Geological Hydrogen Storage: Geochemical Reactivity of Hydrogen with Sandstone Reservoirs
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ABSTRACT:
SUBMITTER: Hassanpouryouzband A
PROVIDER: S-EPMC9274762 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The hyporheic zone (HZ) is the active ecotone between the surface stream and groundwater, where exchanges of nutrients and organic carbon have been shown to stimulate microbial activity and transformations of carbon and nitrogen. To examine the relationship between sediment texture, biogeochemistry, and biological activity in the Columbia River HZ, the grain size distributions for sediment samples were characterized to define geological facies, and the relationships among physical properties of the facies, physicochemical attributes of the local environment, and the structure and activity of associated microbial communities were examined. Mud and sand content and the presence of microbial heterotrophic and nitrifying communities partially explained the variability in many biogeochemical attributes such as C:N ratio and %TOC. Microbial community analysis revealed a high relative abundance of putative ammonia-oxidizing Thaumarchaeota and nitrite-oxidizing Nitrospirae. Network analysis showed negative relationships between sets of co-varying organisms and sand and mud contents, and positive relationships with total organic carbon. Our results indicate grain size distribution is a good predictor of biogeochemical properties, and that subsets of the overall microbial community respond to different sediment texture. Relationships between facies and hydrobiogeochemical properties enable facies-based conditional simulation/mapping of these properties to inform multiscale modeling of hyporheic exchange and biogeochemical processes.
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Project description:The determination of dynamic reserves is important for tight sandstone gas reservoirs in production. Based on the geological and gas data of the Yan'an gas field, the influence of pressure on the properties of natural gas is studied by mathematical methods. At the same time, the modified flowing material balance equation is established considering the changes in gas viscosity and compressibility. The result shows that (1) the viscosity of natural gas increases rapidly with pressure; (2) the deviation factor decreases with pressure (P < 15 MPa) and then increases (P > 15 MPa) with temperature; (3) the compressibility decreases rapidly with pressure and increases with temperature; (4) compared with the results of the material balance method, the average error of the flowing material balance method is 33.95%, and the accuracy of the modified flowing material balance method is higher with an average error of 1.25%; and (5) a large change in the production will affect the accuracy of the modified flowing material balance method, especially a shut-in for a long time before the pressure drop production is calculated at a certain time, so data points that are relatively consistent should be selected as far as possible to calculate the dynamic reserves. The findings of this study can help in the accurate evaluation of dynamic reserves of the tight gas reservoir in the Yan'an gas field and are an important guide for the formulation of a rational plan for the gas reservoir and its economic and efficient development.
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Project description:Microbial abundance and diversity in deep subsurface environments is dependent upon the availability of energy and carbon. However, supplies of oxidants and reductants capable of sustaining life within mafic and ultramafic continental aquifers undergoing low-temperature water-rock reaction are relatively unknown. We conducted an extensive analysis of the geochemistry and microbial communities recovered from fluids sampled from boreholes hosted in peridotite and gabbro in the Tayin block of the Samail Ophiolite in the Sultanate of Oman. The geochemical compositions of subsurface fluids in the ophiolite are highly variable, reflecting differences in host rock composition and the extent of fluid-rock interaction. Principal component analysis of fluid geochemistry and geologic context indicate the presence of at least four fluid types in the Samail Ophiolite ("gabbro," "alkaline peridotite," "hyperalkaline peridotite," and "gabbro/peridotite contact") that vary strongly in pH and the concentrations of H2, CH4, Ca2+, Mg2+, [Formula: see text], [Formula: see text], trace metals, and DIC. Geochemistry of fluids is strongly correlated with microbial community composition; similar microbial assemblages group according to fluid type. Hyperalkaline fluids exhibit low diversity and are dominated by taxa related to the Deinococcus-Thermus genus Meiothermus, candidate phyla OP1, and the family Thermodesulfovibrionaceae. Gabbro- and alkaline peridotite- aquifers harbor more diverse communities and contain abundant microbial taxa affiliated with Nitrospira, Nitrosospharaceae, OP3, Parvarcheota, and OP1 order Acetothermales. Wells that sit at the contact between gabbro and peridotite host microbial communities distinct from all other fluid types, with an enrichment in betaproteobacterial taxa. Together the taxonomic information and geochemical data suggest that several metabolisms may be operative in subsurface fluids, including methanogenesis, acetogenesis, and fermentation, as well as the oxidation of methane, hydrogen and small molecular weight organic acids utilizing nitrate and sulfate as electron acceptors. Dynamic nitrogen cycling may be especially prevalent in gabbro and alkaline peridotite fluids. These data suggest water-rock reaction, as controlled by lithology and hydrogeology, constrains the distribution of life in terrestrial ophiolites.
