scholarly journals Numerical Simulations of Heterogeneous Chemical Reactions Coupled to Fluid Flow in Varying Thermal Fields

1991 ◽  
Vol 257 ◽  
Author(s):  
C. L. Carnahan
Keyword(s):  
Fluid Flow ◽  
Silicic Acid ◽  
Calcium Ion ◽  
Acid System ◽  
Thermal Fields ◽  
Transient Heat Flow ◽  
Porosity And Permeability ◽  
Strong Gradient ◽  
Reactive Chemical Transport ◽  
Heterogeneous Chemical Reactions

ABSTRACTA numerical simulator of reactive chemical transport with coupling from precipitation-dissolution reactions to fluid flow, via changes of porosity and permeability, is applied to precipitation-dissolution of quartz and calcite in spatially and temporally variable fields of temperature. Significant effects on fluid flow are found in the quartz-silicic acid system in the presence of a persistent, strong gradient of temperature. Transient heat flow in the quartz-silicic acid system and in a calcite-calcium ion-carbonato species system produces vanishingly small effects on fluid flow.

scholarly journals Geostatistical Model for the Arab-D Reservoir, North ’Ain Dar Pilot, Ghawar Field, Saudi Arabia: An Improved Reservoir Simulation Model

GeoArabia ◽  
1996 ◽  
Vol 1 (2) ◽  
pp. 267-284
Author(s):  
John L. Douglas ◽  
Keyword(s):  
Saudi Arabia ◽  
Fluid Flow ◽  
Reservoir Rock ◽  
Well Test ◽  
Geostatistical Model ◽  
Deterministic Models ◽  
Modeling Approach ◽  
The North ◽  
Porosity And Permeability ◽  
Ghawar Field

ABSTRACT The North ‘Ain Dar 3-D geocellular model consists of geostatistical models for electrofacies, porosity and permeability for a portion of the Jurassic Arab-D reservoir of Ghawar field, Saudi Arabia. The reservoir consists of a series of shallow water carbonate shelf sediments and is subdivided into 10 time-stratigraphic slices on the basis of core descriptions and gamma/porosity log correlations. The North ‘Ain Dar model includes an electrofacies model and electrofacies-dependent porosity and permeability models. Sequential Indicator Simulations were used to create the electrofacies and porosity models. Cloud Transform Simulations were used to generate permeability models. Advantages of the geostatistical modeling approach used here include: (1) porosity and permeability models are constrained by the electrofacies model, i.e. by the distribution of reservoir rock types; (2) patterns of spatial correlation and variability present in well log and core data are built into the models; (3) data extremes are preserved and are incorporated into the model. These are critical when it comes to determining fluid flow patterns in the reservoir. Comparison of model Kh with production data Kh indicates that the stratigraphic boundaries used in the model generally coincide with shifts in fluid flow as indicated by flowmeter data, and therefore represent reasonable flow unit boundaries. Further, model permeability and production estimated permeability are correlated on a Kh basis, in terms of vertical patterns of distribution and cumulative Kh values at well locations. This agreement between model and well test Kh improves on previous, deterministic models of the Arab-D reservoir and indicates that the modeling approach used in North ‘Ain Dar should be applicable to other portions of the Ghawar reservoir.

Evaluation of a New Automatic Calcium Ion Analyzer

1977 ◽  
Vol 23 (4) ◽  
pp. 690-694 ◽  
Author(s):  
SØren Madsen ◽  
Klaus ⵁlgaard
Keyword(s):  
Fluid Flow ◽  
Ionic Strength ◽  
Calcium Ion ◽  
Calcium Binding ◽  
Routine Laboratory ◽  
Mean Values ◽  
Binding Effect ◽  
Physiological Range ◽  
Flow Through ◽  
First Time

