AAPG-RMS 2011 - Cheyenne, WY
During deposition of the upper Green River Formation in the late Eocene, Utah’s Lake Uinta transitioned from a balanced-filled basin dominated by organic-rich, lami-nated marlstone, to an underfilled restricted basin. During this time, the saline mineral nahcolite formed within the deep-lake sediments (depocenter in central Uintah County) as isolated crystals, nodules ranging up to one foot in diameter, and beds ranging from less than an inch to 2 feet thick. Post-deposition, the saline mineral short-ite was deposited in fracture zones several feet thick. More recently, the Birds Nest aquifer formed from the dissolution of these saline minerals and is targeted by natural gas producers as a potential saline water disposal zone. Recently completed core descriptions, measured sections, and five newly constructed stratigraphic cross sections show that the total thickness of the Saline zone ranges from <100 feet on the basin’s eastern and southern margins to >300 feet in the basin’s depocenter. Only in the basin’s depocenter, where the Birds Nest aquifer comprises two stratigraphic zones of dissolution each between ~40 and ~100 feet thick, is there potential for extensive saline water disposal. Ongoing research and monitoring pro-grams seek to determine if these individual zones are hydraulically connected or if the Birds Nest as a whole is vertically connected via fractures/joints (possibly gilsonite veins) to other water-bearing zones both above and below. Regional water sampling shows that the Birds Nest’s water chemistry in the north (averaging >10,000 mg/L TDS and as high as 100,000 mg/L TDS) is distinct from that in the south (averaging <10,000 mg/L TDS and as low as about 1000 mg/L TDS). This abrupt change in water chemistry is most likely due to the differing amounts of saline mineral dissolution in the two areas; the southern area may have been flushed clean, whereas saline minerals in the northern area are still actively dissolving. The presence of intact nahcolite in the Utah State 1 core (section 26, T. 9 S., R. 21 E.) – on display with this poster – demonstrates that there are still zones of no dissolu-tion north of the 10,000 mg/L TDS line. Just to the south of this well, the saline minerals in the Birds Nest show significant dissolution, as seen in the Utah State 13X-2 core (section 2, T. 10 S., R. 21 E.) – also on display. Separating these two areas is a prominent gilsonite vein that cross-cuts the Birds Nest aquifer. The northwest-trending gilsonite veins in the area seem to influence groundwater flow patterns in the Birds Nest by creating “channels” of dissolution and impermeable barriers to flow. The Birds Nest aquifer’s spatial and stratigraphic extent and variability, water chemistry, and zones of differential dissolution will determine possible saline water dis-posal volumes and safe disposal practices, both of which could directly affect the success of increased petroleum production and potential oil shale development in the region.
Natural gas, crude oil, and water production in the Uinta Basin, Utah, 2002-2010
Source: Utah Division of Oil, Gas, and Mining
8-year increase in natural gas production - 169%8-year increase in crude oil production - 139%
8-year increase in water production - 72%
100
150
200
250
300
350
2002 2003 2004 2005 2006 2007 2008 2009 2010
Nat
ural
gas
pro
duct
ion
(bill
ion
cubi
c fe
et)
0
20
40
60
80
100
Natural Gas ProductionOil ProductionWater Production
Cru
de o
il an
d w
ater
pro
duct
ion
(mill
ion
barr
els)
More than 25,000 oil and gas wells are currently proposed for drilling in the Uinta Basin
This future drilling will greatly increase the amount of produced water needing proper disposal
