Upload
others
View
0
Download
0
Embed Size (px)
Citation preview
Figure 1. Generalized stratigraphy of the Dakota Group. There are no reliable data sets for North Dakota that either list, or enable determination by extrapolation, subsurface temperatures for Cretaceous rocks. Bottom hole temperatures from oil well logs are unreliable and to assume that a simple linear relationship exists between temperature and depth would be incorrect. Although grossly linear the geothermal gradient in the upper lithosphere is significantly affected by thermal variables (heat flow and thermal conductivity) in the earth’s crust. Any method used to accurately calculate subsurface temperatures must therefore take these factors into account. Provided the subsurface stratigraphy is known, Gosnold (1984) showed that at a given depth (Z) the temperature (T) can be represented by the following equation: T = To +
n
i 1Zi(Q/Ki)
Where: To = Surface temperature (in °C) Zi = Thickness of the overlying rock layer (in meters) Ki = Thermal conductivity of the overlying rock layer N = Number of overlying rock layers Q = Regional heat flow For the data set used to produce this map T0, K and Q were assumed to be constants. Mean surface temperature (T0 = 5.1° C [41° F]) was calculated from monthly station normals (at Bismarck Municipal Airport, Fargo Hector Airport, Grand Forks International Airport, and Williston Sloulin Airport) for the period 1971 to 2000 (http://cdo.ncdc.noaa.gov/climatenormals/clim81/NDnorm.pdf). Thermal conductivities (K) for formations overlying the Mowry are shown in Table 1. Formation Thermal Conductivity (W/m K) Late Cretaceous, Paleogene and Neogene clays, silts and sands 1.7 Pierre 1.2 Greenhorn 1.2 Table 1: Thermal conductivity estimates from Gosnold (1984) Regional heat flow (Q = 62 mW/m2) was averaged from statewide data. Rock units and thicknesses were obtained from oil well log tops (July 2006 update). Temperatures were only calculated for wells where all relevant log tops were given since omissions (particularly for the Pierre Formation) do not necessarily imply that units are absent. Metadata used in the compilation of this map is available on CD.
"
"
"
"
"
"
"
"
"
"
!
! !
!
!
!
!
!
!
!!
!!
!
!
!
!
!
!
!
!
!
!
!!
!
!
!
! !
!
!
!
!
!!!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
168
168
170
171
Banks
1806
1804
1804
(/85
(/2(/2
1804
Tren ton
(/2
(/2
(/85
(/2
(/85
WILLIAMS C OUNTY
MCKENZIE COUNTY
WILL IAMS COUNT
Y
MC KENZIE
COUNTY
WILL
I AMS C
OUNTY
MCK E
NZIE
CO
UNTY
MISS
OURI
RIVE
R
White Tail Bay
To bacc
o Gar
d en B
ay
T o b a c c o
G a r
d e n
C r e e
k
S a n dC r e e k
S i x m i l e
C r e e k
C r e e k
E i g h t m i l e
P a i n t e d
C r e e k
W o o d s
C r e e k
S a n d
L i t t l e
M u d d y
R i v e r
TwinLakes
B l a c k t a i l
C r e ek
Blackta ilLake
O t t e r
T r a i l
C r e e kC o w C r e e k
C o w
C r e e k
W i l l o w C r e e k
L i t t
l e
M u d d
yR i
v e r
Lone TreeLake
E a s tF o r k
E a s t
F o r k
L i t t l e
M u d d y
R i v
e r
McLeodLake
S t o n yC r e e k
E p p i n gD a m
S t o
n y
C r e e
k
W i l l o
w
C r e e k
L o n eC r e e k
C r e e k
G a m a c h e
TobaccoGar den
Creek
N e l s o n
C r e e k
B e a v e rC r e e k
B e a v e rC r e e k
L A K E S A K A K A W E A
L A K E S A K A K A W E A
5000
5000 5000
4750
4750
5000
4500Ray
Avoca
Epping
TempleMarmon
Marley
Wheelock
Williston
Bonetrail l
Lake Jessie
Spring Brook
WestBonetrail l
11 111 11 616 6
1
6 6
11
6
1
6
1
6
61 11666 66 6
1
1
1
6
11 1 16 1
1
1 6
1
1
6
1 1
1
1
1 1
6
1
1
6
1
1 61
6
66 6
1
1 1
6
6
66 1
1
6
61
6
1616
6
16
66
6
6
6
6 6
6
6
6
6
6
36
3636
31
36
31
36
36
36
31
36
3636 31
31
36
31
36
36
36
31
36
36
3636
31 31
36
31
36
36
3636
36
31 31
36
31
36
36 36
36
3636 31
31
31
31
31
3136
31
31
36
36
363136
31 3136
36 31
36
3631
31
31
36
31
31 3636
31
36
31 31
31
31
36
36
36
31
31
31
3131
36
31
31
31
3131
31
6
31
31
31
31
104o 00 '48o 30 '
103o 00 '
48o 30 '
104o 00 '48o 00 '
103o 00 '48o 00 '
North Dakota Geological Survey100K Series: Wlst - g - Km Deep Geothermal Resources: Estimated Temperatures on Top of the Mowry Formation
