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Aouni A. Lakis - One of the best experts on this subject based on the ideXlab platform.
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Vibration analysis of truncated conical shells subjected to Flowing Fluid
Applied Mathematical Modelling, 2010Co-Authors: Youcef Kerboua, Aouni A. Lakis, M. HmilaAbstract:Abstract A method to predict the dynamic behaviour of anisotropic truncated conical shells conveying Fluid is presented in this paper. It is a combination of finite element method and classical shell theory. The displacement functions are derived from exact solutions of Sanders’ shell equilibrium equations of conical shells. The velocity potential, Bernoulli’s equation and impermeability condition have been applied to the shell–Fluid interface to obtain an explicit expression for Fluid pressure which yields three forces (inertial, centrifugal, Coriolis) of the moving Fluid. To the best of the authors’ knowledge, this paper reports the first comparison made between two works which deal with conical shells subjected to internal Flowing Fluid effects. The results obtained by this method for conical shells with various boundary condition and geometries, in vacuum, fully-filled and when subjected to Flowing Fluid were compared with those of other experimental and numerical investigations and good agreement was obtained.
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Modelling of Plates Subjected to Flowing Fluid Under Various Boundary Conditions
Engineering Applications of Computational Fluid Mechanics, 2008Co-Authors: Youcef Kerboua, Aouni A. Lakis, Marc Thomas, L. MarcouillerAbstract:AbstractElastic structures subjected to Fluid flow undergo a considerable change in their dynamic behavior and can lose their stability. In this article we describe the development of a Fluid-solid finite element to model plates subjected to Flowing Fluid under various boundary conditions. The mathematical model for the structure is developed using a combination of the hybrid finite element method and Sanders’ shell theory. The membrane displacement field is approximated by bilinear polynomials and the transversal displacement by an exponential function. Fluid pressure is expressed by inertial, Coriolis and centrifugal Fluid forces, written respectively as function of acceleration, velocity and transversal displacement. Bernoulli’s equation for the Fluid-solid interface and partial differential equation of potential flow are applied to calculate the Fluid pressure. An impermeability condition ensures contact between the system of plates and the Fluid. Mass and rigidity matrices for each element are calcul...
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Shear deformation in dynamic analysis of anisotropic laminated open cylindrical shells filled with or subjected to a Flowing Fluid
Computer Methods in Applied Mechanics and Engineering, 2001Co-Authors: M.h. Toorani, Aouni A. LakisAbstract:Abstract The free vibration of anisotropic laminated composite, as well as isotropic open or closed, cylindrical shells submerged in and subjected simultaneously to an internal and external incompressible, inviscid Fluid are discussed on the basis of a refined shell theory in which transverse shear deformation and rotary inertia effects are taken into account. The shell may be uniform or non-uniform in the circumferential direction. In this approach, displacements and rotations of the shell and the dynamic pressure of the Fluid are modeled by a hybrid finite-element method. The displacement functions are derived from the exact solution of refined shell equations based on orthogonal curvilinear coordinates. The velocity potential and Bernoulli's equation have been used to describe an expression for Fluid pressure which yields three forces (inertial, centrifugal and Coriolis) of the moving Fluid. The mass, stiffness and damping matrices due to the Fluid effect can be obtained by an analytical integration of the Fluid pressure over the liquid element. Extensive results are given of computations carried out to illustrate the theory and dynamic behavior of open and closed cylindrical shells partially or completely filled with liquid, as well as subjected to a Flowing Fluid. A satisfactory agreement is seen between the numerical results predicted by the present theory and the results of existing available other theories.