• West Tavaputs Natural Gas Full Field Development Project - 626 new wells - approved• Uinta Basin Natural Gas Development Project (Gasco) - 1491 new wells - proposed, draft EIS• Greater Natural Buttes Area Gas Development Project - 3675 new wells - proposed, draft EIS• South Unit Oil and Gas Development Project - 400 new wells - proposed, draft EIS• Greater Chapita Wells Natural Gas Infill Project - 7028 new wells - proposed, EIS in process• Greater Monument Butte Project - 5570 new wells - proposed, EIS in process• Bureau of Indian Affairs - 4899 new wells - proposed, EIS in process• River Bend Field Development Project - 484 new wells - proposed, EA in process• Big Pack Natural Gas Development Project - 664 new wells - proposed, EA in process• Southam Canyon Field Development Project - 249 new wells - proposed, EA in process
Source: U.S. Bureau of Land Management
0 9 18 27Miles
Duchesne River
Gree
n Ri
ver
White River
DUCHESNE
UINTAH
WASATCH
UTAH
CARBON
GRAND
EMERY
West Tavaputs Natural Gas Full Field Developoment Project - 626 wells
Uinta Basin Natual Gas Development Project (Gasco) - 1491 wells
South Unit Project - 400 wells
Greater Monument Butte Project - 5570 wells
Bureau of Indian Affairs - Oil and Gas Development on the Uintah and Ouray Reservation - 4899 wells
Greater Natural Buttes Area Gas Development Project - 3675 wells
Southam Canyon Field Develop-ment Project - 249 wells
Big Pack Natural Gas Develop-ment Project- 664 wells
Greater Chapita Wells Natural Gas Infill Project - 7028 wells
River Bend Field Develop-ment Project - 484 wells
Area currently leased for oil and gas development
The Birds Nest aquifer is poorly understood and needs further study to determine potential impacts of using this aqui-fer as a saline water disposal zone.
• What is the aquifer’s areal and stratigraphic extent?
• How is this aquifer related to Utah’s oil shale deposits?
• What causes the aquifer’s differing zones of dissolution and salinity?
Eastern Uinta Basin natural gas producers have identified the Birds Nest aquifer, located in the Parachute Creek Member of the Green River Formation, as the most promising reservoir suitable for large-volume saline water dis-posal. This aquifer formed from the dissolution of saline minerals which left behind large open cavities and fractured rock. Understanding the aquifer’s areal extent, thickness, water chemistry, and zones of differential dissolution will help determine possible saline water disposal volumes and safe disposal practices, both of which could directly impact the success of increased hydrocarbon production in the region. The Birds Nest aquifer is typically several hundred feet above the richest oil shale interval called the Mahogany zone. A significant concern is that saline water disposal into the Birds Nest by conventional gas producers could hinder oil shale development by creating unforeseen water disposal problems.
Origin of the Birds Nest aquifer name, mud swallow nests in nahcolite cavities.
25E24E23E
0 4 82Miles
EX-1
13X-2
14-36
14X-34
42-34
Red Wash 1
Coyote Wash 1
Asphalt Wash 1
Corehole 10 CRU-1
SUB 12
Suicide Canyon 1
P-3DP
X-13P-2 P-4
Corehole 2
P-1
Utah State 1
White River
Skyline 16
Corehole 9
Anadarko BNdisposal wells
EOG BNdisposal wells
Questar BNdisposal wells
22E21E20E
9S
10S
11S
12S
Colorado
8S
7S
6S
Duchesne River
Green River
Explanation
Cross-section well
BN disposal well (red = proposed)
Horsebench/Saline zone outcropGilsonite vein
River
County boundary
Township and range
Birds Nest Aquifer - Upper and lower zone
Birds Nest Aquifer - Lower zone and partial upper zone
Birds Nest Aquifer - Lower zone only
UGS core - partial Birds Nest zoneUGS core - complete Birds Nest zone
USGS core - partial Birds Nest zoneUSGS core - complete Birds Nest zone
Mahogany zone outcrop
Well used to define BN zoneMeasured section (*not yet completed)
Major road
6SMaximum areal extent for possible saline Maximum areal extent for possible saline water disposal into the Bird Nest aquiferwater disposal into the Bird Nest aquifer - Areal extent of large saline nodules/beds - in one or two zones - Chemistry of water currently in aquifer will be a limiting factor - Some areas may be lacking suffient dissolution of the saline minerals, further limiting extent suitable for dispsoal
BitterCreekSection
Long DrawSection
WatsonSection
EvacuationCreek
Section*
UINTAH CO.DUCHESNE CO.