R. 103 W.
T. 15
7 N.
T. 15
5 N.
T. 15
3 N.
T. 15
2 N.
T. 15
4 N.
R. 101 W. R. 100 W. R. 99 W. R. 98 W. R. 96 W.R. 97 W.
R. 104 W. R. 102 W.R. 103 W. R. 101 W. R. 100 W. R. 99 W. R. 98 W. R. 97 W.
T. 15
6 N.
Carto graphic Compilation : Elroy L. Kadrmas
R. 95 W.R. 102 W.
Edward C. Murphy, State GeologistLynn D. Helms, Director Dept. of Mineral Resources
T. 15
8 N.
R. 96 W.
Williston 100K Sheet, North Dakota 1983 Magne tic NorthDeclinati on at Center of S hee t
13o 30'
Lorraine A. Manz2007
Note: This map was expanded beyond the normal Williston 100k Sheet to include anadditional width of two miles to the Montana border.
Mercato r Projection 1927 N orth American Datum
Shaded Relief - Vertical Ex ag geration 9 xStand ard parallel 48 o 00' Central meridian 1 03o 30'
0 1 2 3 4
Miles
Scale 1:100,000
Williston 100K Sheet, North Dakota Adjoining 100K Maps
Age (
MYr
)Pe
riod
100
140
Rock Column Rock Unit Descr iption
Mowry
Newcastle
Skull Creek
Inyan Kara
CRET
ACEO
US
Sandstone, l ight-gray, f ine- to me dium-gra ine d, silty; sha le,medium- to da rk-gra y, soft, lumpy, fissile, micac eous.
Sha le, me dium- to da rk- gray, soft, mic aceous, lumpyto ma ssive, spongy; includes beds of bentonitic cla y.
Sha le, me dium- to da rk- gray, micace ous, soft flaky tolumpy; sa ndstone , fine-grained, fr iable, c alcareous,light-gray, glauconiti c; trace s of pyrite and whitebentonitic cla y.
Upper pa rt: marine sa ndstone , light-gra y, fi ne to coarse,quartzose ; shale, gra y, silty, lumpy. Lower part: nonma rine sa ndstone , me dium to coarse ,quartzose ; occa si onal lense s of gray, be ntonitic shalecommonly contains Mn-FeCo3 spherulit es.
144145146147148149
150151152153154155156
157158159160161162163
164
170Temperature/oF
143165166167168169
Geologic Symbols
!
Depth (in feet from surface)To Top of Mowry Formation
Data Points. Selected points show temperature in oF
168
References Gosnold,W.D. Jr., 1984, Geothermal Resource Assessment for North Dakota. Final Report: U.S Department of Energy Bulletin No. 84-04-MMRRI-04.
Geothermal energy is a renewable resource capable of producing an uninterrupted supply of electrical power and heat. In stable sedimentary basins, low-temperature geothermal energy (< 100° F) is extracted from the shallow subsurface (~8-400 feet) for use in domestic and commercial heating and cooling systems. Historically, deeper, hotter resources in these regions have not been developed because they were not economical. However, as the nation explores ways to reduce its dependency on foreign energy sources and also begins to look more closely at renewable energy, accessing deep geothermal energy resources, particularly via existing oil and gas wells, is attracting a great deal of interest The Dakota Group contains the shallowest of four major geothermal aquifers that occur in the Williston Basin. The map shows calculated temperatures (°F) for the top of the Mowry Formation, the uppermost of the four rock units that comprise the Dakota Group (fig. 1).
( http://www.smu.edu/geothermal/).
http://cdo.ncdc.noaa.gov/climatenormals/clim81/NDnorm.pdf
Other FeaturesWater
County Boundary
Unpaved Road
Stream - Inte rmittent
Paved Road
River/Stream - Perennial
Sta te Highway(/85 Federal Highway
1806