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1
Lu, Ning, Edward M. Kwicklis e Joe P. Rousseau. "Determining Fault Permeability from Subsurface Barometric Pressure". Journal of Geotechnical and Geoenvironmental Engineering 127, n. 9 (settembre 2001): 801–8. http://dx.doi.org/10.1061/(asce)1090-0241(2001)127:9(801).
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Gardner, W. Payton, Stephen J. Bauer e Scott Broome. "Investigating Fracture Network Deformation Using Noble Gas Release". Geofluids 2021 (19 maggio 2021): 1–16. http://dx.doi.org/10.1155/2021/6697819.
Testo completoAbstract (sommario):
We investigate deformation mechanics of fracture networks in unsaturated fractured rocks from subsurface conventional detonation using dynamic noble gas measurements and changes in air permeability. We dynamically measured the noble gas isotopic composition and helium exhalation of downhole gas before and after a large subsurface conventional detonation. These noble gas measurements were combined with measurements of the subsurface permeability field from 64 discrete sampling intervals before and after the detonation and subsurface mapping of fractures in borehole walls before well completion. We saw no observable increase in radiogenic noble gas release from either an isotopic composition or a helium exhalation point of view. Large increases in permeability were observed in 13 of 64 discrete sampling intervals. Of the sampling intervals which saw large increases in flow, only two locations did not have preexisting fractures mapped at the site. Given the lack of noble gas release and a clear increase in permeability, we infer that most of the strain accommodation of the fractured media occurred along previously existing fractures, rather than the creation of new fractures, even for a high strain rate event. These results have significant implications for how we conceptualize the deformation of rocks with fracture networks above the percolation threshold, with application to a variety of geologic and geological engineering problems.
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Karlstrom, L., A. Zok e M. Manga. "Near-surface permeability in a supraglacial drainage basin on the Llewellyn Glacier, Juneau Icefield, British Columbia". Cryosphere 8, n. 2 (27 marzo 2014): 537–46. http://dx.doi.org/10.5194/tc-8-537-2014.
Testo completoAbstract (sommario):
Abstract. Supraglacial channel networks link time varying melt production and meltwater routing on temperate glaciers. Such channel networks often include components of both surface transport in streams and subsurface porous flow through near-surface ice, firn or snowpack. Although subsurface transport if present will likely control network transport efficacy, it is the most poorly characterized component of the system. We present measurements of supraglacial channel spacing and network properties on the Juneau Icefield, subsurface water table height, and time variation of hydraulic characteristics including diurnal variability in water temperature. We combine these data with modeling of porous flow in weathered ice to infer near-surface permeability. Estimates are based on an observed phase lag between diurnal water temperature variations and discharge, and independently on measurement of water table surface elevation away from a stream. Both methods predict ice permeability on a 1–10 m scale in the range of 10−10–10−11 m2. These estimates are considerably smaller than common parameterizations of surface water flow on bare ice in the literature, as well as smaller than most estimates of snowpack permeability. For supraglacial environments in which porosity/permeability creation in the subsurface is balanced by porous flow of meltwater, our methods provide an estimate of microscale hydraulic properties from observations of supraglacial channel spacing.
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Miller, Matthew J., Kartic Khilar e H. Scott Fogler. "Aging of Foamed Gel Used for Subsurface Permeability Reduction". Journal of Colloid and Interface Science 175, n. 1 (ottobre 1995): 88–96. http://dx.doi.org/10.1006/jcis.1995.1433.
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Wang, Chenyu, Yan Dong, Jingyu Gao, Handong Tan, Yingge Wang e Weiyu Dong. "Three-Dimensional Forward Modeling and Inversion Study of Transient Electromagnetic Method Considering Inhomogeneous Magnetic Permeability". Applied Sciences 14, n. 24 (13 dicembre 2024): 11660. https://doi.org/10.3390/app142411660.
Testo completoAbstract (sommario):
Traditional studies on Transient Electromagnetic Method (TEM) typically assume that the subsurface medium is non-magnetic. However, in regions with igneous rock accumulations or where the subsurface is rich in ferromagnetic minerals, neglecting the magnetic properties of the underground medium may lead to erroneous interpretations for TEM data. This paper conducts a 3-D TEM forward modeling and inversion study considering the non-uniformity cases of magnetic permeability. 3-D TEM forward modeling employs an edge-based finite element method using unstructured grids and a second-order implicit backward Euler method, achieving a modeling algorithm that simultaneously considers non-uniform models of magnetic permeability and resis-tivity. The accuracy of the modeling algorithm is verified by comparing it with the analytical solution of a homogeneous half-space model and the solution of a 1-D TEM forward modeling algorithm. 3-D TEM inversion employs the L-BFGS algorithm and synthetic examples considering non-uniform magnetic permeability are presented. The inversion results show good recovery for the resistivity and magnetic permeability models. Comparisons with the inversion results that neglect the non-uniformity of magnetic permeability validate the importance of considering the variation of permeability in 3-D TEM forward modeling and inversion.
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Karlstrom, L., A. Zok e M. Manga. "Near-surface permeability in a supraglacial drainage basin on the Llewellyn glacier, Juneau Ice Field, British Columbia". Cryosphere Discussions 7, n. 6 (4 novembre 2013): 5281–306. http://dx.doi.org/10.5194/tcd-7-5281-2013.
Testo completoAbstract (sommario):
Abstract. Supraglacial channel networks link time varying solar forcing and melt water routing on temperate glaciers. We present measurements of supraglacial channel spacing and network properties on the Juneau Icefield, subsurface water table height, and time variation of hydraulic characteristics including diurnal variability in water temperature. We combine these data with modeling of porous flow in weathered ice to infer near-surface permeability. Estimates are based on an observed phase lag between diurnal water temperature variations and discharge, and independently on measurement of water table surface elevation away from a stream. Both methods predict ice permeability on a 1–10 m scale in the range of 10–10–10–11 m2. These estimates are considerably smaller than common parameterizations of surface water flow on bare ice in the literature, as well as smaller than estimates of snowpack permeability. For supraglacial environments in which porosity/permeability creation in the subsurface is balanced by porous flow of melt water, our methods provide an estimate of microscale hydraulic properties from macroscale, remote observations of supraglacial channel spacing.
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Karczmarczyk, Agnieszka. "PHOSPHORUS REMOVAL FROM DOMESTIC WASTEWATER IN HORIZONTAL SUBSURFACE FLOW CONSTRUCTED WETLAND AFTER 8 YEARS OF OPERATION – A CASE STUDY". JOURNAL OF ENVIRONMENTAL ENGINEERING AND LANDSCAPE MANAGEMENT 12, n. 4 (31 dicembre 2004): 126–31. http://dx.doi.org/10.3846/16486897.2004.9636833.
Testo completoAbstract (sommario):
Horizontal subsurface flow constructed wetlands can effectively treat high levels of biochemical oxygen demand (BOD) and suspended solids. They are also effective as phosphorus trap but usually for a short time. This phenomenon was observed in the presented case study, an example of subsurface flow reed bed filled with “improved” site soil where it was assumed that the permeability of bed would increase as a result of reed penetration. Fine grained site soil was initially effective trap for phosphorus from wastewater. However, during operation clogging of bed media proceeded and phosphorus sorption capacity used up. In general, the longevity of subsurface flow wetlands as phosphorus sinks depends on the hydraulic load, phosphorus load and the type of the media used in bed construction. To be effective as phosphorus sorbent, substrate should contain high levels of Ca, Al and Fe oxides and possess suitable sorption capacity, quick time of reaction and suitable permeability.
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Shokrollahi, Amin, Syeda Sara Mobasher, Kofi Ohemeng Kyei Prempeh, Parker William George, Abbas Zeinijahromi, Rouhi Farajzadeh, Nazliah Nazma Zulkifli, Mohammad Iqbal Mahammad Amir e Pavel Bedrikovetsky. "CO2 Storage in Subsurface Formations: Impact of Formation Damage". Energies 17, n. 17 (23 agosto 2024): 4214. http://dx.doi.org/10.3390/en17174214.