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Project description:Low salinity waterflooding (LSWF) and its variants also known as smart water or ion tuned water injection have emerged as promising enhanced oil recovery (EOR) methods. LSWF is a complex process controlled by several mechanisms and parameters involving oil, brine, and rock composition. The major mechanisms and processes controlling LSWF are still being debated in the literature. Thus, the establishment of an approach that relates these parameters to the final recovery factor (RFf) is vital. The main objective of this research work was to use a number of artificial intelligence models to develop robust predictive models based on experimental data and main parameters controlling the LSWF determined through sensitivity analysis and feature selection. The parameters include properties of oil, rock, injected brine, and connate water. Different operational parameters were considered to increase the model accuracy as well. After collecting the relevant data from 99 experimental studies reported in the literature, the database underwent a comprehensive and rigorous data preprocessing stage, which included removal of duplicates and low-variance features, missing value imputation, collinearity assessment, data characteristic assessment, outlier removal, feature selection, data splitting (80-20 rule was applied), and data scaling. Then, a number of methods such as linear regression (LR), multilayer perceptron (MLP), support vector machine (SVM), and committee machine intelligent system (CMIS) were used to link 1316 data samples assembled in this research work. Based on the obtained results, the CMIS model was proven to produce superior results compared to its counterparts such that the root mean squared rrror (RMSE) values for both training and testing data are 4.622 and 7.757, respectively. Based on the feature importance results, the presence of Ca2+ in the connate water, Na+ in the injected brine, core porosity, and total acid number of the crude oil are detected as the parameters with the highest impact on the RFf. The CMIS model proposed here can be applied with a high degree of confidence to predict the performance of LSWF in sandstone reservoirs. The database assembled for the purpose of this research work is so far the largest and most comprehensive of its kind, and it can be used to further delineate mechanisms behind LSWF and optimization of this EOR process in sandstone reservoirs.
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Project description:Subsurface sandstone deposits represent globally ubiquitous reservoirs which can potentially provide the characteristics necessary for the effective geological storage of CO2. Geological carbon storage is widely agreed to be a key asset in tackling anthropogenic emissions and climate change to reach a sustainable 'net zero', despite the present financial challenges associated with it. Therefore, improved understanding of the characteristics of the materials in which we plan to store many gigatons of CO2 is critical. Developing cheaper characterisation techniques is therefore crucial to support the global push for net zero. In this work we use digital analysis of 3D microscale X-ray images of a range of sandstone samples to constrain the porosity-permeability relationship and the upper percolation threshold; the point at which near full pore structure connectivity is achieved. This is one of the most significant controls on the viability of carbon storage as a practical solution to achieving net zero. We find that the upper percolation threshold in sandstone occurs at ca. 14% total porosity whilst the relationship between porosity ([Formula: see text]) and permeability ([Formula: see text]) can be defined as [Formula: see text]. The investigation of the upper percolation threshold may allow a target criterion to be designated when assessing potential carbon storage reservoirs, whilst investigation of the porosity-permeability relationship allows for a greater understanding of the fluid flow regimes in the subsurface. By using a digital technique to assess carbon storage reservoir potentiality we show that initial characterisation of reservoirs can be carried out rapidly and relatively economically, prior to further full reservoir characterisation studies. This approach is also non-destructive, allowing samples to be reused and multiple analytical phases performed on the same materials.
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Project description:The oil-based mud filtrate will invade the formation under the overbalanced pressure during drilling operations. As a result, alterations will occur to the nuclear magnetic resonance (NMR) response characteristics of the original formation, causing the relaxation time of the NMR T2 spectrum of the free fluid part to move towards a slower relaxation time. Consequently, the subsequent interpretation and petrophysical evaluation will be heavily impacted. Therefore, the actual measured T2 spectrum needs to be corrected for invasion. For this reason, considering the low-porosity and low-permeability of sandstone gas formations in the East China Sea as the research object, a new method to correct the incorrect shape of the NMR logging T2 spectrum was proposed in three main steps. First, the differences in the morphology of the NMR logging T2 spectrum between oil-based mud wells and water-based mud wells in adjacent wells were analyzed based on the NMR relaxation mechanism. Second, rocks were divided into four categories according to the pore structure, and the NMR logging T2 spectrum was extracted using the multidimensional matrix method to establish the T2 spectrum of water-based mud wells and oil-based mud wells. Finally, the correctness of the method was verified by two T2 spectrum correction examples of oil-based mud wells in the study area. The results show that the corrected NMR T2 spectrum eliminates the influence of oil-based mud filtrate and improves the accuracy of NMR logging for calculating permeability.
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Project description:Wettability alteration (from oil-wet to mixed- or water-wet condition) is the most prominent mechanism in low-salinity water flooding (LSWF) for enhanced oil recovery (EOR) in sandstone reservoirs. Although several factors influence the wettability alteration, many efforts have been made to find the main controlling factor. In this study, the influence of interface properties of sandstone/brine and thermodynamic equilibrium of sandstone minerals were evaluated to understand the wettability alteration during LSWF. A triple-layer surface complexation model built-in PHREEQC was applied to a quartz/brine interface, and the modeling results were verified with zeta potential experimental data. This model was combined with that of kaolinite/brine to predict sandstone/brine interface properties. The measured and predicted sandstone zeta potentials were between those obtained for quartz and kaolinite in the diluted seawater. The predicted surface potential of sandstone together with that of crude oil was used in extended Derjaguin-Landau-Verwey-Overbeek theory to estimate the attractive or repulsive force. Consideration of thermodynamic equilibrium between minerals and solution significantly increased the pH and hence resulted in an increase in negative surface potential in the surface complexation. This provided a strong repulsive force between crude oil and sandstone, thus resulting in a more water-wet condition.
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