CO2 Utilization and Storage in Shale Gas Reservoirs: Experimental Results and Economic Impacts

AbstractNatural gas is considered a cleaner and lower-emission fuel than coal, and its high abundance from advanced drilling techniques has positioned natural gas as a major alternative energy source for the U.S. However, each ton of CO2 emitted from any type of fossil fuel combustion will continue to increase global atmospheric concentrations. One unique approach to reducing anthropogenic CO2 emissions involves coupling CO2 based enhanced gas recovery (EGR) operations in depleted shale gas reservoirs with long-term CO2 storage operations. In this paper, we report unique findings about the interactions between important shale minerals and sorbing gases (CH4 and CO2) and associated economic consequences. Where enhanced condensation of CO2 followed by desorption on clay surface is observed under supercritical conditions, a linear sorption profile emerges for CH4. Volumetric changes to montmorillonites occur during exposure to CO2. Theory-based simulations identify interactions with interlayer cations as energetically favorable for CO2 intercalation. In contrast, experimental evidence suggests CH4 does not occupy the interlayer and has only the propensity for surface adsorption. Mixed CH4:CO2 gas systems, where CH4 concentrations prevail, indicate preferential CO2 sorption as determined by in situ infrared spectroscopy and X-ray diffraction techniques. Collectively, these laboratory studies combined with a cost-based economic analysis provide a basis for identifying favorable CO2-EOR opportunities in previously fractured shale gas reservoirs approaching final stages of primary gas production. Moreover, utilization of site-specific laboratory measurements in reservoir simulators provides insight into optimum injection strategies for maximizing CH4/CO2 exchange rates to obtain peak natural gas production

Abiotic reduction of aquifer materials by dithionite: A promising in-situ remediation technology

Laboratory batch and column experiments were conducted with Hanford sediments to develop the capability to predict (1) the longevity of dithionite in these systems, (2) its efficiency as a reductant of structural iron, and (3) the longevity and reactivity of the reduced iron with soluble inorganic and organic species. After an initial induction period, the loss of dithionite by disproportionation and oxidation could be described by pseudo-first-order (PFO) kinetics. Other than the initial reaction with ferric iron, the primary factor promoting loss of dithionite in this system was disproportion nation via heterogeneous catalysis at mineral surfaces. The efficiency of the reduction of structural iron was nearly 100% for the first fourth of the ferric iron, but declined exponentially with higher degrees of reduction so that 75% of the ferric iron could be reduced. This decrease in reduction efficiency probably was related to differences in the accessibility of ferric iron in the mineral particles, with iron in clay-sized particles being the most accessible and that in silt- and sand-sized particles less accessible. Flow-through column studies showed that a reduced-sediment barrier created in this manner could maintain a reducing environment

Laboratory Testing of Bulk Vitrified Low-Activity Waste Forms to Support the 2005 Integrated Disposal Facility Performance Assessment

The purpose of this report is to document the results from laboratory testing of the bulk vitri-fied (BV) waste form that was conducted in support of the 2005 integrated disposal facility (IDF) performance assessment (PA). Laboratory testing provides a majority of the key input data re-quired to assess the long-term performance of the BV waste package with the STORM code. Test data from three principal methods, as described by McGrail et al. (2000a; 2003a), are dis-cussed in this testing report including the single-pass flow-through test (SPFT) and product con-sistency test (PCT). Each of these test methods focuses on different aspects of the glass corrosion process. See McGrail et al. (2000a; 2003a) for additional details regarding these test methods and their use in evaluating long-term glass performance. In addition to evaluating the long-term glass performance, this report discusses the results and methods used to provided a recommended best estimate of the soluble fraction of 99Tc that can be leached from the engineer-ing-scale BV waste package. These laboratory tests are part of a continuum of testing that is aimed at improving the performance of the BV waste package

Anomalous porosity preservation and preferential accumulation of gas hydrate in the Andaman accretionary wedge, NGHP-01 site 17A

In addition to well established properties that control the presence or absence of the hydrate stability zone, such as pressure, temperature, and salinity, additional parameters appear to influence the concentration of gas hydrate in host sediments. The stratigraphic record at Site 17A in the Andaman Sea, eastern Indian Ocean, illustrates the need to better understand the role pore-scale phenomena play in the distribution and presence of marine gas hydrates in a variety of subsurface settings. In this paper we integrate field-generated datasets with newly acquired sedimentology, physical property, imaging and geochemical data with mineral saturation and ion activity products of key mineral phases such as amorphous silica and calcite, to document the presence and nature of secondary precipitates that contributed to anomalous porosity preservation at Site 17A in the Andaman Sea. This study demonstrates the importance of grain-scale subsurface heterogeneities in controlling the occurrence and distribution of concentrated gas hydrate accumulations in marine sediments, and document the importance that increased permeability and enhanced porosity play in supporting gas concentrations sufficient to support gas hydrate formation. The grain scale relationships between porosity, permeability, and gas hydrate saturation documented at Site 17A likely offer insights into what may control the occurrence and distribution of gas hydrate in other sedimentary settings.This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/marine-and-petroleum-geologyKeywords: Indian Ocean, Porosity, Saturation, Gas hydrate, Grain size, Carbonate, Permeability, Volcanic as

Investigation of Accelerated Casing Corrosion in Two Wells at Waste Management Area A-AX