Testo completoAbstract (sommario):
The success of CO2 storage projects largely depends on addressing formation damage, such as salt precipitation, hydrate formation, and fines migration. While analytical models for reservoir behaviour during CO2 storage in aquifers and depleted gas fields are widely available, models addressing formation damage and injectivity decline are scarce. This work aims to develop an analytical model for CO2 injection in a layer-cake reservoir, considering permeability damage. We extend Dietz’s model for gravity-dominant flows by incorporating an abrupt permeability decrease upon the gas-water interface arrival in each layer. The exact Buckley-Leverett solution of the averaged quasi-2D (x, z) problem provides explicit formulae for sweep efficiency, well impedance, and skin factor of the injection well. Our findings reveal that despite the induced permeability decline and subsequent well impedance increase, reservoir sweep efficiency improves, enhancing storage capacity by involving a larger rock volume in CO2 sequestration. The formation damage factor d, representing the ratio between damaged and initial permeabilities, varies from 0.016 in highly damaged rock to 1 in undamaged rock, resulting in a sweep efficiency enhancement from 1–3% to 50–53%. The developed analytical model was applied to predict CO2 injection into a depleted gas field.
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Eggertsson, Guðjón H., Jackie E. Kendrick, Joshua Weaver, Paul A. Wallace, James E. P. Utley, John D. Bedford, Michael J. Allen et al. "Compaction of Hyaloclastite from the Active Geothermal System at Krafla Volcano, Iceland". Geofluids 2020 (11 luglio 2020): 1–17. http://dx.doi.org/10.1155/2020/3878503.
Testo completoAbstract (sommario):
Hyaloclastites commonly form high-quality reservoir rocks in volcanic geothermal provinces. Here, we investigated the effects of confinement due to burial following prolonged accumulation of eruptive products on the physical and mechanical evolution of surficial and subsurface (depths of 70 m, 556 m, and 732 m) hyaloclastites from Krafla volcano, Iceland. Upon loading in a hydrostatic cell, the porosity and permeability of the surficial hyaloclastite decreased linearly with mean effective stress, as pores and cracks closed due to elastic (recoverable) compaction up to 22-24 MPa (equivalent to ~1.3 km depth in the reservoir). Beyond this mean effective stress, denoted as P∗, we observed accelerated porosity and permeability reduction with increasing confinement, as the rock underwent permanent inelastic compaction. In comparison, the porosity and permeability of the subsurface core samples were less sensitive to mean effective stress, decreasing linearly with increasing confinement as the samples compacted elastically within the conditions tested (to 40 MPa). Although the surficial material underwent permanent, destructive compaction, it maintained higher porosity and permeability than the subsurface hyaloclastites throughout the experiments. We constrained the evolution of yield curves of the hyaloclastites, subjected to different effective mean stresses in a triaxial press. Surficial hyaloclastites underwent a brittle-ductile transition at an effective mean stress of ~10.5 MPa, and peak strength (differential stress) reached 13 MPa. When loaded to effective mean stresses of 33 and 40 MPa, the rocks compacted, producing new yield curves with a brittle-ductile transition at ~12.5 and ~19 MPa, respectively, but showed limited strength increase. In comparison, the subsurface samples were found to be much stronger, displaying higher strengths and brittle-ductile transitions at higher effective mean stresses (i.e., 37.5 MPa for 70 m sample, >75 MPa for 556 m, and 68.5 MPa for 732 m) that correspond to their lower porosities and permeabilities. Thus, we conclude that compaction upon burial alone is insufficient to explain the physical and mechanical properties of the subsurface hyaloclastites present in the reservoir at Krafla volcano. Mineralogical alteration, quantified using SEM-EDS, is invoked to explain the further reduction of porosity and increase in strength of the hyaloclastite in the active geothermal system at Krafla.
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Izadi, Mohammad, e Ali Ghalambor. "A New Approach in Permeability and Hydraulic-Flow-Unit Determination". SPE Reservoir Evaluation & Engineering 16, n. 03 (4 luglio 2013): 257–64. http://dx.doi.org/10.2118/151576-pa.
Testo completoAbstract (sommario):
Summary Building an integrated subsurface model is one of the main goals of major oil and gas operators to guide the field-development plans. All field-data acquisitions from seismic, well logging, production, and geomechanical monitoring to enhanced-oil-recovery (EOR) operations can be affected by the accurate details incorporated in the subsurface model. Therefore, building a realistic integrated subsurface model of the field and associated operations is essential for a successful implementation of such projects. Furthermore, using a more reliable model can, in turn, provide the basis in the decision-making process for control and remediation of formation damage. One of the key identifiers of the subsurface model is accurately predicting the hydraulic-flow units (HFUs). There are several models currently used in the prediction of these units on the basis of the type of data available. The predictions that used these models differ significantly because of the assumptions made in the derivations. Most of these assumptions do not adequately reflect realistic subsurface conditions, thus increasing the need for better models. A new approach has been developed in this study for predicting the petrophysical properties and improving the reservoir characterization. The Poiseuille flow equation and Darcy equation were coupled, taking into consideration the irreducible water saturation in the pore network. The porous medium was introduced as a domain containing a bundle of tortuous capillary tubes with irreducible water lining the pore wall. A series of routine and special core analysis was performed on 17 Berea sandstone samples, and the petrophysical properties were measured and X-ray diffraction (XRD) analysis was conducted. In building the petrophysical model, it was initially necessary to assume an ideal reservoir with 17 different layers, each layer representing one Berea sample. Afterward, by the iteration and calibration of the laboratory data, the number of HFUs was determined by use of the common HFU model and the proposed model accordingly. A comparative study shows that the new model provides a better distribution of HFUs and prediction of the petrophysical properties. The new model provides a better match with the experimental data collected than the models currently used in the prediction of such parameters. The good agreement observed for the Berea sandstone experimental data and the model predictions by use of the new permeability model shows a wider range of applicability for various reservoir conditions. In addition, the model has been applied to a series of core-analysis data on low-permeability Medina sandstone, Appalachian basin, northwest Pennsylvania. The flow-unit distribution by use of the proposed model shows a better flow-zone distinction, and the permeability/ porosity relationship has a higher confidence coefficient.
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Sekerbayeva, Aigerim, Ali Mortazavi, Randy D. Hazlett e Bahman Bohloli. "Fault Gouge Permeability Under Confined Conditions: An Investigation for CO2 Storage Applications". Energies 18, n. 1 (24 dicembre 2024): 9. https://doi.org/10.3390/en18010009.
Testo completoAbstract (sommario):
This investigation provides an in-depth experimental analysis of the prepared artificial fault gouge material on permeability characteristics as a function of the confining pressures and injection flow rate pertinent to both CO2 storage and subsurface fluid flow that addresses an ultimate challenge in CO2 storage. The purpose of the research is to gain a better understanding of the role of fault gouge material in structuring fluid flow patterns within geological media and improving the safety and efficiency of subsurface storage systems. In order to ensure the reproducibility of the experimental program, fault gouge material that resembled the size distribution and material type observed in the field and reported within the literature was purposefully designed and prepared. A set of core-flooding experiments were conducted to evaluate the relationships between permeability, confining pressure, and fluid flow rates. The subsequently obtained results showed that lower permeability is always the result of increasing confining pressure, highlighting the significance of fault gouge material for controlling fluid flow in fractured rock formations. These conclusions provide novel insights and can be applicable in practice when evaluating the integrity of CO2 storage sites, which calls for knowledge of permeability behavior under high-stress conditions.
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Verweij, J. M., H. J. Simmelink, J. Underschultz e N. Witmans. "Pressure and fluid dynamic characterisation of the Dutch subsurface". Netherlands Journal of Geosciences - Geologie en Mijnbouw 91, n. 4 (dicembre 2012): 465–90. http://dx.doi.org/10.1017/s0016774600000342.
Testo completoAbstract (sommario):
AbstractThis paper presents and discusses the distribution of fluid and leak-off pressure data from the subsurface of onshore and offshore Netherlands in relation to causes of formation fluid overpressure and the permeability framework. The observed fluid pressure conditions demonstrate a clear regional difference between the southern and the north and north-eastern part of the study area. In the southern area, formation fluid pressures are close to normal and well below measured leak-off pressures. In the north, formation fluids are overpressured and may locally even approach the measured leak-off pressures. The regional differences in fluid overpressure can, in large part, be explained by differences in geologic framework and burial history. In the south, relatively low rates of sedimentary loading and the presence of relatively permeable sedimentary units have led to the currently observed normally pressured conditions. In the northern area, relatively rapid Neogene sediment loading plays an important role in explaining the observed overpressure distributions in Cenozoic mudstones, Cretaceous Chalk and Rijnland groups, and probably also in Jurassic units. The permeability framework of the northern and north-eastern area is significantly affected by Zechstein and Triassic salt deposits and structures. These units are characterised by very low permeability and severely restrict fluid flow and pressure dissipation. This has created hydraulically restricted compartments with high overpressures (for example overpressures exceeding 30 MPa in the Lower Germanic Trias Group in the Terschelling Basin and Dutch Central Graben).
