Oil and gas well leakage is of public concern primarily due to the perceived risks of aquifer contamination and greenhouse gas (GHG) emissions. This study examined well leakage data from the British ...Columbia Oil and Gas Commission (BC OGC) to identify leakage pathways and initially quantify incident rates of leakage and GHG emissions from leaking wells. Three types of leakage are distinguished: “surface casing vent flow” (SCVF), “outside the surface casing leakage” (OSCL), and “cap leakage” (CL). In British Columbia (BC), the majority of reported incidents involve SCVF of gases, which does not pose a risk of aquifer contamination but does contribute to GHG emissions. Reported liquid leakage of brines and hydrocarbons is rarer. OSCL and CL of gas are more serious problems due to the risk of long-term leakage from abandoned wells; some were reported to be leaking gas several decades after they were permanently abandoned. According to the requirements of provincial regulation, 21,525 have been tested for leakage. In total, 2,329 wells in BC have had reported leakage during the lifetime of the well. This represents 10.8% of all wells in the assumed test population. However, it seems likely that wells drilled and/or abandoned before 2010 have unreported leakage. In BC, the total GHG emission from gas SCVF is estimated to reach about 75,000 t/y based on the existing inventory calculation; however, this number is likely higher due to underreporting.
El presente artículo muestra la segunda fase de desarrollo de la propuesta de diseño, construcción y evaluación de un generador de hidrógeno para bicicleta que será incorporado a un motor de dos (2) ...tiempos como alternativa de movilidad en la ciudad de Bogotá. La fase 1 consiste en el análisis de mercado que fue presentado y publicado en la edición anterior de la presente revista. El objetivo de este trabajo hace parte del aprovechamiento de H2 para contribuir en el desarrollo de soluciones que mitiguen el impacto ambiental.
Gas hydrates in sustainable chemistry Hassanpouryouzband, Aliakbar; Joonaki, Edris; Vasheghani Farahani, Mehrdad ...
Chemical Society reviews,
08/2020, Letnik:
49, Številka:
15
Journal Article
Recenzirano
Odprti dostop
Gas hydrates have received considerable attention due to their important role in flow assurance for the oil and gas industry, their extensive natural occurrence on Earth and extraterrestrial planets, ...and their significant applications in sustainable technologies including but not limited to gas and energy storage, gas separation, and water desalination. Given not only their inherent structural flexibility depending on the type of guest gas molecules and formation conditions, but also the synthetic effects of a wide range of chemical additives on their properties, these variabilities could be exploited to optimise the role of gas hydrates. This includes increasing their industrial applications, understanding and utilising their role in Nature, identifying potential methods for safely extracting natural gases stored in naturally occurring hydrates within the Earth, and for developing green technologies. This review summarizes the different properties of gas hydrates as well as their formation and dissociation kinetics and then reviews the fast-growing literature reporting their role and applications in the aforementioned fields, mainly concentrating on advances during the last decade. Challenges, limitations, and future perspectives of each field are briefly discussed. The overall objective of this review is to provide readers with an extensive overview of gas hydrates that we hope will stimulate further work on this riveting field.
This review includes the current state of the art understanding and advances in technical developments about various fields of gas hydrates, which are combined with expert perspectives and analyses.
Horizontal drilling and hydraulic fracturing have enhanced energy production but raised concerns about drinking-water contamination and other environmental impacts. Identifying the sources and ...mechanisms of contamination can help improve the environmental and economic sustainability of shale-gas extraction. We analyzed 113 and 20 samples from drinking-water wells overlying the Marcellus and Barnett Shales, respectively, examining hydrocarbon abundance and isotopie compositions (e.g.,C₂H₆/CH₄, δ¹³C-CH₄) and providing, to our knowledge, the first comprehensive analyses of noble gases and their isotopes (e.g., ⁴He, ²⁰Ne, ³⁶Ar) in ground water near shale-gas wells. We addressed two questions. (i) Are elevated levels of hydrocarbon gases in drinking-water aquifers near gas wells natural or anthropogenic? (ii) If fugitive gas contamination exists, what mechanisms cause it? Against a backdrop of naturally occurring salt- and gas-rich groundwater, we identified eight discrete clusters of fugitive gas contamination, seven in Pennsylvania and one in Texas that showed increased contamination through time. Where fugitive gas contamination occurred, the relative proportions of thermogenic hydrocarbon gas (e.g., CH₄, ⁴He) were significantly higher (P < 0.01) and the proportions of atmospheric gases (air-saturated water e.g., N₂, ³⁶Ar) were significantly lower (P < 0.01) relative to background groundwater. Noble gas isotope and hydrocarbon data link four contamination clusters to gas leakage from intermediate-depth strata through failures of annulus cement, three to target production gases that seem to implicate faulty production casings, and one to an underground gas well failure. Noble gas data appear to rule out gas contamination by upward migration from depth through overlying geological strata triggered by horizontal drilling or hydraulic fracturing.
