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Cynthia A. Rice

Publications and source records attributed to Cynthia A. Rice.

8 recordsLinked to original sources
USGS2012

Hydrologic and geochemical data collected near Skewed Reservoir, an impoundment for coal-bed natural gas produced water, Powder River Basin, Wyoming

The Powder River Structural Basin is one of the largest producers of coal-bed natural gas (CBNG) in the United States. An important environmental concern in the Basin is the fate of groundwater that is extracted during CBNG production. Most of this produced water is disposed of in unlined surface impoundments. A 6-year study of groundwater flow and subsurface water and soil chemistry was conducted at one such impoundment, Skewed Reservoir. Hydrologic and geochemical data collected as part of that study are contained herein. Data include chemistry of groundwater obtained from a network of 21 monitoring wells and three suction lysimeters and chemical and physical properties of soil cores including chemistry of water/soil extracts, particle-size analyses, mineralogy, cation-exchange capacity, soil-water content, and total carbon and nitrogen content of soils.

Wyoming↗
USGS2008

Infiltration from an impoundment for coal‐bed natural gas, Powder River Basin, Wyoming: Evolution of water and sediment chemistry

Development of coal‐bed natural gas (CBNG) in the Powder River Basin, Wyoming, has increased substantially in recent years. Among environmental concerns associated with this development is the fate of groundwater removed with the gas. A preferred water‐management option is storage in surface impoundments. As of January 2007, permits for more than 4000 impoundments had been issued within Wyoming. A study was conducted on changes in water and sediment chemistry as water from an impoundment infiltrated the subsurface. Sediment cores were collected prior to operation of the impoundment and after its closure and reclamation. Suction lysimeters were used to collect water samples from beneath the impoundment. Large amounts of chloride (12,300 kg) and nitrate (13,500 kg as N), most of which accumulated naturally in the sediments over thousands of years, were released into groundwater by infiltrating water. Nitrate was more readily flushed from the sediments than chloride. If sediments at other impoundment locations contain similar amounts of chloride and nitrate, impoundments already permitted could release over 48 × 10 6 kg of chloride and 52 × 10 6 kg of nitrate into groundwater in the basin. A solute plume with total dissolved solid (TDS) concentrations at times exceeding 100,000 mg/L was created in the subsurface. TDS concentrations in the plume were substantially greater than those in the CBNG water (about 2300 mg/L) and in the ambient shallow groundwater (about 8000 mg/L). Sulfate, sodium, and magnesium are the dominant ions in the plume. The elevated concentrations are attributed to cation‐exchange‐enhanced gypsum dissolution. As gypsum dissolves, calcium goes into solution and is exchanged for sodium and magnesium on clays. Removal of calcium from solution allows further gypsum dissolution.

Water Resources Research↗
USGS2008

Chemical and stable isotopic composition of water and gas in the Fort Union Formation of the Powder River Basin, Wyoming and Montana: Evidence for water/rock interaction and the biogenic origin of coalbed natural gas

Significant amounts (> 36 million m3/day) of coalbed methane (CBM) are currently being extracted from coal beds in the Paleocene Fort Union Formation of the Powder River Basin of Wyoming and Montana. Information on processes that generate methane in these coalbed reservoirs is important for developing methods that will stimulate additional production. The chemical and isotopic compositions of gas and ground water from CBM wells throughout the basin reflect generation processes as well as those that affect water/rock interaction. Our study included analyses of water samples collected from 228 CBM wells. Major cations and anions were measured for all samples, δDH2O and δ18OH2O were measured for 199 of the samples, and δDCH4 of gas co-produced with water was measured for 100 of the samples. Results show that (1) water from Fort Union Formation coal beds is exclusively Na–HCO3-type water with low dissolved SO4 content (median < 1 mg/L) and little or no dissolved oxygen (< 0.15 mg/L), whereas shallow groundwater (depth generally < 120 m) is a mixed Ca–Mg–Na–SO4–HCO3 type; (2) water/rock interactions, such as cation exchange on clay minerals and precipitation/dissolution of CaCO3 and SO4 minerals, account for the accumulation of dissolved Na and depletion of Ca and Mg; (3) bacterially-mediated oxidation–reduction reactions account for high HCO3 (270–3310 mg/L) and low SO4 (median < 0.15 mg/L) values; (4) fractionation between δDCH4 (− 283 to − 328 per mil) and δDH2O (− 121 to − 167 per mil) indicates that the production of methane is primarily by biogenic CO2 reduction; and (5) values of δDH2O and δ18OH2O (− 16 to − 22 per mil) have a wide range of values and plot near or above the global meteoric water line, indicating that the original meteoric water has been influenced by methanogenesis and by being mixed with surface and shallow groundwater.