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Munadi, Suprajitno. "POSSIBILITY TO ESTIMATE BULK PERMEABILITY FROM SEISMIC DATA". Scientific Contributions Oil and Gas 29, n. 1 (29 marzo 2022): 44–48. http://dx.doi.org/10.29017/scog.29.1.1022.
Testo completoAbstract (sommario):
Permeability is one of the most important reservoir parameter which determines the reserves. Unlike the porosity which is considered to be the static property of oil and gas reservoir, permeability is the dynamic property. It reflects the ability of reservoir rock to transmit fluid (oil gas or water). The reservoir rock is located deep below the subsurface, so that the measurement of the permeability is usually carried out from the cores. So far there is no well logging tool which measures the rock permeability directly. Physically, there is no direct relationship between porosity and permeability, the estimation of permeability from the cross-plot between porosity and permeability is just a rough estimate, but it is usually accepted in practical application. Apart from cross- correlation method, there is now exist a sophisticated approach to estimate permeability based on well log data using artificial neural network. There now exist a method which is widely accepted to estimate the porosity of the subsurface layer using seismic method. This method exploits the relationship between porosity and acoustic impedance of the sub- surface layer. And since acoustic impedance can be derived from the seismic amplitudes, it means that the rock porosity can be estimated from seismic data. A new question can be exposed as follows : "Is there any seismic wave parameter or quantity which is theoretically can be releted to permability ?" (so that the estimation of reservoir permeability can be estimated from seimic data). This paper tries to propose an idea to use a specific seismic wave parameter whis is theoretically can be related to the permeability of a reservoir rock, with a hope that more detail research can be pointed to that direction. This idea is supported by qualitative analysis and some theoretical findings
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Plattenberger, Dan A., Florence T. Ling, Catherine A. Peters e Andres F. Clarens. "Targeted Permeability Control in the Subsurface via Calcium Silicate Carbonation". Environmental Science & Technology 53, n. 12 (28 maggio 2019): 7136–44. http://dx.doi.org/10.1021/acs.est.9b00707.
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Sutherland, Fiona, Dominic Lawrance, Philippe Legrand e Edwin Wraith. "Seismic monitoring for subsurface uncertainties at the Endurance CO2 store". Leading Edge 41, n. 4 (aprile 2022): 253–58. http://dx.doi.org/10.1190/tle41040253.1.
Testo completoAbstract (sommario):
The development of the Endurance structure in the southern North Sea as a CO2 store offers a potentially large decarbonization opportunity for industry along the east coast of England. The Bunter Sandstone Formation in the Endurance structure has been assessed as an excellent candidate for CO2 storage due to its position, depth, reservoir properties, and extensive seal. Monitoring CO2 during active injection and after closure is vital to confirming containment and conformance of the CO2 within the store. There are two key subsurface uncertainties: compartmentalization and vertical permeability. Current seismic resolution does not provide imaging of thin, low-permeability layers that may create low relative vertical permeability, and the high net to gross of the sandstone limits imaging of any minor faulting. However, the strong CO2 response on 4D seismic likely will illuminate baffles and barriers to flow along with variations in reservoir permeability. In 2020, four two-dimensional high-resolution (2DHR) seismic data test lines were acquired to assess the best technology for imaging and monitoring Endurance. High-resolution seismic was concluded to provide quality imaging from the base of the reservoir (approximately 1500 m true vertical depth subsea) up through the overburden to image the entire subsurface and to demonstrate safe storage of CO2.
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Shao, W., T. A. Bogaard, M. Bakker e R. Greco. "Quantification of the influence of preferential flow on slope stability using a numerical modelling approach". Hydrology and Earth System Sciences 19, n. 5 (7 maggio 2015): 2197–212. http://dx.doi.org/10.5194/hess-19-2197-2015.
Testo completoAbstract (sommario):
Abstract. The effect of preferential flow on the stability of landslides is studied through numerical simulation of two types of rainfall events on a hypothetical hillslope. A model is developed that consists of two parts. The first part is a model for combined saturated/unsaturated subsurface flow and is used to compute the spatial and temporal water pressure response to rainfall. Preferential flow is simulated with a dual-permeability continuum model consisting of a matrix domain coupled to a preferential flow domain. The second part is a soil mechanics model and is used to compute the spatial and temporal distribution of the local factor of safety based on the water pressure distribution computed with the subsurface flow model. Two types of rainfall events were considered: long-duration, low-intensity rainfall, and short-duration, high-intensity rainfall. The effect of preferential flow on slope stability is assessed through comparison of the failure area when subsurface flow is simulated with the dual-permeability model as compared to a single-permeability model (no preferential flow). For the low-intensity rainfall case, preferential flow has a positive effect on drainage of the hillslope resulting in a smaller failure area. For the high-intensity rainfall case, preferential flow has a negative effect on the slope stability as the majority of rainfall infiltrates into the preferential flow domain when rainfall intensity exceeds the infiltration capacity of the matrix domain, resulting in larger water pressure and a larger failure area.
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Zhong, Zhi, Timothy R. Carr, Xinming Wu e Guochang Wang. "Application of a convolutional neural network in permeability prediction: A case study in the Jacksonburg-Stringtown oil field, West Virginia, USA". GEOPHYSICS 84, n. 6 (1 novembre 2019): B363—B373. http://dx.doi.org/10.1190/geo2018-0588.1.
Testo completoAbstract (sommario):
Permeability is a critical parameter for understanding subsurface fluid flow behavior, managing reservoirs, enhancing hydrocarbon recovery, and sequestering carbon dioxide. In general, permeability is measured in the laboratory based on subsurface core samples, calculated from well logs or estimated from well tests. However, laboratory measurements and well tests are expensive, time-consuming, and usually limited to a few core samples or wells in a hydrocarbon field or carbon storage site. Machine-learning techniques are good options for generating a rapid, robust, and cost-effective permeability prediction model because of their strengths to recognize the potential interrelationships between input and output variables. Convolutional neural networks (CNN), as a good pattern recognition algorithm, are widely used in image processing, natural language processing, and speech recognition, but are rarely used with regression problems and even less often in reservoir characterization. We have developed a CNN regression model to estimate the permeability in the Jacksonburg-Stringtown oil field, West Virginia, which is a potential carbon storage site and enhanced oil recovery operations field. We also evaluate the concept of the geologic feature image, which is converted from geophysical well logs. Five variables, including two commonly available conventional well logs (the gamma rays [GRs] and bulk density) and three well-log-derived variables (the slopes of the GR and bulk density curves, and shale content), are used to generate a geologic feature image. The CNN treats the geologic feature image as the input and the permeability as the desired output. In addition, the permeability predicted using traditional backpropagation artificial neural networks, which are optimized by genetic algorithms and particle swarm optimization, is compared with the permeability estimated using our CNN. Our results indicate that the CNN regression model provides more accurate permeability predictions than the traditional neural network.
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Wilkins, Scott J., Russell K. Davies e Steve J. Naruk. "Subsurface observations of deformation bands and their impact on hydrocarbon production within the Holstein Field, Gulf of Mexico, USA". Geological Society, London, Special Publications 496, n. 1 (7 agosto 2019): 223–52. http://dx.doi.org/10.1144/sp496-2018-139.
Testo completoAbstract (sommario):
AbstractThe Holstein Field consists of poorly lithified turbidite sands deposited during the Pliocene Epoch. Dense arrays of cataclastic deformation bands have been observed in all cores from wells that penetrate the K2 reservoir sand, the highest density of which are located near the hinge of a monocline. The predominant set of deformation bands strikes parallel to the fold axis, and dips at both high and low angles with respect to bedding. Deformation band orientation and offset of marker beds indicate reverse shear and are consistent with a flexural slip origin during folding. Restorations suggest that the monocline and associated deformation bands formed early during the burial process with high pore pressure.Reservoir permeability estimates from well tests indicate a bulk permeability approximately one-third of the reservoir core permeability in regions with deformation bands, whereas other areas are unaffected. Bulk permeability estimated from the permeability of the reservoir and deformation band network is lower than the reservoir permeability alone, but exceeds the permeability observed in the well tests by a factor of 2. A reduction in permeability of oil relative to water for both the fault and host sand is required to match the well-test permeability with that measured from core.