Darkest blue shadingUpper and lower BN aquiferLarge saline nodules/bedsAs seen in the 13X-2 core (right)
Lightest blue shadingOnly lower BN aquiferLarge saline nodules/bedsAs seen in the P-4 core (right)
No shadingSmall saline mineral crystals in BN aquiferAs seen in the SUB 12 core (right)
BuckCanyonSection*
This map records where large saline mineral nodules/beds are present based on geophysical logs and core descriptions; the dissolution of such nodules creates the space for potential large-scale water disposal.
Lower Birds Nest Aquifer IsopachLower Birds Nest Aquifer Isopach
0 4 82Miles
20-40 ft
40-60 ft
60-80 ft
Thickness of Birds Nest
80-100 ft
100-120 ft
This map records where large saline mineral nodules/beds are present based on geophysical logs and core descriptions; the dissolution of such nodules creates the space for potential large-scale water disposal.
Upper Birds Nest Aquifer IsopachUpper Birds Nest Aquifer Isopach
0 4 82Miles
20-40 ft
40-60 ft
60-80 ft
Thickness of Birds Nest
80-100 ft
100-120 ft
120-140 ft
ABSTRACTABSTRACT
PROBLEMPROBLEM
• Conduct comprehensive literature review and historic data collection (finished, but not presented on this poster)
• Evaluate the Birds Nest aquifer in core: - 22 wells have been identified as having all or part of the Birds Nest captured in core; 21 of the 22 cores have been examined (The DP core was not examined becasue of its close proximity to the examined X-13 core) (see below)
• Evaluate the Birds Nest aquifer on outcrop: - Good outcrop exposures can be found on the southeastern side of the basin (3 measured sections have been completed (see map below), but are not presented on this poster)
• Evaluate the Birds Nest aquifer on geophysical logs (~330 wells examined, 5 regional cross sections completed, see map below)
• Determine how disposal into the Birds Nest aquifer could affect future oil shale development (ongoing)
• Determine how gilsonite veins might influence water flow and saline mineral dissolution (see panel 2)
• Create a GIS database and maps showing: - Outcrop (see map below)
- Thickness (see maps below and right)
- Lateral extent (see map below)
- Water quality (see panel 2)
- Interburden between Birds Nest and “economic” oil shale zones (see panel 2)
RESEARCH / DELIVERABLESRESEARCH / DELIVERABLES RESULTS: SPATIAL EXTENT AND THICKNESSRESULTS: SPATIAL EXTENT AND THICKNESSResearch methods: Core, outcrop, and geophysical log examinations
The Saline zone is nearly 400 feet thick in the basin’s paleo-depocenter. Within the Saline zone, the Birds Nest aquifer is separated into an upper and lower zone where dissolution of the saline minerals has created significant porosity and permeability for the transmission of water (see 13X-2 core log). The large saline mineral nodules and beds in the paleo-depocenter are recorded as spikes to low density on geophysical logs. To the east, the upper zone disappears and only the lower zone exists (as seen in the P-4 core). Radiating out from the depocenter, the Saline zone thins to ~130 feet and contains much smaller saline mineral crystals (<1 inch) as compared to the large (up to 1 foot) nodules found near the basin’s center, and the bulk density signature is lost (there is still a zone of dissolution in the lower por-tion of the Saline zone which could transport water and is roughly equivalent to the lower Birds Nest zone found in the basin’s center). This transition is confirmed to the south where cores and outcrop ex-posures are present (see SUB 12 core log). It is presumed that the same transi-tion to small saline crystals exists to the north and west, but no cores exist to con-firm this suspicion.
• Highlight: Using geophysical logs, UGS has mapped the spatial extent and thickness of the Birds Nest aquifer where large nodules exist in both an upper and/or lower zone. This represents the maximum area with potential for saline water disposal, but only where water currently within the zone is greater than 10,000 mg/L TDS and where saline mineral dissolution has already taken place.