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Vibration Analysis of Anisotropic Open Cylindrical Shells Subjected to a Flowing Fluid
Journal of Fluids and Structures, 1997Co-Authors: A. Selmane, Aouni A. LakisAbstract:A theory is presented for the determination of the effects of a Flowing Fluid on the vibration characteristics of an open, anisotropic cylindrical shell submerged and subjected simultaneously to an internal and external flow. The case of an open shell partially or completely filled with liquid is also investigated. The structure may be uniform or nonuniform in the circumferential direction. The formulation used is a combination of finite element method and classical shell theory. The displacement functions are derived from exact solutions of Sanders' shell equations. The velocity potential and Bernoulli's equation for a liquid finite element yield an expression for Fluid pressure as a function of the nodal displacements of the element and three forces (inertial, centrifugal and Coriolis) of the moving Fluid. An analytical integration of the Fluid pressure over the liquid element leads to three components: mass, stiffness and damping matrices. Calculations are given to illustrate the dynamic behaviour of open and closed cylindrical shells subjected to a Flowing Fluid, as well as shells partially or completely filled with liquid. Reasonable agreement is found with other theories and experiments.
Boris Galvan - One of the best experts on this subject based on the ideXlab platform.
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A dynamic heat transfer coefficient between fractured rock and Flowing Fluid
Geothermics, 2017Co-Authors: Thomas Heinze, Sahar Hamidi, Boris GalvanAbstract:Abstract Estimation of heat production remains a major challenge for geothermal industry. In continuum mechanics two main approaches need to be separated to model heat transfer between Fluid and rock: local thermal equilibrium (LTE) and local thermal non-equilibrium (LTNE). While LTNE does not require the strong assumption of instantaneous local thermal equilibrium, the parameters for explicit heat transfer between rock and Fluid are only loosely defined. This work focuses on the heat transfer coefficient between rock walls and Flowing Fluid. Based on an experimental setup with simple geometry and a steady state scenario, we derive a dynamic heat transfer coefficient dependent on fracture aperture, flow velocity and thermal parameters. We compare our model to experimental data and achieve a good agreement for most temperatures. In comparison to a static heat transfer coefficient, a dynamic coefficient changes the Fluid and rock temperature distribution in the fractured system. We then show possible extensions of our dynamic approach with a simulation on reservoir scale. In opposite to existing models and empiric approaches our model intrinsically adjusts to spatial heterogeneity and temporal changes in flow and temperature field. The model is based on well-defined physical parameters which can be easily obtained from standard laboratory tests and dependent on characteristic variables like velocity and rock temperature. Our model can be extended by including more constitutive relationships linking permeability, fracture aperture, Fluid pressure and heat transfer.
Chin-fu Tsang - One of the best experts on this subject based on the ideXlab platform.
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Flowing Fluid electrical conductivity logging of a deep borehole during and following drilling: estimation of transmissivity, water salinity and hydraulic head of conductive zones
Hydrogeology Journal, 2016Co-Authors: Christine Doughty, Chin-fu Tsang, Jan-erik Rosberg, Christopher Juhlin, Patrick F. Dobson, Jens BirkholzerAbstract:Flowing Fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at Are, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better estimates of transmissivity and salinity in the conducting fractures intercepted by the borehole, but also yields the hydraulic head values of these fractures, an important piece of information for the understanding of hydraulic structure of the subsurface. Two additional FFEC logging tests were done about 1 year later, and are used to confirm and refine this analysis. Results show that from 250 to 2,000 m depths, there are seven distinct hydraulically conductive zones with different hydraulic heads and low transmissivity values. For the final test, conducted with a much smaller water-level drawdown, inflow ceased from some of the conductive zones, confirming that their hydraulic heads are below the hydraulic head measured in the wellbore under non-pumped conditions. The challenges accompanying 1-day FFEC logging are summarized, along with lessons learned in addressing them.