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Shapiro, Serge A. "A seismic-reflection-based approach for determining the hydraulic permeability of rocks in a subsurface region". Safety of Nuclear Waste Disposal 2 (6 settembre 2023): 77. http://dx.doi.org/10.5194/sand-2-77-2023.
Testo completoAbstract (sommario):
Abstract. The hydraulic permeability of rocks characterizes fluid mobility in the pores of underground reservoirs. Accurate information on this quantity is important for various geotechnology applications with urgent social, environmental and political significance (e.g., the exploration, optimization and monitoring of underground disposals of gases, fluids and radioactive wastes; safe underground engineering operations; and the exploration and development of geothermal and hydrocarbon energy). Because of the high resolution and large penetration range of seismic waves as well as the ability of seismic exploration to operate from the Earth's surface, a seismic-reflection-based method for characterizing underground permeability is very important. The elastic properties of rocks of a given lithology are strongly influenced by the compliant pore space. However, the hydraulic permeability of such rocks can be controlled by compliant pores, stiff pores or both types of pores. Using stress-dependent rock-physics experiments, we derive models of elastic properties (e.g., seismic velocities) as functions of compliant and stiff pore-space geometries. Simultaneously analyzing the stress-dependent behavior of the porosity and of the permeability, we identify which part of the pore space controls the permeability – compliant and/or stiff pore space – and derive a corresponding model. These models are used to directly characterize stiff and compliant pore spaces from seismic velocities and to calculate the underground permeability.
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Shao, W., T. A. Bogaard, M. Bakker e R. Greco. "Quantification of the influence of preferential flow on slope stability using a numerical modeling approach". Hydrology and Earth System Sciences Discussions 11, n. 11 (26 novembre 2014): 13055–99. http://dx.doi.org/10.5194/hessd-11-13055-2014.
Testo completoAbstract (sommario):
Abstract. The effect of preferential flow on the stability of landslides is studied through numerical simulation of two types of rainfall events on a hypothetical hillslope. A model is developed that consists of two parts. The first part is a model for combined saturated/unsaturated subsurface flow and is used to compute the spatial and temporal water pressure response to rainfall. Preferential flow is simulated with a dual-permeability continuum model consisting of a matrix domain coupled to a preferential flow domain. The second part is a~soil mechanics model and is used to compute the spatial and temporal distribution of the local factor of safety based on the water pressure distribution computed with the subsurface flow model. Two types of rainfall events were considered: long duration, low-intensity rainfall, and short duration, high-intensity rainfall. The effect of preferential flow on slope stability is assessed through comparison of the failure area when subsurface flow is simulated with the dual-permeability model as compared to a single-permeability model (no preferential flow). For the low-intensity rainfall case, preferential flow has a positive effect on the slope stability as it drains the water from the matrix domain resulting in a smaller failure area. For the high-intensity rainfall case, preferential flow has a negative effect on the slope stability as the majority of rainfall infiltrates into the preferential flow domain when rainfall intensity exceeds the infiltration capacity of the matrix domain, resulting in larger water pressure and a larger failure area.
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Pertiwi, Tiaraningtias Bagus, Yunus Daud e Fikri Fahmi. "Investigation of Geological Structure Using Magnetotelluric and Gravity Data Optimization on Non Volcanic Geothermal, Bora, Centre of Sulawesi". Journal of Geoscience, Engineering, Environment, and Technology 8, n. 02-2 (31 luglio 2023): 13–17. http://dx.doi.org/10.25299/jgeet.2023.8.02-2.13876.
Testo completoAbstract (sommario):
The existence of geological structures is one of the important parameters in determining the permeability zone in a geothermal system. This research was conducted in a non-volcanic geothermal field, Bora, located in the province of Central Sulawesi, aiming to identify the subsurface features, especially geological structures related to permeability zones by optimizing geophysical data. Magnetotelluric (MT) 3D inversion modelling is some of the latest methods to identify geological structural patterns in geothermal systems. The results of the MT model and analysis its parameters can find variations in the distribution of subsurface resistivity, orientation of the direction of the prospect area, and indications of geological structure zones. The type and geometry of the geological structure associated with the high permeability zone can be complemented by determining the contrast of gravity values and analysis of the maximum First Horizontal Derivative (FHD) and zero of the Second Vertical Derivative (SVD). Based on the analysis of geophysical data, it is possible to identify the permeability zone associated with the main structure, namely the Palu-Koro fault, delineate the geothermal reservoir at a depth of 1500-2000 meters and determine the location of well drilling. To visualize the geothermal system comprehensively, a conceptual model is developed by integrating the geophysical model with geological and geochemical data that are correlated with each other, therefore it can assist in determining the location of production well development.
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Wuave, Terwase. "Effect of Leachate on Soil in Jos Metropolis, Plateau State Nigeria". IOP Conference Series: Earth and Environmental Science 1142, n. 1 (1 marzo 2023): 012058. http://dx.doi.org/10.1088/1755-1315/1142/1/012058.
Testo completoAbstract (sommario):
Abstract Effect leachate on soil quality in Jos is expected because the disposal sites continues to be the major route of infiltration as it affects quality of the area. Six selected disposal sites soil and normal soil were collected local auger at depth range of 1.5 and 3.0 m with distances of 1.0, 1.5,3.0m. The study aim identifies the effect, using PAST statistical software and excel to analyze the results. Particle size of sand has higher percentage with increase porosity from surface to subsurface (surface range 39.54-73.22, subsurface 40.72-73.50). Moisture contents increase from surface to subsurface. Specific gravity decreases from surface to subsurface (surface range 2.58-2.65, subsurface 2.15-2.44). Shear strength result shows increase to subsurface (surface range 15.65-17.43, subsurface 16.34-18.30). Compressibility test result shows slight increase from surface to subsurface. Permeability result show increase from surface to subsurface. Physical characteristics of pH indicate values that are alkaline in nature (surface range 7.2-9.4 subsurface 6.2-8.5). TDS decrease from surface to subsurface (range 143-640, 187-584).EC increase slightly from surface to subsurface (surface range 164-919, subsurface 184-915). Anions result shows chloride have higher concentration at surface (surface range 100-380, subsurface 96-360) while sulphate also have higher concentration on surface than subsurface (surface range 192-270, subsurface 178-225). Cation results shows sodium ion concentration on the surface increase to subsurface (surface range 250-2600, subsurface 265-2705). Potassium concentration also increase on the surface to the subsurface (surface range 172-243, subsurface 186-253) while magnesium ion also increases from surface to subsurface (surface range 3.0-4.4, subsurface 3.7-4.8) and calcium ion shows normal range from surface to subsurface (surface range 10000-12000, subsurface 10000-130000). The heavy metals concentration in the dumpsites soil shows higher values (Ba, Ce, La, Rb, Cr, Th and Fe) in both surface and subsurface above normal soil.
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Ibragimov, Sanjarbek, e Asror Boytemirov. "PREDICTION OF PERMEABILITY OF OIL AND GAS LAYERS USING ARTIFICIAL NEURAL NETWORKS". International Journal of Advance Scientific Research 05, n. 12 (25 dicembre 2024): 290–95. https://doi.org/10.37547/ijasr-04-12-45.
Testo completoAbstract (sommario):
This article focuses on predicting the permeability of oil and gas reservoirs using artificial neural networks (ANN). By utilizing data sets from oil and gas wells, comprehensive preprocessing was conducted, including feature selection, scaling, and normalization to ensure the robustness of the models. The effectiveness of ANN in predicting the permeability of underground formations was evaluated using petrophysical data from wells in the Bukhara-Khiva oil and gas region. A precise permeability prediction model was created using key petrophysical parameters such as gamma rays (GR), resistivity (RT), sonic (DT), density (RHOB), and neutron porosity (NPHI). To enhance model performance, the dataset underwent complete preprocessing, including normalization and feature selection. The model's performance was assessed through MSE, R², and MAE metrics, demonstrating higher accuracy compared to traditional linear regression models. The results indicate that the ANN model provides highly accurate permeability predictions. The findings offer valuable insights for optimizing exploration and production strategies in the oil and gas industry, highlighting the superiority of machine learning and neural network models over traditional methods in subsurface resource evaluation.
