Groundwater Response of Wasatch and Fort Union Sandstones to Reduced CBM Development in Powder River Basin
More than 36,000 CBNG wells were drilled in the Powder River Basin (PRB) during coal bed natural gas (CBNG) development.
The Wyoming Oil and Gas Conservation Commission reports that from 2001-2014, the PRB produced more than 5.6 trillion
cubic feet of CBNG and nearly 954,000 acre feet of groundwater. As a result, groundwater levels were substantially lowered
in areas undergoing development.
Previously, the WSGS examined groundwater level recovery in the Upper Wyodak coal zone. What is more important to the non-CBNG
groundwater users in the PRB, however, is the potential effect that production has had on water levels in the overlying sandstone
aquifers. Those aquifers provide water to nearly 14,000 permitted groundwater wells designated for domestic, municipal, agricultural,
and livestock uses.
In 2015, average monthly CBNG water production in the PRB had declined by 72 percent over 2006 when water production reached peak
levels. This decline in the volume of co-produced groundwater provides an opportunity to examine groundwater level recovery in
the sandstone aquifers and to evaluate the actual effects of CBNG development on other groundwater users. WSGS is currently
assessing groundwater responses to declining CBNG production at 40 U.S. Bureau of Land Management well sites where water levels
in both coal zone and adjacent sandstone aquifers are monitored.
WSGS will publish the results of this study in early 2017 in a Report of Investigations.
Examination of Faults Near Blacktail Butte
WSGS geologic hazards manager Seth Wittke is investigating the location and offset of faults north and south of Blacktail Butte in eastern Jackson Hole.
The fault strands south of Blacktail Butte are classified as Late Quaternary, while the faults north of the butte are
considered Class B (Late Tertiary/Early Quaternary) structures by the U.S. Geological Survey (USGS). Little to no detailed
studies, including paleoseismic investigations or fault scarp morphology, have been conducted on these fault strands. The
WSGS will utilize LiDAR data in Grand Teton National Park and recent aerial photographs to provide data for revised mapping and
geomorphic interpretation of fault-related features north and south of Blacktail Butte. The report is scheduled to be published in 2017.
Coal geologist Chris Carroll and oil and gas geologist Ranie Lynds are conducting research on the Fort Union Formation in the eastern Greater Green River Basin.
This basin holds potential coal and oil and gas reserves. Coal companies actively mine the Fort Union coals near Rock Springs, and the U.S. Department of Energy
coal gasification pilot studies have been conducted in this area. In addition, there are thousands of existing gas wells within the basin. More than 16,000 wells
are proposed for drilling over the next few years, some of which are targeting the Fort Union Formation.
Carroll and Lynds are gathering data and creating a stratigraphic model of the Fort Union Formation to gain a better understanding of the coal,
sandstone, and shale clastic setting.
This study will consider existing oil and gas exploration targets within the Paleocene-age strata and suggest new ideas for future exploration. This project is
intended as original research to gain knowledge of the stratigraphic architecture for the potential for future coal, and oil, and gas resource development.
The first of two reports on the Fort Union Formation is completed and can be found at: Stratigraphy and Hydrocarbon Potential of the Fort Union and Lance Formations in the Great Divide and Washakie Basins, South-Central Wyoming
Stratigraphic data from both projects will be compiled into the USGS real-time National Coal Resource Data System (NCRDS).
The WSGS maintains the Wyoming part of the national database.
Geochronological Map and Database of Radiometric Data
Geologist Jacob Carnes is heading up a project compiling radiometric data from WSGS projects and other public sources. The new geochronological map and database
will be presented as an interactive ArcGIS online map and as queryable tabular data, and will be periodically updated as new data becomes available.
This database will be a valuable resource to members of industry, academia, and the general public who are interested in the geochronology of Wyoming.
The database is scheduled to be available online in spring 2017.
Wyoming Groundwater Atlas
WSGS is using much of the groundwater information it developed during the last eight years to create an online Wyoming groundwater atlas.