The Upper Paleozoic (Carboniferous to Permian) succession in the east margin of the Ordos Basin in the North China Craton has a potential to contain significant hydrocarbon resources, though ...attention have been mainly attracted for its successful development of coalbed methane (CBM). To improve the previous resource estimates and evaluate the hydrocarbon play possibilities, this study incorporated new discoveries of hydrocarbon units and their stratigraphic relation with source rocks, hydrocarbon migration and trapping configurations. Continuous hydrocarbon accumulation units were identified within the Upper Paleozoic, including the Taiyuan, Shanxi and Xiashihezi formations with great tight gas potential, and the Taiyuan and Shanxi formations also containing shale gas and CBM. Different strata combinations are identified with coal deposition and favour for continuous gas accumulations, including the tidal flat, deltaic and fluvial systems distributed in most of the study areas. Methane was not only generated from the thick coal seams in the Taiyuan and Shanxi formations, but also from shale and dark mudstones. The coal, shale and tight sandstones are proved of remarkable gas content and hydrocarbon indications, and the gas saturation of tight sandstones decreases upward. The stacked deposit combinations vary isochronally in different areas, while the coal seams were developed stably showing good gas sources. Two key stages control the hydrocarbon enrichment, the continuous subsidence from coal forming to Late Triassic and the anomalous paleo‐geothermal event happened in Early Cretaceous, as indicated by the fluid inclusions evidence. Extensive areas show good hydrocarbon development potential presently, and more works should be focused on the evaluation and selection of good reservoir combinations.
Understanding strongly correlated phases of matter, such as the quark-gluon plasma and neutron stars, and in particular the dynamics of such systems, for example, following a Hamiltonian quench (a ...sudden change in some Hamiltonian parameter, such as the strength of interparticle interactions) is a fundamental challenge in modern physics. Ultracold atomic gases are excellent quantum simulators for these problems, owing to their tunable interparticle interactions and experimentally resolvable intrinsic timescales. In particular, they provide access to the unitary regime, in which the interactions are as strong as allowed by quantum mechanics. This regime has been extensively studied in Fermi gases
. The less-explored unitary Bose gases
offer possibilities
such as universal physics controlled solely by the gas density
and new forms of superfluidity
. Here, through momentum- and time-resolved studies, we explore degenerate and thermal homogeneous Bose gases quenched to unitarity. In degenerate samples, we observe universal post-quench dynamics in agreement with the emergence of a prethermal state
with a universal non-zero condensed fraction
. In thermal gases, the dynamic and thermodynamic properties generally depend on the gas density and the temperature, but we find that they can still be expressed in terms of universal dimensionless functions. Surprisingly, we find that the total quench-induced correlation energy is independent of the gas temperature. These measurements provide quantitative benchmarks and challenges for the theory of unitary Bose gases.
•New apparent permeability model to describe gas transport in shale matrix is proposed.•Effects of poromechanics, flow regimes, gas sorption and fractal distribution of microstructures on gas flow ...are considered.•Gas flow behaviours in micropores and microfractures are analyzed and compared.•Results provide new insights for understanding gas transport behaviours in shale reservoirs.