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Blazejewski, Ryszard, e Sadzide Murat-Blazejewska. "Soil clogging phenomena in constructed wetlands with subsurface flow". Water Science and Technology 35, n. 5 (1 marzo 1997): 183–88. http://dx.doi.org/10.2166/wst.1997.0193.
Testo completoAbstract (sommario):
The paper presents a short description of soil clogging processes during sewage infiltration as well as a simple theoretical model of sand clogging by suspended solids. The Kozeny-Carman equation was used to investigate the influence of the decreasing porosity due to clogging on the sand permeability. A comparison of the results obtained using the derived theoretical relationships with empirical data showed an acceptable agreement.
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TOYOSHIMA, Masayuki. "Prediction of Subsurface-Layer Permeability of Alluvial Fan by Topographical Analysis". Geographical Review of Japa,. Ser. A, Chirigaku Hyoron 67, n. 2 (1994): 126–36. http://dx.doi.org/10.4157/grj1984a.67.2_126.
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Tao, Zhiyuan, Jeffery P. Fitts e Andres F. Clarens. "Feasibility of Carbonation Reactions to Control Permeability in the Deep Subsurface". Environmental Engineering Science 33, n. 10 (ottobre 2016): 778–90. http://dx.doi.org/10.1089/ees.2016.0026.
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Norman R. Fausey, George S. Taylor e Glenn O. Schwab. "Subsurface Drainage Studies in a Fine Textured Soil with Impaired Permeability". Transactions of the ASAE 29, n. 6 (1986): 1650–53. http://dx.doi.org/10.13031/2013.30367.
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Yan, Wen Hui, Ping Gao e Yong Chen. "Structural Design for Oil Well Pump with Soft Sealing and Small Diameter Piston". Advanced Materials Research 655-657 (gennaio 2013): 359–64. http://dx.doi.org/10.4028/www.scientific.net/amr.655-657.359.
Testo completoAbstract (sommario):
For the low pumping demand of daily production per well of low permeability oilfield, a diameter of 25mm soft sealing small diameter piston-type subsurface pump is designed, and an external traveling valve to ensure that the valve still application of standard parts is adopted, while reducing the pump barrel diameter. In order to solve the problems of pump leakage increasing with wear, automatically compensate for soft seal ring is adopted in piston design. The liquid pressure of the pump barrel is changed in the pump working process, so that the sealing ring is deformed outwardly. When the pump reaches the upper stroke, the gap between the pump barrel and the piston reduced, and further improve the sealing effect. The innovation of structure and the selection of new materials can reduce the difficulty of pump processing, as well as can extend the maintenance cycle. This paper introduces the overall structure and sealing characteristics of soft sealing small diameter piston-type subsurface pump. If the soft sealing small diameter piston-type subsurface pump and real-time variable frequence control technique of pumping unit combined, a more reasonable machine rod pump combination can be provided to achieve ultra-low permeability oilfield stripped well efficiently pumping.
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Bakour, Ahmad, Zhanyu Zhang, Chengxin Zheng, Mohamed A. ALsakran e Mohamad Bakir. "The Study of Subsurface Land Drainage Optimal Design Model". Mathematical Problems in Engineering 2021 (15 giugno 2021): 1–11. http://dx.doi.org/10.1155/2021/8827300.
Testo completoAbstract (sommario):
This paper focused on choosing the best design of subsurface land drainage systems in semiarid areas. The study presented three different soil layers with different hydraulic conductivity and permeability, all layers are below the drain level, and the permeability is increasing with depth. A mathematical model was formulated for the horizontal and vertical drainage optimal design. The result was a nonlinear optimization problem with nonlinear constraints, which required numerical methods for its solution. The purpose of the mathematical model is to find the best values of pipes and tubewells spacing, groundwater table drawdown, and pumps operating hours which leads to a minimum total cost of the subsurface drainage design. A computer code was developed in MATLAB environment and applied to the case study. Results show that the vertical drainage was economically better for the case study drainage network design. And the main factor affecting the mathematical model for both pipe and well drainage was the distance between pipes and tubewells. In addition, considering the lifespan of vertical drainage project, the optimal design involves the minimum possible duration of pumping stations. It is hoped that the proposed optimal mathematical model will present a design methodology by which the costs of all alternative designs can be compared so that the least-cost design is selected.
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Raza, Haris, George Sand França, Eveline Sayão e Victor Vilarrasa. "Earthquakes triggered by the subsurface undrained response to reservoir impoundment at Irapé, Brazil". Solid Earth 15, n. 12 (29 novembre 2024): 1407–17. http://dx.doi.org/10.5194/se-15-1407-2024.
Testo completoAbstract (sommario):
Abstract. The necessity to reduce carbon emissions to mitigate climate change is accelerating the transition from fossil fuels to renewable energy sources. Specifically, hydropower has emerged as a prominent and safe renewable energy source but entails reservoir-triggered seismicity (RTS). This phenomenon causes significant challenges for safe reservoir management. Irapé, in Brazil, is a prominent RTS site where seismicity surged after reservoir filling, with a maximum event of magnitude 3.0 in May 2006, just 6 months after the start of reservoir impoundment. Despite the fact that more than 1 decade has passed since the seismicity occurred, the factors governing these earthquakes and their connection to subsurface rock properties remain poorly understood. Here, we attempt to understand the potential causes of RTS at Irapé Dam, which is the highest dam in Brazil at 208 m and the second highest in South America. Permeability and porosity measurements of cylindrical cores from hard and intact rock samples, which were extracted near the RTS zone by pitting 10 cm from the surface, reveal a low-permeability rock. Porosity values range from 6.3 % to 14.7 %. Only 3 out of the 11 tested samples present permeability above the lowest measurable value of the apparatus (0.002 mD), with the highest permeability being 0.0098 mD. The undrained response of the low-permeability rock placed below the reservoir results in an instantaneous increase in pore pressure and poroelastic stress changes due to elastic compression, which brings potential faults located below the reservoir closer to failure conditions. According to our analytical calculations, the vertical loading caused by the increase of 136 m in the reservoir water level led to a 0.61 MPa pore pressure buildup in response to compression at the depth of the Mw 3.0 earthquake, i.e., 3.88 km, resulting in an increase of 0.75 MPa in the vertical effective stress and of 0.48 MPa in the horizontal effective stress. These changes resulted in an increase in the deviatoric stress that led to fault destabilization, causing the RTS. The laboratory measurements and analytical calculations corroborate the hypothesis that the initial seismic activity was induced by the undrained subsurface response to the reservoir loading at Irapé.
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Vaičiukynas, Vilimantas, Saulius Vaikasas, Henrikas Sivilevičius e Audrius Grinys. "The impact of agriculture drainage reconstruction on ground water recession close to the subgrade". Baltic Journal of Road and Bridge Engineering 10, n. 3 (28 settembre 2015): 230–38. http://dx.doi.org/10.3846/bjrbe.2015.29.
Testo completoAbstract (sommario):
Good drainage is the most important design consideration for a road, both to miniaturize road maintenance costs and maximize the time the road is operational. The lack of good drainage lead to the structural damages and costly repairs. Many of roads are built in intensively drained agricultural land. The effective way to drain subgrades is reconstruction of existing agricultural drainage. The impact of cross-subsurface drainage system on water level fluctuation was measured using Plane geofiltration mathematical model, one of 3D geofiltration modelling programs. The hydraulic permeability characteristics were determined in field of Pikeliai, close to local road in Kėdainiai district, Lithuania. This object is composed of clay and loamy soils. Subsurface cross drains trenches spacing of 20 m, 30 m and 40 m were simulated. The hydraulic permeability of cross drain trenches and lateral trenches modelled was from 0.006 m/a day to 6 m/a day. The simulation of cross drains trenches showed that the most effective distance between them are 20 m. The highest water depression occurs when the permeability of cross drain trenches and lateral trenches is ~ 6 m/day, at the distance of 20 m. The water recession is 20 cm lower compared to the drainage systems without cross drains trenches. By installing cross drains trenches every 30 m, water recession is 10 cm lower when the trench permeability is about 6 m/day. When increasing the distance between the cross drains up to 40 m their influence disappears.
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Ameli, Ali A. "Controls on subsurface transport of sorbing contaminant". Hydrology Research 48, n. 5 (17 settembre 2016): 1226–39. http://dx.doi.org/10.2166/nh.2016.170.