International Journal of Coal Geology↗
USGS2005

Characterization and modes of occurrence of elements in feed coal and coal combustion products from a power plant utilizing low-sulfur coal from the Powder River Basin, Wyoming

The U.S. Geological Survey and the University of Kentucky Center for Applied Energy Research are collaborating with an Indiana utility company to determine the physical and chemical properties of feed coal and coal combustion products from a coal-fired power plant. The Indiana power plant utilizes a low-sulfur (0.23 to 0.47 weight percent S) and lowash (4.9 to 6.3 weight percent ash) subbituminous coal from the Wyodak-Anderson coal zone in the Tongue River Member of the Paleocene Fort Union Formation, Powder River Basin, Wyoming. Based on scanning electron microscope and X-ray diffraction analyses of feed coal samples, two mineral suites were identified: (1) a primary or detrital suite consisting of quartz (including beta-form grains), biotite, feldspar, and minor zircon; and (2) a secondary authigenic mineral suite containing alumino-phosphates (crandallite and gorceixite), kaolinite, carbonates (calcite and dolomite), quartz, anatase, barite, and pyrite. The primary mineral suite is interpreted, in part, to be of volcanic origin, whereas the authigenic mineral suite is interpreted, in part, to be the result of the alteration of the volcanic minerals. The mineral suites have contributed to the higher amounts of barium, calcium, magnesium, phosphorus, sodium, strontium, and titanium in the Powder River Basin feed coals in comparison to eastern coals. X-ray diffraction analysis indicates that (1) fly ash is mostly aluminate glass, perovskite, lime, gehlenite, quartz, and phosphates with minor amounts of periclase, anhydrite, hematite, and spinel group minerals; and (2) bottom ash is predominantly quartz, plagioclase (albite and anorthite), pyroxene (augite and fassaite), rhodonite, and akermanite, and spinel group minerals. Microprobe and scanning electron microscope analyses of fly ash samples revealed quartz, zircon, and monazite, euhedral laths of corundum with merrillite, hematite, dendritic spinels/ferrites, wollastonite, and periclase. The abundant calcium and magnesium mineral phases in the fly ash are attributed to the presence of carbonate, clay, and phosphate minerals in the feed coal and their alteration to new phases during combustion. The amorphous diffraction-scattering maxima or glass 'hump' appears to reflect differences in chemical composition of fly ash and bottom ash glasses. In Wyodak-Anderson fly and bottom ashes, the center point of scattering maxima is due to calcium and magnesium content, whereas the glass 'hump' of eastern fly ash reflects variation in aluminum content. The calcium- and magnesium-rich and alumino-phosphate mineral phases in the coal combustion products can be attributed to volcanic minerals deposited in peat-forming mires. Dissolution and alteration of these detrital volcanic minerals occurred either in the peat-forming stage or during coalification and diagenesis, resulting in the authigenic mineral suite. The presence of free lime (CaO) in fly ash produced from Wyodak-Anderson coal acts as a self-contained 'scrubber' for SO3, where CaO + SO3 form anhydrite either during combustion or in the upper parts of the boiler. Considering the high lime content in the fly ash and the resulting hydration reactions after its contact with water, there is little evidence that major amounts of leachable metals are mobilized in the disposal or utilization of this fly ash.