Photo 11532 ftShortite dissolution
Photo 21774 ftDissolved nahcolite nodule lined with pyrite
Operator: Tosco Corp.Location: T10S, R21E, Sec. 2, UTM E 625912, UTM N 4425960Cored interval: 120 - 2191 ft, 3.5 inch diameter (only examined 1289-1818 ft)Core location: UGS and USGS Core Research Center
m c
Utah State 13X-2 exhibits extensive saline mineral dissolution (see dissolution log) in two distinct zones, the upper aquifer is 56 feet thick (1516-1572 ft) and the lower aqui-fer is 101 feet thick (1690-1791 ft). This well is very near Anadarko’s saline water disposal wells.
13X-213X-2 - Upper and lower Birds Nest aquifer
clay silt
Upper R-62263 ft
Big Three1872-1890 ft
Stillwater1912-1923 ft
Four Senators1942-1970 ft
R-81352 ft
Uinta Form
ation
Green R
iver Formation - Parachute C
reek Mem
ber
Lithologic Units
-300 300SP
Depth (ft)
1.7 2.7Bulk Density (g/cc)
6 10Caliper (in)
Core Logsand
Middle R-62361 ft
A-Groove2078 ftMahoganyZone2091 ft
B-Groove2181 ft
MahoganyBed 2126 ft
fvf
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
0 300Gamma Ray (api)
SP shift
SP shift
SP shift
Saline MineralDissolution IndexNone Total
Saline Zone 1408-1797 ft
SP shift
0.1 10000Resistivity - Laterolog-8 (ohms)
1200
1300
1400
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1600
1700
1800
1900
2000
2100
Depth (ft)
2200
2300
2400
Lower BirdsNest aquifer1690-1791 ft
Top of economicoil shale - 1872 ft
Photo 1
Photo 2
Bed 761625 ft
Uinta Fm.
Upper BirdsNest aquifer1516-1572 ft
Birds Nest aquifer in outcrop along Evacuation Creek, eastern Uinta Basin. The large cavities resulted from the dissolution of nahcolite nodules, creating the aquifer’s porosity and permeability.
Birds Nest outcrop atWhite River water level- Recharge area
Evacuation CreekCanyon
White River
Horsebench Sandstone
Birds Nest aquifer
Photo 4365 ftShortite dissolution
Photo 2 354 ft Dissolved nahcolite nodule
Only the lower Birds Nest aquifer is present on the eastern side of the basin, as shown by core from the P-4 well. The aquifer is defined by very large nahcolite nodules (up to 1-foot in diameter, seen better in outcrop near the well) and almost total saline mineral dissolution. Significant, porous sand beds (Horsebench) overlay the Saline zone and could be part of the aquifer system. The sand deposition might represent fresh water entering the lake which changed the local water chemistry, stopping the saline mineral deposition.
Operator: White River Shale ProjectLocation: T10S, R25E, Sec. 19, UTM E 659426, UTM N 4421812Cored interval: 214 - 1173 ft, 3.5 inch diameterCore location: Utah Core Research Center
P-4 P-4 - Lower Birds Nest aquifer only
Photo 3362 ftDissolved nahcolite nodule and warped bedding
Dissolvednahcolitenodule
clay siltvf
A-Groove673 ftMahoganyZone682 ft
B-Groove785 ft
Upper R-6822 ft
Big Three487-504 ft
Stillwater527-536 ft
Four Senators561-592 ft
Wavy Tuff635-638 ft
MahoganyBed 719 ft
Saline Zone 290-411 ft
R-8?? ft
Uinta Form
ation
Green R
iver Formation - Parachute C
reek Mem
berLithologic Units
0 250Gamma Ray (api)
0 1000Resistivity (ohms)
0
100
200
300
400
500
600
700
800
900
Depth (ft)
1.7 2.7Bulk Density (g/cc)
6 10Caliper
Curly Tuff779-782 ft
0
100
200
300
400
500
600
700
800
900
Depth (ft)
Core Log
f m csand
Lower BirdsNest aquifer
334-411 ft
Photo 2Photo 3Photo 4
Top of economicoil shale - 487 ft
Horsebench Ss.