Testo completoAbstract (sommario):
Subsurface transport of a sorbing contaminant is poorly understood and characterized. Here, a new semi-analytical saturated–unsaturated flow and transport model is coupled to a kinetic sorption algorithm to assess the impact of changes in the subsurface permeability architecture and flow rate on sorption characteristics. The model outputs reveal the pronounced effect of the rate of vertical decline in Ks on the frequency of occurrence and spatial distribution of subsurface sorption as well as the timing and rate of sorbing contaminants discharged into stream. Sorption potential is weakened with infiltration rate. The impact of infiltration rate on the decline in sorption potential becomes more accentuated as the degree of subsurface vertical heterogeneity in saturated hydraulic conductivity increases. Porosity pattern also impacts sorption characteristics; but its effects highly depend upon the degree of vertical heterogeneity in Ks. The results and methodology presented in this paper have potential implications for assessing water quality in integrated groundwater–surface water systems as well as designing remediation systems.
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Matsunaga, Yasuo, e Wataru Kanda. "Numerical Modeling of a Volcanic Hydrothermal System Based on Resistivity Structure". Journal of Disaster Research 17, n. 5 (1 agosto 2022): 654–62. http://dx.doi.org/10.20965/jdr.2022.p0654.
Testo completoAbstract (sommario):
Numerical simulation is a useful method for studying the magmatic-hydrothermal systems of volcanoes. However, no comprehensive scheme has been established for constructing subsurface permeability structures that have a significant impact on fluid flow within the volcano. In this study, as a first step to establishing such a scheme, numerical simulations of hydrothermal fluid flow incorporating the heterogeneous properties of the permeability structure were performed utilizing the resistivity structure observed at Kusatsu-Shirane Volcano, central Japan. Although the constructed permeability structure was relatively simple, the simulation results closely reproduced some observations, such as the broad resistivity structure and the distribution and discharge patterns of hot springs around the volcano. These results suggest that the uncertainty in generating permeability structures in hydrothermal fluid flow simulations can be greatly reduced by using resistivity structures.
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Vu, Hung Viet, e Lan Cao Mai. "Appraising and developing ST-X field determination of uncertainties by DST analysis". Science and Technology Development Journal 19, n. 1 (31 marzo 2016): 27–34. http://dx.doi.org/10.32508/stdj.v19i1.502.
Testo completoAbstract (sommario):
A subsurface uncertainties is a possible future event, which, if occurs, would affect project objectives either negatively or positively. For any given model or event, the uncertainty is the range of variation of the component parts and possible outcomes. It could be quantified approximately by either analytical model or in a more cumbersome one such as numerical approach. This paper summarizes thedetermination ofuncertainties by DST analysis in appraising and developing the ST-X gas condensate field, which is offshore Vietnam in Block 15-1O. Drill Stem Test (DST) results show that the S field has moderate to low permeability, multiple flow boundaries/barriers, and at least 2 PVT regions. To understand the impact of these and other important reservoir parameters on ultimate gas and condensate recovery and well count, the uncertainties has to be well evaluated and understood. The study demonstrates that there is a wide range of possible ultimate gas and condensate recoveries and well counts. The top causes for this wide range are permeability and flow boundaries/barriers. In addition to the subsurface risks, drilling cost of a ST-X well is very high. The high well cost in combination with the field being offshore, having low permeability and possibly numerous reservoir compartments dramatically increase the risk of a full field development.
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Al Ismail, Maytham I., e Mark D. Zoback. "Effects of rock mineralogy and pore structure on stress-dependent permeability of shale samples". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 374, n. 2078 (13 ottobre 2016): 20150428. http://dx.doi.org/10.1098/rsta.2015.0428.
Testo completoAbstract (sommario):
We conducted pulse-decay permeability experiments on Utica and Permian shale samples to investigate the effect of rock mineralogy and pore structure on the transport mechanisms using a non-adsorbing gas (argon). The mineralogy of the shale samples varied from clay rich to calcite rich (i.e. clay poor). Our permeability measurements and scanning electron microscopy images revealed that the permeability of the shale samples whose pores resided in the kerogen positively correlated with organic content. Our results showed that the absolute value of permeability was not affected by the mineral composition of the shale samples. Additionally, our results indicated that clay content played a significant role in the stress-dependent permeability. For clay-rich samples, we observed higher pore throat compressibility, which led to higher permeability reduction at increasing effective stress than with calcite-rich samples. Our findings highlight the importance of considering permeability to be stress dependent to achieve more accurate reservoir simulations especially for clay-rich shale reservoirs. This article is part of the themed issue ‘Energy and the subsurface’.
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Jouniaux, L., e F. Zyserman. "Seismo-electrics, electro-seismics, and seismo-magnetics for earth sciences". Solid Earth Discussions 7, n. 3 (18 settembre 2015): 2563–662. http://dx.doi.org/10.5194/sed-7-2563-2015.
Testo completoAbstract (sommario):
Abstract. The seismo-electromagnetic method (SEM) is used for non-invasive subsurface exploration. It shows interesting results for detecting fluids such as water, ice, oil, gas, CO2, and also to better characterise the subsurface in terms of porosity, permeability, and fractures. However, a limitation of this method is the low level of the induced signals. We first describe SEM's theoretical background, and the role of some key parameters. We then detail recent studies on SEM, through theoretical and numerical developments, and through field and laboratory observations, to show that this method can bring advantages compared to classical geophysical methods.
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Jouniaux, L., e F. Zyserman. "A review on electrokinetically induced seismo-electrics, electro-seismics, and seismo-magnetics for Earth sciences". Solid Earth 7, n. 1 (12 febbraio 2016): 249–84. http://dx.doi.org/10.5194/se-7-249-2016.
Testo completoAbstract (sommario):
Abstract. The seismo-electromagnetic method (SEM) can be used for non-invasive subsurface exploration. It shows interesting results for detecting fluids such as water, oil, gas, CO2, or ice, and also help to better characterise the subsurface in terms of porosity, permeability, and fractures. However, the challenge of this method is the low level of the induced signals. We first describe SEM's theoretical background, and the role of some key parameters. We then detail recent studies on SEM, through theoretical and numerical developments, and through field and laboratory observations, to show that this method can bring advantages compared to classical geophysical methods.
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Rose, Kelly Kathleen, Jennifer R. Bauer e MacKenzie Mark-Moser. "A systematic, science-driven approach for predicting subsurface properties". Interpretation 8, n. 1 (1 febbraio 2020): T167—T181. http://dx.doi.org/10.1190/int-2019-0019.1.
Testo completoAbstract (sommario):
As human exploration of the subsurface increases, there is a need for better data- and knowledge-driven methods to improve prediction of subsurface properties. Present subsurface predictions often rely upon disparate and limited a priori information. Even regions with concentrated subsurface exploration still face uncertainties that can obstruct safe and efficient exploration of the subsurface. Uncertainty may be reduced, even for areas with little or no subsurface measurements, using methodical, science-driven geologic knowledge and data. We have developed a hybrid spatiotemporal statistical-geologic approach, subsurface trend analysis (STA), that provides improved understanding of subsurface systems. The STA method assumes that the present-day subsurface is not random, but is a product of its history, which is a sum of its systematic processes. With even limited data and geologic knowledge, the STA method can be used to methodically improve prediction of subsurface properties. To demonstrate and validate the improved prediction potential of the STA method, it was applied in an analysis of the northern Gulf of Mexico. This evaluation was prepared using only existing, publicly available well data and geologic literature. Using the STA method, this information was used to predict subsurface trends for in situ pressure, in situ temperature, porosity, and permeability. The results of this STA-based analysis were validated against new reservoir data. STA-driven results were also contrasted with previous studies. Both indicated that STA predictions were an improvement over other methods. Overall, STA results can provide critical information to evaluate and reduce risks, identify and improve areas of scarce or discontinuous data, and provide inputs for multiscale modeling efforts, from reservoir scale to basin scale. Thereby, the STA method offers an ideal framework for guiding future science-based machine learning and natural language processing to optimize subsurface analyses and predictions.
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Christov, Ivan C., e Hari S. Viswanathan. "Introduction: energy and the subsurface". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 374, n. 2078 (13 ottobre 2016): 20150430. http://dx.doi.org/10.1098/rsta.2015.0430.