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Hydrologic testing during drilling: application of the Flowing Fluid electrical conductivity (FFEC) logging method to drilling of a deep borehole
Hydrogeology Journal, 2016Co-Authors: Chin-fu Tsang, Jan-erik Rosberg, Prabhakar Sharma, Théo Berthet, Christopher Juhlin, Auli NiemiAbstract:Drilling of a deep borehole does not normally allow for hydrologic testing during the drilling period. It is only done when drilling experiences a large loss (or high return) of drilling Fluid due to penetration of a large-transmissivity zone. The paper proposes the possibility of conducting Flowing Fluid electrical conductivity (FFEC) logging during the drilling period, with negligible impact on the drilling schedule, yet providing important information on depth locations of both high- and low-transmissivity zones and their hydraulic properties. The information can be used to guide downhole Fluid sampling and post-drilling detailed testing of the borehole. The method has been applied to the drilling of a 2,500-m borehole at Are, central Sweden, firstly when the drilling reached 1,600 m, and then when the drilling reached the target depth of 2,500 m. Results unveil eight hydraulically active zones from 300 m down to borehole bottom, with depths determined to within the order of a meter. Further, the first set of data allows the estimation of hydraulic transmissivity values of the six hydraulically conductive zones found from 300 to 1,600 m, which are very low and range over one order of magnitude.
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Fluid Dynamics in Complex Fractured‐Porous Systems - Feasibility of Long‐Term Passive Monitoring of Deep Hydrogeology with Flowing Fluid Electric Conductivity Logging Method
Dynamics of Fluids and Transport in Complex Fractured-Porous Systems, 2015Co-Authors: Prabhakar Sharma, Christine Doughty, Chin-fu Tsang, Auli Niemi, Jacob BensabatAbstract:The Flowing Fluid electrical conductivity (FFEC) logging method has been used in deep boreholes to obtain estimates for the transmissivity, salinity of formation water, hydraulic head, and formation water flow rate of hydraulically conducting layers. In this paper, we proposed a modified FFEC logging procedure, involving a setup of a string of EC/T probes in the borehole, to passively monitor long-term temporal changes in local flow rates in a brine formation composed of multiple layers with different transmissivities over a period of months or years. The local flows in the layers can vary over time, for instance, as a result of seasonal or climatic changes. In the case of supercritical CO2 storage in the deep subsurface, the local flow pattern of the storage formation will be disturbed and furthermore it may change with time as the low density and low viscosity CO2 enters more and more into the transmissive layers and interacts with in situ water and rock. The present paper explores the possibility of using the FFEC method for such long-term monitoring in an observation well. The feasibility is demonstrated with field data from the Outokumpu test site in Finland.
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Flowing Fluid electric conductivity logging for a deep artesian well in fractured rock with regional flow
Journal of Hydrology, 2013Co-Authors: Christine Doughty, Chin-fu Tsang, Satoshi Yabuuchi, Takanori KunimaruAbstract:The Flowing Fluid electric conductivity (FFEC) logging method is a well-logging technique that may be used to estimate flow rate, salinity, transmissivity, and hydraulic head of individual fractures or high-permeability zones intersected by a wellbore. Wellbore Fluid is first replaced with Fluid of a contrasting electric conductivity, then repeated FEC logging is done while the well is pumped. Zones where Fluid flows into the wellbore show peaks in the FEC logs, which may be analyzed to infer inflow rate and salinity of the individual fractures. Conducting the procedure with two or more pumping rates (multi-rate FFEC logging) enables individual fracture transmissivity and hydraulic head to be determined. Here we describe the first application of the multi-rate FFEC logging method to an artesian well, using a 500-m well in fractured rock at Horonobe, Japan. An additional new factor at the site is the presence of regional groundwater flow, which heretofore has only been studied with synthetic data. FFEC logging was conducted for two different pumping rates. Several analysis techniques had to be adapted to account for the artesian nature of the well. The results were subsequently compared with independent salinity measurements and transmissivity and hydraulic head values obtained from packer tests in the same well. Despite non-ideal operating conditions, multi-rate FFEC logging successfully determined flow rate, salinity, and transmissivity of 17 conducting fractures intercepted by the logged section of the borehole, including two fractures with regional groundwater flow. Predictions of hydraulic head were less accurate, a not unexpected result in light of operational problems and the form of the equation for hydraulic head, which involves the difference between two uncertain quantities. This study illustrates the strengths and weaknesses of the multi-rate FFEC logging method applied to artesian wells. In conjunction with previous studies, it demonstrates the usefulness of the method for a broad range of conditions encountered in subsurface fractured rock.
