.library.unt.edu/ark:/67531/metadc38797/m1/49/: accessed April 27, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.