Testo completoAbstract (sommario):
This theme issue covers topics at the forefront of scientific research on energy and the subsurface, ranging from carbon dioxide (CO 2 ) sequestration to the recovery of unconventional shale oil and gas resources through hydraulic fracturing. As such, the goal of this theme issue is to have an impact on the scientific community, broadly, by providing a self-contained collection of articles contributing to and reviewing the state-of-the-art of the field. This collection of articles could be used, for example, to set the next generation of research directions, while also being useful as a self-study guide for those interested in entering the field. Review articles are included on the topics of hydraulic fracturing as a multiscale problem, numerical modelling of hydraulic fracture propagation, the role of computational sciences in the upstream oil and gas industry and chemohydrodynamic patterns in porous media. Complementing the reviews is a set of original research papers covering growth models for branched hydraulic crack systems, fluid-driven crack propagation in elastic matrices, elastic and inelastic deformation of fluid-saturated rock, reaction front propagation in fracture matrices, the effects of rock mineralogy and pore structure on stress-dependent permeability of shales, topographic viscous fingering and plume dynamics in porous media convection. This article is part of the themed issue ‘Energy and the subsurface’.
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Seyedpour, S. M., C. Henning, P. Kirmizakis, S. Herbrandt, K. Ickstadt, R. Doherty e T. Ricken. "Uncertainty with Varying Subsurface Permeabilities Reduced Using Coupled Random Field and Extended Theory of Porous Media Contaminant Transport Models". Water 15, n. 1 (31 dicembre 2022): 159. http://dx.doi.org/10.3390/w15010159.
Testo completoAbstract (sommario):
To maximize the usefulness of groundwater flow models for the protection of aquifers and abstraction wells, it is necessary to identify and decrease the uncertainty associated with the major parameters such as permeability. To do this, there is a need to develop set of estimates representing subsurface heterogeneity or representative soil permeability estimates. Here, we use a coupled Random Field and extended Theory of Porous Media (eTPM) simulation to develop a robust model with a good predictive ability that reduces uncertainty. The coupled model is then validated with a physical sandbox experiment. Uncertainty is reduced by using 500 realisations of the permeability parameter using the eTPM approach. A multi-layer contaminant transport scenario with varying permeabilities, similar to what could be expected with shallow alluvial sediments, is simulated. The results show that the contaminant arrival time could be strongly affected by random field realizations of permeability compared with a modelled homogenous permeability parameter. The breakthrough time for heterogeneous permeabilities is shorter than the homogeneous condition. Using the 75% confidence interval (CI), the average contaminant concentration shows 4.4% variation from the average values of the considered area and 8.9% variation in the case of a 95% confidence interval.
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Heijkoop, Selwin, David Rieder, Marcel Moura, Maja Rücker e Catherine Spurin. "A Statistical Analysis of Fluid Interface Fluctuations: Exploring the Role of Viscosity Ratio". Entropy 26, n. 9 (10 settembre 2024): 774. http://dx.doi.org/10.3390/e26090774.
Testo completoAbstract (sommario):
Understanding multiphase flow through porous media is integral to geologic carbon storage or hydrogen storage. The current modelling framework assumes each fluid present in the subsurface flows in its own continuously connected pathway. The restriction in flow caused by the presence of another fluid is modelled using relative permeability functions. However, dynamic fluid interfaces have been observed in experimental data, and these are not accounted for in relative permeability functions. In this work, we explore the occurrence of fluid fluctuations in the context of sizes, locations, and frequencies by altering the viscosity ratio for two-phase flow. We see that the fluctuations alter the connectivity of the fluid phases, which, in turn, influences the relative permeability of the fluid phases present.
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Antoneas, George, e Irene Koronaki. "Geothermal Solutions for Urban Energy Challenges: A Focus on CO2 Plume Geothermal Systems". Energies 17, n. 2 (6 gennaio 2024): 294. http://dx.doi.org/10.3390/en17020294.
Testo completoAbstract (sommario):
The utilization of geological formations, distinguished by natural porosity and permeability and protected by low-permeability caprock, has emerged as an effective strategy for carbon dioxide (CO2) storage. This method significantly contributes to mitigating anthropogenic greenhouse gas emissions and addressing the challenges of climate change. Recent research has unveiled the potential of CO2 to enhance geothermal heat energy extraction in geothermal reservoirs by acting as a subsurface heat exchange fluid. This review paper explores the viability of CO2 in augmenting geothermal heat energy extraction, comparing it to conventional water-based geothermal systems. Special emphasis is placed on CO2 plume geothermal (CPG) systems, characterized by rapid deployment and long-term utilization of geothermal energy resources. With the overarching objective of establishing net-zero energy communities, the analysis of such systems offers a comprehensive understanding of their features, providing a fresh perspective on extracted energy within the context of energy supply in integrated, sustainable energy in built systems. Notably, these systems demonstrate efficacy in meeting the power requirements of an energy community, spanning both distinct heating and electricity needs. However, the key challenge lies in selecting suitable locations. This scientific review aims to comprehend the characteristics of CPG under specific temperature and pressure conditions while optimizing subsurface permeability. This insight is pivotal for identifying future locations for CPG operations with the intent of powering small energy communities.
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Bolourinejad, P., e R. Herber. "Experimental and Modeling Study of Salt Precipitation During Injection of CO2 Contaminated With H2S Into Depleted Gas Fields in the Northeast of the Netherlands". SPE Journal 19, n. 06 (30 aprile 2014): 1058–68. http://dx.doi.org/10.2118/164932-pa.
Testo completoAbstract (sommario):
Summary Depleted gas fields are among the most probable candidates for subsurface storage of carbon dioxide (CO2). With proven reservoir and qualified seal, these fields have retained gas over geological time scales. However, unlike methane, injection of CO2 changes the pH of the brine because of the formation of carbonic acid. Subsequent dissolution/precipitation of minerals changes the porosity/permeability of reservoir and caprock. Thus, for adequate, safe, and effective CO2 storage, the subsurface system needs to be fully understood. An important aspect for subsurface storage of CO2 is purity of this gas, which influences risk and cost of the process. To investigate the effects of CO2 plus impurities in a real case example, we have carried out medium-term (30-day) laboratory experiments (300 bar, 100°C) on reservoir and caprock core samples from gas fields in the northeast of the Netherlands. In addition, we attempted to determine the maximum allowable concentration of one of the possible impurities in the CO2 stream [hydrogen sulfide (H2S)] in these fields. The injected gases—CO2, CO2+100 ppm H2S, and CO2+5,000 ppm H2S—were reacting with core samples and brine (81 g/L Na+, 173 g/L Cl−, 22 g/L Ca2+, 23 g/L Mg2+, 1.5 g/L K+, and 0.2 g/L SO42−). Before and after the experiments, the core samples were analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD) for mineralogical variations. The permeability of the samples was also measured. After the experiments, dissolution of feldspars, carbonates, and kaolinite was observed as expected. In addition, we observed fresh precipitation of kaolinite. However, two significant results were obtained when adding H2S to the CO2 stream. First, we observed precipitation of sulfate minerals (anhydrite and pyrite). This differs from results after pure CO2 injection, where dissolution of anhydrite was dominant in the samples. Second, severe salt precipitation took place in the presence of H2S. This is mainly caused by the nucleation of anhydrite and pyrite, which enabled halite precipitation, and to a lesser degree by the higher solubility of H2S in water and higher water content of the gas phase in the presence of H2S. This was confirmed by the use of CMG-GEM (CMG 2011) modeling software. The precipitation of halite, anhydrite, and pyrite affects the permeability of the samples in different ways. After pure CO2 and CO2+100 ppm H2S injection, permeability of the reservoir samples increased by 10–30% and ≤3%, respectively. In caprock samples, permeability increased by a factor of 3–10 and 1.3, respectively. However, after addition of 5,000 ppm H2S, the permeability of all samples decreased significantly. In the case of CO2+100 ppm H2S, halite, anhydrite, and pyrite precipitation did balance mineral dissolution, causing minimal variation in the permeability of samples.
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Ameli, A. A., N. Amvrosiadi, T. Grabs, H. Laudon, I. F. Creed, J. J. McDonnell e K. Bishop. "Hillslope permeability architecture controls on subsurface transit time distribution and flow paths". Journal of Hydrology 543 (dicembre 2016): 17–30. http://dx.doi.org/10.1016/j.jhydrol.2016.04.071.