This report was revised in September 2008 to remove acid-extractable sodium data from Tables 3.13 and 3.14. The sodium data was removed due to potential contamination introduced during the acid extraction process. The rest of the text remains unchanged from the original report issued in August 2005. An overall goal of the Groundwater Performance Assessment Project, led by Pacific Northwest National Laboratory (PNNL) and per guidance in DOE Order 5400.1, includes characterizing and defining trends in the physical, chemical, and biological condition of the environment. To meet these goals, numerous Resource Conservation and Recovery Act (RCRA) monitoring wells have been installed throughout the Hanford Site. In 2003, it was determined that two RCRA monitoring wells (299-E24-19 and 299-E25-46) in Waste Management Area (WMA) A-AX failed due to rapid corrosion of the stainless steel casing over a significant length of the wells. Complete casing corrosion occurred between 276.6 and 277.7 feet below ground surface (bgs) in well 299- E24-19 and from 274.4 to 278.6 feet bgs in well 299-E25-46. CH2M HILL Hanford Group, Inc., asked scientists from PNNL to perform detailed analyses of vadose zone sediment samples collected in the vicinity of the WMA A-AX from depths comparable to those where the rapid corrosion occurred in hopes of ascertaining the cause of the rapid corrosion

Rapid solubility and mineral storage of CO2 in basalt

The long-term security of geologic carbon storage is critical to its success and public acceptance. Much of the security risk associated with geological carbon storage stems from its buoyancy. Gaseous and supercritical CO2 are less dense than formation waters, providing a driving force for it to escape back to the surface. This buoyancy can be eliminated by the dissolution of CO2 into water prior to, or during its injection into the subsurface. The dissolution makes it possible to inject into fractured rocks and further enhance mineral storage of CO2 especially if injected into silicate rocks rich in divalent metal cations such as basalts and ultra-mafic rocks. We have demonstrated the dissolution of CO2 into water during its injection into basalt leading to its geologic solubility storage in less than five minutes and potential geologic mineral storage within few years after injection [1–3]. The storage potential of CO2 within basaltic rocks is enormous. All the carbon released from burning of all fossil fuel on Earth, 5000 GtC, can theoretically be stored in basaltic rocks [4]

Egg rejection in blackbirds Turdus merula: a by-product of conspecific parasitism or successful resistance against interspecific brood parasites?

Traditional theory assumes that egg recognition and rejection abilities arise as a response against interspecific brood parasitism (IBP). However, rejection also appears in some species that are currently not exploited by interspecific parasites, such as Turdus thrushes. Recent evidences suggest that rejection abilities evolved in these species as a response to conspecific brood parasitism (CBP). To test these two alternative hypotheses, we performed an experimental study by parasitizing nests of the common blackbird (Turdus merula) with conspecifics or heterospecific eggs under different risk of parasitism (presence of interspecific or conspecific parasites near the nest). Common blackbird is a potential host of the common cuckoo (Cuculus canorus) but suffers low levels of CBP too. Results: We found that blackbirds were able to recognize and eject heterospecific eggs at high rates whereas most of conspecifics eggs were not recognized and, therefore, accepted. Ejection rates of conspecific eggs did not exceed 13 %, even in situations of high risk of CBP (blackbird female placed near the nest), which contradict the main prediction derived from the CBP hypothesis. Conversely, ejection rates of experimental eggs simulating IBP were much higher (80–100 %). Furthermore, female blackbirds were more aggressive towards cuckoos than towards blackbird dummies. Conclusions: Our results considered together support the IBP hypothesis, indicating that recognition and rejection of parasitic eggs in blackbirds have probably evolved due to previous cuckoo parasitism. The current absence of IBP in blackbirds may be due to the highly efficient rejection abilities in this species. Thus, these abilities have been retained in absence of brood parasitism as a consequence of the low costs involved for blackbirds, resulting in a successful resistance against interspecific brood parasitism.Financial support has been provided by the Consejería Economía, Innovación, Ciencia y Empleo. Junta de Andalucia (research project CVI-6653)

Microstructural mechanisms and advanced characterization of long and small fatigue crack growth in cast A356-T61 aluminum alloys

Fatigue crack growth-based design is a significant modern engineering consideration for the transportation sector, and its implementation requires accurate characterization and understanding of crack propagation mechanisms with respect to microstructure. To support this goal, long and small fatigue crack growth studies were conducted on widely used A356-T6 cast aluminum alloys in various microstructural conditions. Microstructural variations were created through processing and chemistry means in order to systematically investigate the individual and combined effects of the materials’ characteristic microstructural features on fatigue crack growth at all growth stages. Crack growth mechanisms and failure mode transitions are identified with respect to the eutectic Si morphology/distribution and grain structure by fractographic techniques and electron backscatter diffraction. Crack-microstructure interactions were investigated in depth across all crack sizes, and the respective roles of microstructural features were identified experimentally and further corroborated by numerical models. It is concluded that the eutectic Si phase enhances the alloys’ fatigue crack growth resistance in early growth stages (by transferring stresses off of the α-Al matrix), and progressively decreases due to damage localization. In later growth stages, the eutectic Si phase becomes increasingly detrimental to fatigue crack growth resistance because of its inherently low debonding strength and brittle fracture, as evidenced by the crack selectively following eutectic Si colonies

Characterization of Vadose Zone Sediment: Slant Borehole SX-108 in the S-SX Waste Management Area

This report was revised in September 2008 to remove acid-extractable sodium data from Table 4.17. The sodium data was removed due to potential contamination introduced during the acid extraction process. The rest of the text remains unchanged from the original report issued in February 2002. The overall goal of the of the Tank Farm Vadose Zone Project, led by CH2M HILL Hanford Group, Inc., is to define risks from past and future single-shell tank farm activities. To meet this goal, CH2M HILL Hanford Group, Inc., asked scientists from Pacific Northwest National Laboratory to perform detailed analyses on vadose zone sediment from within the S-SX Waste Management Area. This report is the fourth in a series of four reports to present the results of these analyses. Specifically, this report contains all the geologic, geochemical, and selected physical characterization data collected on vadose zone sediment recovered from a slant borehole installed beneath tank SX-108 (or simply SX-108 slant borehole)