Scientific Investigations Report↗
USGS2004

Organic and inorganic species in produced water: Implications for water reuse

Currently 20-30 billion barrels of formation water are co-produced annually in the USA with conventional oil and natural gas. The large database on the geochemistry of this produced water shows salinities that vary widely from ~5,000 to >350,000 mg/L TDS. Chloride, Na and Ca are generally the dominant ions, and concentrations of Fe, Mn, B, NH3 and dissolved organics, including, BTEX, phenols and poly aromatic hydrocarbons (PAHs) may be relatively high. Hazardous concentrations of NORMs, including Ra-226 and Rn-222 have been reported in produced water from several states. Coal-bed methane (CBM) wells currently produce close to a billion barrels of water and deliver ~8% of total natural gas. The salinity of this produced water generally is lower than that of water from petroleum wells; salinity commonly is 1,000-20,000 mg/L, but ranges to150,000 mg/L TDS. Most CBM wells produce Na-HCO3-Cl type water that is low in trace metals and has no reported NORMs. This water commonly has no oil and grease and has relatively low DOC, but its organic composition has not been characterized in detail. The water is disposed of by injection into saline aquifers, through evaporation and/or percolation in disposal pits, road spreading, and surface discharge. Water that has an acceptable salinity and sodium absorption ratio (SAR) is considered acceptable for surface discharge and for injection into freshwater aquifers. As an alternative to costly disposal, low salinity produced water is being considered for reclamation, especially in the arid western USA. The cost of reclaiming this water to meet irrigation, industrial and drinking water standards was evaluated in a 10 gpm pilot field study at Placerita oil field, California. This produced water had a low salinity of ~8,000 mg/L, but high concentration of Si and organics. Removal of B, Si, NH3 and especially organics from this water proved difficult, and the estimated treatment cost was high at $0.08-$0.39/bbl for water treated for industrial and municipal uses.

Conference Paper↗
USGS2002

Use of soil leachates to define the extent of brine-contaminated soils at the USGS petroleum environmental research site "B", Osage County, northeastern Oklahoma

Soils at an active oil production site with a history of surface releases of produced water were investigated to determine the chemical signature of salt contamination and the spatial distribution of soil salinity in relation to areas of obvious salt scarring. Grab samples of shallow soil (0-15 cm) and selected soil profiles to depths of 0.6 to 1.7 m were collected onsite and offsite using a 5-cm diameter stainless steel soil auger. Air dried and disaggregated soil from 15 cm intervals (100 g) was mixed with 100 ml of distilled-deionized water to dissolve readily soluble salts. After 24 hours the water was separated by centrifugation followed by filtration through a 0.45 micrometer membrane. Specific conductance was measured immediately. Dissolved chloride (Cl) and sulfate (SO4) were initially estimated with Cl titration strips and turbidimetric measurements respectively. More accurate measurements of dissolved Cl, SO4, and bromide (Br) were later performed by ion chromatography. Brine-contaminated soil was indicated by (1) unusually elevated Cl concentrations or relatively low ratios of conductance/Cl in aqueous leachates compared to leachates of uncontaminated soils, and (2) ratios of Cl/Br in leachates (250± 30) that fall within the range of Cl/Br ratios measured in local produced waters (220-320). Leachates of background soils from the area were characterized by low conductance (sandy soils) or dissolved solids dominated by sulfates (shaley soils). At the study site, the surface (0-15 cm) distribution of elevated soil salinity was largely confined to areas of obvious salt scarring. Within the area of salt scars, elevated salinity persisted to depths of refusal by manual augering. The technique will be applied to deeper samples obtained by mechanical augering or direct push techniques.

Oklahoma↗
USGS2002

Characterization of soils and rock at an active oil production site: Effects of brine and hydrocarbon contamination

An active oil production site (Osage-Skiatook petroleum environmental research Site B) in Osage County, Oklahoma is under study to determine the impacts on soils and rock of brine and hydrocarbon spills. The goals of the soil and rock characterization are to 1) document and identify the type, degree, and areal extent of brine and hydrocarbon releases, 2) understand controls on the movement and retention of brine and hydrocarbons, and 3) determine the role of solid phases, such as clay and iron-bearing minerals, in natural mitigation. The types and amounts of clay minerals and oxidizers (particularly iron) are important because of the capacity of clay minerals to exchange cations that are dissolved in brines and the capacity of reactive ferric iron species to oxidize hydrocarbons. Characterization of soils and rock includes visual and microscopic description, X-ray diffraction of bulk and clay fraction samples, separation of size fractions, determination of cation exchange capacity, bulk chemical composition, and selective extraction of iron species. Results suggest that much of the brine and hydrocarbon contamination occurs in the shallow subsurface (< 240 cm) where the soil profile varies from dark brown topsoil to reddish orange sand to greenish-gray clay. A layer of iron-stained colluvium that is present in the shallow subsurface consists of pebbles and coarse sand and forms an important conduit for fluid movement. Unusually high percentages (as much as 97 % of total iron) of reduced iron may record the passage of hydrocarbon-rich ground water. Clay minerals are abundant in some samples and are dominated by kaolinite, mixed layer illite-smectite, and smectite. The correlation of grain size and clay mineral content with soil leachate results will be discussed and high percentages of sodium on exchange sites in clay are expected in areas of past spills of produced water.

Oklahoma↗