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Poulsen, Tjalfe G., Per Moldrup, Anne Thorbjørn e Per Schjønning. "Predicting Air Permeability in Undisturbed, Subsurface Sandy Soils from Air-Filled Porosity". Journal of Environmental Engineering 133, n. 10 (ottobre 2007): 995–1001. http://dx.doi.org/10.1061/(asce)0733-9372(2007)133:10(995).
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Anto-Darkwah, Evans, Takeshi Kurotori, Ronny Pini e Avinoam Rabinovich. "Estimating Three-Dimensional Permeability Distribution for Modeling Multirate Coreflooding Experiments". Sustainability 15, n. 4 (9 febbraio 2023): 3148. http://dx.doi.org/10.3390/su15043148.
Testo completoAbstract (sommario):
Characterizing subsurface reservoirs such as aquifers or oil and gas fields is an important aspect of various environmental engineering technologies. Coreflooding experiments, conducted routinely for characterization, are at the forefront of reservoir modeling. In this work, we present a method to estimate the three-dimensional permeability distribution and characteristic (intrinsic) relative permeability of a core sample in order to construct an accurate model of the coreflooding experiment. The new method improves previous ones by allowing to model experiments with mm-scale accuracy at various injection rates, accounting for variations in capillary–viscous effects associated with changing flow rates. We apply the method to drainage coreflooding experiments of nitrogen and water in two heterogeneous limestone core samples and estimate the subcore scale permeability and relative permeability. We show that the models are able to estimate the saturation distribution and core pressure drop with what is believed to be sufficient accuracy.
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Faybishenko, Boris. "A Concept of Fuzzy Dual Permeability of Fractured Porous Media". Water 15, n. 21 (27 ottobre 2023): 3752. http://dx.doi.org/10.3390/w15213752.
Testo completoAbstract (sommario):
The interpretation of the results of hydrogeological field observations and the modeling of fractured porous subsurface media is often conducted using dual-porosity and/or dual-permeability concepts. These concepts, however, do not consider the effects of spatial and temporal variations and uncertainties, or fuzziness, in the evaluation of the subsurface flow characteristics of fractured porous media. The goal of the paper is to introduce a concept of fuzzy dual permeability of fractured porous media based on the fuzzy system analysis of the results of ponded infiltration tests in fractured basalt. The author revisited the results of the tests conducted in areas close to the Idaho National Laboratory (INL), Idaho, USA: small-scale (approximately 0.5 m2) ponded tests at the Hell’s Half Acre site, mesoscale (56 m2) ponded tests at the Box Canyon site, and a large-scale infiltration test (31,416 m2) at the Radioactive Waste Management Complex at INL. Methods of fuzzy clustering and fuzzy regression were applied to describe the time-depth waterfront penetration and to characterize the phenomena of rapid flow through a predominantly fractured component and slow flow through a predominantly porous matrix component. The concept of fuzzy dual permeability is presented using a series of fuzzy membership functions of the waterfront propagation with depth and time. To describe the time variation of the flux, a fuzzy Horton’s model is presented. The developed concept can be used for the uncertainty quantification in flow and transport in geologic media.
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Lo, Julian, Eki Komara e Widya Utama. "The Analysis of Permeability Influence on CO2 Plume based on Reservoir Simulation". IOP Conference Series: Earth and Environmental Science 1373, n. 1 (1 luglio 2024): 012026. http://dx.doi.org/10.1088/1755-1315/1373/1/012026.
Testo completoAbstract (sommario):
Abstract Permeability is critical in site characterization and geoscience studies for carbon capture and storage projects. There is significant uncertainty of CO2 movement in the subsurface caused by permeability. This study aims to analyze the influence of permeability on the movement of CO2 plumes using a synthetic single-porosity model based on reservoir simulation. By simplifying geomechanics, employing tornado experimental design, as well as utilizing Pearson and Spearman correlations from 30,000 neural network proxy models based on Latin Hypercube and Monte Carlo experimental design, this research successfully explains the impact of permeability on CO2 movement. The reservoir can withstand pressures up to 6500 psi without rock failure. The total CO2 injection with a 90% probability is ∼1.3 TSCF equivalent, with an injection rate of 30 MMSCFD, optimized for a duration of 120 years. Initially, the CO2 movement tends to be upward during injection due to gravitational effects, but over time, it tends to move laterally. Vertical permeability exhibits a negative correlation with total CO2 injection, lateral distribution of CO2 plumes, and CO2 solubility in water. On the other hand, horizontal permeability shows a positive correlation with total CO2 injection. Factors such as perforation location and layer thickness also influence the extent of permeability’s role. However, the lateral and vertical movement of CO2 in this study has not been fully identified, and more complex quantification formulas are needed in commercial simulators. Despite the limitations in data and computational resources, this research successfully explains the movement of CO2 plumes and highlights the importance of other factors such as porosity, perforation location, layer thickness, among others. The recommendations of this study include the use of more complex quantification formulas to model the movement of CO2 plumes, along with increasing the complexity of the model.
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Lagasca, Patrick A., M. Cathryn Ryan e Laurence R. Bentley. "Electrical Imaging of a Shallow Free-Phase Stray Gas Plume from an Abandoned Exploration Well". Geofluids 2021 (22 novembre 2021): 1–15. http://dx.doi.org/10.1155/2021/2224187.
Testo completoAbstract (sommario):
Geophysical imaging of free-phase gas (FPG) within aquifers is an emerging method for understanding the mechanisms controlling stray gas migration from oil and gas wells. Crystal Geyser is an unsealed and partially cased well that transports stray CO2 gas to the shallow subsurface. Accumulations of subsurface CO2 FPG near Crystal Geyser have been inferred, but the actual location and dimensions remained unclear. Here, the subsurface FPG distribution surrounding Crystal Geyser was characterized by interpreting 2D electrical resistivity images with previous drilling records and field mapping. An approximately 70-metre-wide FPG plume was located laterally between Crystal Geyser’s conduit and the Little Grand Wash Fault. The FPG plume spanned the vertical extent of approximately 20 to 55 metres below the ground surface, located within the Slick Rock Member sandstone with the relatively low permeability Earthy Member silty sandstone acting as a caprock. The FPG plume was identified from an anomalously high resistivity zone within the Slick Rock Member that was not caused by lateral lithofacies changes or fault displacement. The conceptual FPG migration pathways beneath Crystal Geyser are presented, based on the interpreted FPG distribution from the electrical resistivity images combined with previous site characterization and the principles of buoyant FPG migration. FPG accumulates within the Slick Rock Member by buoyant up-dip migration beneath siltstone capillary barriers of the Earthy Member. FPG leaks to the ground surface within high permeability preferential pathways along the Little Grand Wash Fault and the conduit of Crystal Geyser.
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Hall, Kevin B., Kenneth E. Williams, Joel L. Gevirtz e Matt J. Croy. "The use of barostratigraphy for identifying and categorizing pressure compartmentalization". Interpretation 2, n. 1 (1 febbraio 2014): SB27—SB44. http://dx.doi.org/10.1190/int-2013-0079.1.
Testo completoAbstract (sommario):
Permeability and geologic time are the primary controlling factors for the generation and dissipation of overpressures. With respect to increasing depth, pressure gradients within any layer may increase, decrease, or remain essentially constant. Pore pressure gradients also vary laterally as a response to changes in permeability, which do not always correspond to seismic or correlation surfaces. In some cases, pressure may not respond at all to the presence of a fault, indicating that the fault zone is permeable and that either vertical or lateral fluid flow has allowed pressure to equilibrate across the fault zone. Some faults act as pressure barriers where an overpressured seal does not allow for fluid flow across the fault zone. Barostratigraphy objectively describes the present-day results of the subsurface processes that create overpressures and those that allow abnormal pressures to be maintained and dissipate. Additionally, barostratigraphy provides a formal method to better categorize pressure compartmentalization by providing a framework for the analysis of the stratigraphic nature of subsurface pressure compartments. It is a classification that systematically arranges and partitions subsurface units based on their inherent properties and pressure attributes. These units are identifiable based on observable criteria. They are correlatable, mappable, and useful in identifying the current pressure conditions in all or part of a basin. The prediction of pore pressure at proposed well locations can be optimized by the use of barostratigraphy, which aids in the analysis of subsurface pressure magnitudes and variation, and in basin modeling. Additionally, an understanding of the hydrocarbon distribution in an area (and prospect risking) is enhanced, as is the analysis of seismic velocities and their impact on imaging due to the close relationship between velocity and effective stress.