The atlas will include interactive maps of:
- Evapotranspiration, runoff, and recharge estimates for Wyoming by WSGS
- Compiled hydrostratigraphy from State Water Plan Groundwater Technical Memoranda with hydraulic and chemical characteristics
- Hydrologic units with links to state water plans
- Springs (digitized statewide) and general hydrography
- General geology and general reference information
The groundwater atlas will be updated regularly as new information becomes available. The initial release is scheduled for spring 2017.
WSGS natural resource analyst James Stafford is heading up the project.
Online Story Map Under Development to Enhance Tourists' Experience in Wyoming
In an effort to put geologic information about various sites across Wyoming into the hands of visitors, the WSGS is developing
a “story map.” The online feature uses ESRI's GIS tools to combine geospatial data with photos and text to create a multifaceted tour of Wyoming.
The story map’s initial launch will be from the WSGS website and will spotlight eight locations: Old Faithful, Devils Tower, Fossil Butte,
Grand Teton, Hell’s Half Acre, Vedauwoo, Sinks Canyon, and Thermopolis Hot Springs.
By selecting a location on the map, the user will be able to view photos and information about the specific site. In addition to the eight
featured locations, there will be an option for users to read facts about additional sites. There will also be contact information for museums
in the state.
The story map’s launch date is scheduled for spring 2017. It will be available to the public at no charge.
Northeast River Basins Groundwater Technical Memorandum
The river basins of northeastern Wyoming are among the most important drainages in the state; they collectively contain one
quarter of Wyoming’s surface area and much of its energy resources. The northeast river basins include the drainages of the
Little Bighorn, Tongue, Powder, Little Powder, Belle Fourche, Little Missouri, Cheyenne, and Upper Niobrara Rivers. Under
contract to the Wyoming Water Development Office (WWDO), WSGS is developing a groundwater technical memo that defines the geographic
extents of the area’s important aquifers and describes their hydraulic and chemical properties, recharge areas, and estimated
recharge rates. The project also identifies existing groundwater studies and future groundwater development opportunities to satisfy
projected future agricultural, municipal, and industrial demands.
The technical memo represents an intensive collaborative effort among water resource professionals from the WSGS, the WWDO, and the USGS.
Additional contributors include the Wyoming State Engineer’s Office, the Water Resources Data System at the University of Wyoming,
the Wyoming Department of Environmental Quality, and the Wyoming Oil and Gas Conservation Commission. Like previous river basin studies by WSGS, this technical memo will
provide the people of Wyoming with the most current and complete compilation of groundwater information available in a format that
is understandable to water professionals and lay persons alike.
This report will be published in December 2017 and will be available on the Wyoming Water Development Office website and through the Wyoming River Basin Plan portal on the WSGS website.
Industrial Sands Investigation
The WSGS has initiated a statewide project to investigate the locations, availability, and quality of sands that can
be used for the Wyoming oil and gas industry as well as other potential markets.
Industrial sands are commonly used for hydraulic fracturing and in the manufacture of glass. This research will involve
identifying economically viable sand deposits in the state as well as whether the sands from those deposits meet industry quality standards.
For this study, to be published in 2017, WSGS geologist Andrea Loveland will gather samples of sands at various sites throughout the state. Samples will then be analyzed with respect
to industry specifications. A final published report will include a summary of the locations sampled, methodology, and analytical results.
Powder River Basin Groundwater Salinity
Groundwater quality, and subsequently the use(s) for which it is suited, varies widely throughout Wyoming. This is most
evident in the large sedimentary structural basins, where the majority of the state’s population resides and the greater part of
economic activity occurs. An aquifer may produce high quality groundwater suited for human consumption at a basin’s margin while
water pumped from the same aquifer a few miles basinward may be unfit for livestock usage. One measure of water quality is
its “salinity.” Salinity is the amount of dissolved material that remains as residue after the liquid portion of a water sample evaporates.
WSGS hydrogeologists are evaluating groundwater salinities occurring at depths of 5,000 feet or less “below ground surface” (bgs)
in the southern Powder River structural basin (SPRB) of northeastern Wyoming. Special emphasis is placed on saline groundwaters
(TDS ≥ 5,000 mg/L) that may be suited to industrial uses thereby conserving higher quality waters for domestic, agricultural, and
livestock uses. Saline groundwaters are encountered most frequently during oil and gas exploration and production operations in deep
basin aquifers located more than 1,000 feet bgs.