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Flowing Fluid Electric Conductivity logging method as a tool to characterize the hydraulic conducitivity strucure of a target layer for CO2 injection
European geosciences union general assembly, 2011Co-Authors: Prabhakar Sharma, Chin-fu Tsang, Auli Niemi, Fritjof Fagerlund, Jacob Bensabat, Philippe PezardAbstract:Understanding of the detailed permeability structure and internal heterogeneity of the target layers of CO2injection is important for any successful injection project. Yet, determining this structure by traditional hydraulictesting may be prohibitively cumbersome and expensive, while information obtained from core logs may not givea full picture of the connected permeability.Flowing FEC (Fluid electric conductivity) method provides a quick way of determining the hydraulic conductivitystructure of a reservoir layer. In combination with traditional pumping tests that can provide overallinterval transmissivities, the method can be used for obtaining a more detailed picture of the distribution of thetransmissivities, information that is crucial for CO2 injection experiments where the internal heterogeneity of thetarget layer may greatly influence the distribution of CO2. The method has been previously been successfullyapplied to several applications, ranging from granitic rock to mudstone formations (Doughty et al., 2008; Tsangand Doughty, 2003) and is here being used for preliminary hydraulic characterization of the target CO2 injectionlayer of the Heletz, Israel, the main injection site of the MUSTANG project.In this approach the wellbore water is first replaced by water of a constant salinity distinctly different fromthat of formation water. Next, the well is shut in and an electric conductivity probe is used to scan the FEC ofborehole Fluid as a function of depth. After this, the well is pumped at constant rate, during which a series FEClogs at successive times are obtained. At depth locations where water enters the borehole, the logs display peaks.Analysis of the time evolution and skewness of these peaks allows estimation of the flow rate qi and salinity C,and further, if two or more logs are taken at different well flow rates, the initial ambient pressure heads hi of eachindividual inflow/feed point I can also be estimated. The depth resolution of the inflow locations is typically 10cm.These data can used to define the detailed transmissivity/permeability structure of the reservoir layer.The present presentation discusses the application of the method for characterizing the target layer of the Heletzinjection experiment, in terms of the data, model analysis and comparison of the results to those from core samples.Tsang, C. F. and C. Doughty, Multirate Flowing Fluid electric conductivity logging method, Water ResourcesResearch, 39, 12, 1354-1362 (10.1029/2003WR002308), 2003.Doughty, C., C.-F. Tsang, K. Hatanaka, S. Yabuuchi, and H. Kurikami. Application of direct-fitting, massintegral, and multirate methods to analysis of Flowing Fluid electric conductivity logs from Horonobe, Japan,WaterResour. Res., Vol. 44, doi:10.1029/2007WR006441, 2008.
Marco Martins Afonso - One of the best experts on this subject based on the ideXlab platform.
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the terminal velocity of sedimenting particles in a Flowing Fluid
Journal of Physics A, 2008Co-Authors: Marco Martins AfonsoAbstract:The influence of an underlying carrier flow on the terminal velocity of sedimenting particles is investigated both analytically and numerically. Our theoretical framework works for a general class of (laminar or turbulent) velocity fields and, by means of an ordinary perturbation expansion at small Stokes number, leads to closed partial differential equations (PDE) whose solutions contain all relevant information on the sedimentation process. The set of PDE is solved by means of direct numerical simulations for a class of 2D cellular flows (static and time dependent) and the resulting phenomenology is analysed and discussed.
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On the terminal velocity of sedimenting particles in a Flowing Fluid
Journal of Physics A: Mathematical and Theoretical, 2008Co-Authors: Marco Martins AfonsoAbstract:The influence of an underlying carrier flow on the terminal velocity of sedimenting particles is investigated both analytically and numerically. Our theoretical framework works for a general class of (laminar or turbulent) velocity fields and, by means of an ordinary perturbation expansion at small Stokes number, leads to closed partial differential equations (PDE) whose solutions contain all relevant information on the sedimentation process. The set of PDE's are solved by means of direct numerical simulations for a class of 2D cellular flows (static and time dependent) and the resulting phenomenology is analysed and discussed.