With the rapid development of horizontal well drilling and hydraulic fracturing techniques, shale gas has become a major source of energy in recent years. However, accurately characterizing the gas flow behaviour and predicting the permeability evolution in shale matrix is still a challenge at present due to the existence of complex microstructures and volatile reservoir conditions. In this paper, an improved apparent permeability model is developed to analyze real gas transport through micropores and microfractures in shale formation. This new model is able to consider the combined effects of poromechanics, non-Darcy flow, gas sorption and fractal distribution of microstructures on gas apparent permeability. The results indicate that (1) microfracture aperture decreases more than micropore diameter during reservoir depletion; (2) with pore pressure decreasing, gas apparent permeability will continue to increase for smaller size microstructures while the apparent permeability will first decrease and then rebound for microstructures with larger size; (3) with pore pressure decreasing, the contribution of slip flow decreases while the significance of Knudsen diffusion increases, and the proportion of surface diffusion first increases and then decreases; (4) with microstructure size increasing, the contribution of slip flow at high pore pressure and the significance of Knudsen diffusion at low pore pressure increase, but the proportion of surface diffusion decreases; (5) gas apparent permeability of micropores is larger than that of microfractures when the cross section area is the same, and the larger aspect ratio leads to smaller microfractures permeability.
Methane emissions from U.S. and Canadian natural gas systems appear larger than official estimates.
Natural gas (NG) is a potential “bridge fuel” during transition to a decarbonized energy system: It ...emits less carbon dioxide during combustion than other fossil fuels and can be used in many industries. However, because of the high global warming potential of methane (CH
4
, the major component of NG), climate benefits from NG use depend on system leakage rates. Some recent estimates of leakage have challenged the benefits of switching from coal to NG, a large near-term greenhouse gas (GHG) reduction opportunity (
1
–
3
). Also, global atmospheric CH
4
concentrations are on the rise, with the causes still poorly understood (
4
).
This work investigated the thermo‐economics of gas‐to‐wire as a gas flaring mitigation option in a selected gas production facility, in the Niger Delta region of Nigeria, which flares 294 thousand ...standard cubic feet of natural gas, daily. The thermodynamics and economics aspects of the gas‐to‐wire plant were modeled, and implemented in the Engineering Equation Solver software. The thermodynamics was carried out to ascertain the technical feasibility of the proposed plant, while the economics analysis was done to ensure its cost competitiveness. The findings suggested that 19.2 MW of electricity could be generated from the flare gases. This could be achieved at a life cycle cost of 19.24 billion naira, and a unit cost of energy of 13.47 naira per kWh. Parametric simulation of interest rate, excess combustion air, exit temperature of flue gases, and expansion ratio of gas turbine were also done. Furthermore, the proposed power plant could meet the electricity needs of not less than 60,000 households in Delta State where the gas production facility is located at 550 kWh electricity per capita. The study has shown that gas‐to‐wire is one of the viable approaches to tackle gas flaring activities in Nigeria, to meet both the energy demand of its people and to preserve the environment. Thus, it is recommended that the Federal Government of Nigeria should give gas‐to‐wire a priority in its gas flaring utilization agenda.
This paper presents an overview of semiconductor materials used in gas sensors, their technology, design, and application. Semiconductor materials include metal oxides, conducting polymers, carbon ...nanotubes, and 2D materials. Metal oxides are most often the first choice due to their ease of fabrication, low cost, high sensitivity, and stability. Some of their disadvantages are low selectivity and high operating temperature. Conducting polymers have the advantage of a low operating temperature and can detect many organic vapors. They are flexible but affected by humidity. Carbon nanotubes are chemically and mechanically stable and are sensitive towards NO and NH
, but need dopants or modifications to sense other gases. Graphene, transition metal chalcogenides, boron nitride, transition metal carbides/nitrides, metal organic frameworks, and metal oxide nanosheets as 2D materials represent gas-sensing materials of the future, especially in medical devices, such as breath sensing. This overview covers the most used semiconducting materials in gas sensing, their synthesis methods and morphology, especially oxide nanostructures, heterostructures, and 2D materials, as well as sensor technology and design, application in advance electronic circuits and systems, and research challenges from the perspective of emerging technologies.
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