Si-dominatedmudstoneSiltstone /vf sandstone
Abundant fracturesfilled w/ shortite
Ca-dominatedmudstone
Nahcolite nodule
Small saline mineral crystals
Thin saline mineral layers
Dolomite-dominatedmudstone
Named tuff bed
Close-up of cavity, notice how the nodule growth warped and fractured the surrounding sediments.
Photo 1300-306 ftPorous sandstone with mud rip-up clasts
Horsebench Sandstone
} Photo 1
Si- and Ca-dominatedmudstoneSiltstone /vf sandstoneAbundant fracturesfilled w/ shortite
Nahcolite nodule
Small saline mineral crystals
Thin saline mineral layers
Bitumen
Near vertical fracture
Photo 1221-231 ftNahcolite/shortite crystals - partially dissolved
Shortite fracture fill - Bitter Creek outcrop
Operator: U.S. ERDA-LERCLocation: T12S, R24E, Sec. 19, UTM E 648046, UTM N 4402078Cored interval: 91 - 621 ft, 1.8 inch diameterCore location: Utah Core Research Center
South Uinta Basin 12South Uinta Basin 12The South Uinta Basin 12 (SUB 12) core and nearby outcrop sections (Long Draw and Bitter Creek) display how the saline mineral crystals within the Birds Nest aquifer are much smaller to the south, closer to the basin margin; no large saline nodules are present. The SUB 12 core displays a 39-foot zone (202-241 ft) where the <1-inch nahcolite crystals show significant disso-lution indicating that water passes through this section despite the small crystal size. However, only where the large nodules exist farther to the north, is there the possibility of large volume saline water disposal. The smaller saline mineral crystals are not recognized by geophysical log measurements, making core and outcrop the only way to characterize the Birds Nest zone in this area.
A-Groove460 ftMahoganyZone470 ft
B-Groove551 ftUpper R-6559 ft
Big Three332-343 ft
Stillwater362-366 ft
Four Senators382-398 ft
Wavy Tuff436.7-438.5 ft
MahoganyBed 504 ft
R-8surface
Green R
iver Formation - Parachute C
reek Mem
ber
Lithologic Units
Curly Tuff ?548.1-549.3 ft
0 20 40 60 80
Oil Yield - from Fischer Assay (gal/ton)
100
300
400
500
600
Depth (ft)
0
Deltaic Sands577 ft
Saline Zone 132-270 ft
200Significant saline mineral
dissolution 202-241 ft
Top of economicoil shale - 332 ft
Bed 76(178 ft)
clay siltCore Log
m csand
fvf
} Photo 1
Possible Horsebench Ss.
Si- and Ca-dominatedmudstoneSiltstone /vf sandstone
Abundant fracturesfilled w/ shortite
Small saline mineral crystals
Thin saline mineral layers
Bitumen
Near vertical fracture
Named tuff bed
UINTABASIN
Salt Lake City
Project funded by: U.S. Department of Energy - National Energy Technology Laboratory and Utah Geological Survey
Project Web site: http://geology.utah.gov/emp/UBwater_studyProject Web site: http://geology.utah.gov/emp/UBwater_studyMichael D. Vanden Berg, Stephanie Carney, Craig D. Morgan, and Danielle Lehle Utah Geological Survey, Salt Lake City, Utah
Stratigraphic Characterization of the Birds Nest Aquifer in the Uinta Basin, Utah: Updated Research Regarding the Aquifer’s Potential as a Significant Saline Water Disposal Zone Panel 1
ExplanationWell used in study
Disposal well into BN
Horsebench/Saline zone outcrop
Major river
County boundary
Township and range
Mahogany zone outcrop
Overburden contour
ExplanationWell used in study
Disposal well into BN
Horsebench/Saline zone outcrop
Major river
County boundary
Township and range
Mahogany zone outcrop
Overburden contour
4000 ft
3500 ft
3000 ft
2500 ft
2000 ft
1500 ft
4500 ft
4000 ft
3500 ft
3000 ft
2500 ft
2000 ft
1500 ft
1000 ft
500 ft
Transition uncleardue to lack of data
Transition uncleardue to lack of data