Christine Doughty - One of the best experts on this subject based on the ideXlab platform.
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Flowing Fluid electrical conductivity logging of a deep borehole during and following drilling: estimation of transmissivity, water salinity and hydraulic head of conductive zones
Hydrogeology Journal, 2016Co-Authors: Christine Doughty, Chin-fu Tsang, Jan-erik Rosberg, Christopher Juhlin, Patrick F. Dobson, Jens BirkholzerAbstract:Flowing Fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at Are, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better estimates of transmissivity and salinity in the conducting fractures intercepted by the borehole, but also yields the hydraulic head values of these fractures, an important piece of information for the understanding of hydraulic structure of the subsurface. Two additional FFEC logging tests were done about 1 year later, and are used to confirm and refine this analysis. Results show that from 250 to 2,000 m depths, there are seven distinct hydraulically conductive zones with different hydraulic heads and low transmissivity values. For the final test, conducted with a much smaller water-level drawdown, inflow ceased from some of the conductive zones, confirming that their hydraulic heads are below the hydraulic head measured in the wellbore under non-pumped conditions. The challenges accompanying 1-day FFEC logging are summarized, along with lessons learned in addressing them.
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Fluid Dynamics in Complex Fractured‐Porous Systems - Feasibility of Long‐Term Passive Monitoring of Deep Hydrogeology with Flowing Fluid Electric Conductivity Logging Method
Dynamics of Fluids and Transport in Complex Fractured-Porous Systems, 2015Co-Authors: Prabhakar Sharma, Christine Doughty, Chin-fu Tsang, Auli Niemi, Jacob BensabatAbstract:The Flowing Fluid electrical conductivity (FFEC) logging method has been used in deep boreholes to obtain estimates for the transmissivity, salinity of formation water, hydraulic head, and formation water flow rate of hydraulically conducting layers. In this paper, we proposed a modified FFEC logging procedure, involving a setup of a string of EC/T probes in the borehole, to passively monitor long-term temporal changes in local flow rates in a brine formation composed of multiple layers with different transmissivities over a period of months or years. The local flows in the layers can vary over time, for instance, as a result of seasonal or climatic changes. In the case of supercritical CO2 storage in the deep subsurface, the local flow pattern of the storage formation will be disturbed and furthermore it may change with time as the low density and low viscosity CO2 enters more and more into the transmissive layers and interacts with in situ water and rock. The present paper explores the possibility of using the FFEC method for such long-term monitoring in an observation well. The feasibility is demonstrated with field data from the Outokumpu test site in Finland.
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Flowing Fluid electric conductivity logging for a deep artesian well in fractured rock with regional flow
Journal of Hydrology, 2013Co-Authors: Christine Doughty, Chin-fu Tsang, Satoshi Yabuuchi, Takanori KunimaruAbstract:The Flowing Fluid electric conductivity (FFEC) logging method is a well-logging technique that may be used to estimate flow rate, salinity, transmissivity, and hydraulic head of individual fractures or high-permeability zones intersected by a wellbore. Wellbore Fluid is first replaced with Fluid of a contrasting electric conductivity, then repeated FEC logging is done while the well is pumped. Zones where Fluid flows into the wellbore show peaks in the FEC logs, which may be analyzed to infer inflow rate and salinity of the individual fractures. Conducting the procedure with two or more pumping rates (multi-rate FFEC logging) enables individual fracture transmissivity and hydraulic head to be determined. Here we describe the first application of the multi-rate FFEC logging method to an artesian well, using a 500-m well in fractured rock at Horonobe, Japan. An additional new factor at the site is the presence of regional groundwater flow, which heretofore has only been studied with synthetic data. FFEC logging was conducted for two different pumping rates. Several analysis techniques had to be adapted to account for the artesian nature of the well. The results were subsequently compared with independent salinity measurements and transmissivity and hydraulic head values obtained from packer tests in the same well. Despite non-ideal operating conditions, multi-rate FFEC logging successfully determined flow rate, salinity, and transmissivity of 17 conducting fractures intercepted by the logged section of the borehole, including two fractures with regional groundwater flow. Predictions of hydraulic head were less accurate, a not unexpected result in light of operational problems and the form of the equation for hydraulic head, which involves the difference between two uncertain quantities. This study illustrates the strengths and weaknesses of the multi-rate FFEC logging method applied to artesian wells. In conjunction with previous studies, it demonstrates the usefulness of the method for a broad range of conditions encountered in subsurface fractured rock.