As with its earlier study of salinity in Denver-Julesburg Basin groundwater (Taboga and others, 2015), two methods are utilized to
determine groundwater salinity. First, WSGS will obtain existing water quality data from the USGS Produced Water Database and the
WOGCC Water Analysis Database. Second, using the Static Spontaneous Potential Method, WSGS will estimate TDS levels from spontaneous
potential data obtained from WOGCC oil and gas well logs. The project report will be released in 2017.
The 2016 StateMap award year consists of the following WSGS mapping projects (all at 1:24,000 scale):
- Preliminary surficial geology map of the Muddy Gap area, Fremont and Carbon Counties, Wyoming
- Preliminary bedrock geologic map of the Fort Steele 7.5' quadrangle, Carbon County, Wyoming
- Preliminary bedrock geologic map of the Bridger Pass 7.5' quadrangle, Carbon County, Wyoming
Read more about the StateMap program on the WSGS geologic mapping page.
National Coal Resource Data System (NCRDS)
The WSGS secured multiple five-year federal grants from the USGS cooperative NCRDS program. In 2016, the WSGS coal team
completed the first of a five-year grant to study the coal resources of Wyoming’s producing coal basins. Led by coal
geologist Chris Carroll, this cooperative program with the USGS will produce a stratigraphic database of the coal-bearing
formations of Wyoming. The team collects and maintains a stratigraphic database of coal bed intercepts from coal exploration
and petroleum wells, coal outcrop measured sections, and historic coal mine information.
The coal team is currently working on the Paleocene coals in the Wyoming part of the Greater Green River Basin,
concentrating on the Fort Union Formation of the Great Divide and Washakie Basins. In 2017, the team will correlate coals
in the Green River Basin west of the Rock Springs Uplift, concentrating on mineable coals less than 3,500 feet deep. There
are more than 26,000 points of data in the Wyoming database.
The other five-year grant was awarded to oil and gas geologists Ranie Lynds and Rachel Toner to characterize Wyoming's
unconventional Upper Cretaceous oil and gas reservoirs. They will be developing a statewide spatial database of Wyoming's
unconventional reservoir tops, along with associated well and production attributes. Year 1 of the unconventional NCRDS project
was completed in 2016 and focused specifically on reservoirs in the Denver Basin. Upcoming years 2 and 3 of the project will
concentrate on Powder River Basin reservoirs.
Uranium Resource Study of the Gas Hills Area
This uranium investigation will be a detailed study of the sedimentary petrology, related stratigraphy, structural history, and hydrologic flow history of the
Gas Hills mining district in Fremont and Natrona Counties. Geologist Robert Gregory is leading the investigation, which will involve examining regional
geology and stratigraphy as well as the processes responsible for the development and mineralization of the uranium deposits. Expected completion date is
Mines and Minerals Map
The WSGS is creating an online, interactive mines and mineral map of Wyoming that will display
locations of abandoned and active mines, sample locations for mineral resources and sample
analyses, where available. The GIS-based map will be constructed to allow ongoing updates, similar to the interactive Oil and Gas Map of Wyoming
that launched in 2016. Geologists Wayne Sutherland and Robert Gregory are leading the project.
Gems and minerals geologist Wayne Sutherland is researching occurrences of jade, which is the most famous gemstone in Wyoming.
Nephrite jade, also known as Wyoming Jade, is Wyoming’s state gemstone and first received wide attention in the Granite Mountains area of
central Wyoming in the 1930s. Wyoming Jade is considered to be some of the finest nephrite in the world, and varies from translucent to opaque and ranges in color.
This investigation will discuss the geology, mineralogy, and history of jade in Wyoming, along with its significance as a gemstone.
Unconventional Oil and Gas Resources
WSGS oil and gas geologist Rachel Toner is studying Wyoming's unconventional oil and gas resources. The Powder River
and Denver Basins are the only two basins under extensive development for unconventional oil and gas resources. The tight
Cretaceous sands and shales in these basins have been developed using horizontal well drilling and hydraulic fracturing
techniques. Some of the most prolific unconventional oil and gas-producing formations include:
- Mesaverde (Teapot/Parkman sands)
- Cody/Pierre (Shannon/Sussex sands)