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Application of direct‐fitting, mass integral, and multirate methods to analysis of Flowing Fluid electric conductivity logs from Horonobe, Japan
Water Resources Research, 2008Co-Authors: Christine Doughty, Chin-fu Tsang, Satoshi Yabuuchi, Koichiro Hatanaka, Hiroshi KurikamiAbstract:[1] The Flowing Fluid electric conductivity (FFEC) logging method is an efficient way to provide information on the depths, salinities, and inflow strengths of individual conductive features intercepted by a borehole, without the use of specialized probes. Using it in a multiple-flow rate mode allows, in addition, an estimate of the transmissivities and inherent (far-field) hydraulic heads in each of the conductive features. The multirate method was successfully applied to a 500-m borehole in a granitic formation and reported recently. The present paper describes the application of the method to two zones within a 1000-m borehole in sedimentary rock, which produced, for each zone, three sets of logs at different pumping rates, each set measured over a period of about 1 day. The data sets involve several complications, such as variable well diameter, gradual water level decline in the well during logging, possible Fluid flow through the unfractured rock matrix, and effects of drilling mud. Various techniques were applied to analyze the FFEC logs: direct-fitting, mass integral, and the multirate method mentioned above. In spite of complications associated with the tests, analysis was able to identify 44 hydraulically conducting fractures distributed over the depth interval 150–775 m below ground surface. The salinities (in FEC), and transmissivities and hydraulic heads (in dimensionless form) of these 44 features were obtained and found to vary significantly among one another. These results were compared with transmissivity and head values inferred from eight packer tests that were conducted in this borehole over the same depth interval. FFEC results were found to be consistent with packer test results, thus demonstrating the robustness of the FFEC logging method under nonideal conditions.
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Application of direct-fitting, mass-integral, and multi-rate methods to analysis of Flowing Fluid electric conductivity logs from Horonobe, Japan
Lawrence Berkeley National Laboratory, 2008Co-Authors: Christine Doughty, Chin-fu Tsang, Koichiro Hatanaka, S. Yabuuchi, Hiroshi KurikamiAbstract:The Flowing Fluid electric conductivity (FFEC) logging method is an efficient way to provide information on the depths, salinities, and transmissivities of individual conductive features intercepted by a borehole, without the use of specialized probes. Using it in a multiple-flow-rate mode allows, in addition, an estimate of the inherent far-field pressure heads in each of the conductive features. The multi-rate method was successfully applied to a 500-m borehole in a granitic formation and reported recently. The present paper presents the application of the method to two zones within a 1000-m borehole in sedimentary rock, which produced, for each zone, three sets of logs at different pumping rates, each set measured over a period of about one day. The data sets involve a number of complications, such as variable well diameter, free water table decline in the well, and effects of drilling mud. To analyze data from this borehole, we apply various techniques that have been developed for analyzing FFEC logs: direct-fitting, mass-integral, and the multi-rate method mentioned above. In spite of complications associated with the tests, analysis of the data is able to identify 44 hydraulically conducting fractures distributed over the depth interval 150-775 meters below ground surface. The salinities (in FEC), and transmissivities and pressure heads (in dimensionless form) of these 44 features are obtained and found to vary significantly among one another. These results are compared with data from eight packer tests with packer intervals of 10-80 m, which were conducted in this borehole over the same depth interval. They are found to be consistent with these independent packer-test data, thus demonstrating the robustness of the FFEC logging method under non-ideal conditions.