Abstract We evaluated a new automatic analyzer for ionized cal¬cium (Ca2+), the Orion Model SS-20, based on a flow-through ion-exchange electrode. Ca2+ was measured in heparinized whole blood and serum. Within-day variation was 1.2%, day-to-day variation 1.6 %, and analytical re-covery 92.4%. Over the physiological range interference by K± and Mg2+ was negligible; major changes in ionic strength, induced by changes in Na+ concentration, made correction for a sodium error necessary. Within the physiological range, Ca2+ was inversely correlated to variations in pH. Therefore, to compare Ca2+ values, correction to an apparent pH of 7.40 should be made. The calcium binding effect of heparin was negligible when minimal (4.4 int. units/m1) concentrations of heparin were used. Storage of serum at 4 °C for one week resulted in a 4% decrease in apparent serum Ca2+, primarily owing to an increase in pH during storage. In normal material, mean values for blood- and serum-Ca2+ (1.10 and 1.07 mmol/liter, respectively) were close to results obtained by previous systems. Errors caused by disturbances in the fluid flow and non-function of half the electrodes we re¬ceived were the major inconveniences of the analyzer. We conclude that this new analyzer gives decisive advantages in measurement of Ca2+, making this important analysis possible as a routine laboratory test for the first time

The Effect of the Dust Cake Resistance on Fluid Flow Passing through the Filter Media

2012 ◽  
Vol 727-728 ◽  
pp. 758-763 ◽  
Author(s):  
Sandra Mara Santana Rocha ◽  
M.S. Bacelos ◽  
João Jorge Ribeiro Damasceno ◽  
L.G.M. Vieira ◽  
M.L. Aguiar
Keyword(s):  
Experimental Data ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Filter Media ◽  
Air Velocity ◽  
Cfd Simulations ◽  
Porosity And Permeability ◽  
Cake Porosity

A filter box was used to obtain the experimental data of filtration operation with different air velocities as 5, 10 and 15 cm/s. The experimental data were compared to the simulated ones using CFD technique. For all range of air velocity and dust cake porosity and permeability employed, data of pressure drop in filter box could be satisfactorily predicted by simulations in CFD. Furthermore, the CFD simulations showed that undesirable patchy cleaning might be overcome using air velocities lower than 15cm/s.

scholarly journals Transient conduit permeability controlled by a shift between compactant shear and dilatant rupture at Unzen volcano (Japan)

2021 ◽  
Author(s):  
Yan Lavallée ◽  
Takahiro Miwa ◽  
James D. Ashworth ◽  
Paul A. Wallace ◽  
Jackie E. Kendrick ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Shear Zone ◽  
Damage Zone ◽  
Volcanic Eruptions ◽  
Shear Zones ◽  
Stick Slip ◽  
Anisotropic Permeability ◽  
Unzen Volcano ◽  
Porosity And Permeability ◽  
Low Porosity

Abstract. The permeability of magma in shallow volcanic conduits controls the fluid flow and pore pressure development that regulates gas emissions and the style of volcanic eruptions. The architecture of the permeable porous structure is subject to changes as magma deforms and outgasses during ascent. Here, we present a high-resolution study of the permeability distribution across two conduit shear zones (marginal and central) developed in the dacitic spine that extruded towards the closing stages of the 1991–1995 eruption at Unzen volcano, Japan. The marginal shear zone is approximately 3.2 m wide and exhibits a 2-m wide, moderate shear zone with porosity and permeability similar to the conduit core, transitioning into a ~1-m wide, highly-sheared region with relatively low porosity and permeability, and an outer 20-cm wide cataclastic fault zone. The low porosity, highly-sheared rock further exhibits an anisotropic permeability network with slightly higher permeability along the shear plane (parallel to the conduit margin) and is locally overprinted by oblique dilational Riedel fractures. The central shear zone is defined by a 3-m long by ~9-cm wide fracture ending bluntly and bordered by a 15–40 cm wide damage zone with an increased permeability of ~3 orders of magnitude; directional permeability and resultant anisotropy could not be measured from this exposure. We interpret the permeability and porosity of the marginal shear zone to reflect the evolution of compactional (i.e., ductile) shear during ascent up to the point of rupture, estimated by Umakoshi et al. (2008), at ~500 m depth. At this point the compactional shear zone would have been locally overprinted by brittle rupture, promoting the development of a shear fault and dilational Riedel fractures during repeating phases of increased magma ascent rate, enhancing anisotropic permeability that channels fluid flow into, and along, the conduit margin. In contrast, we interpret the central shear zone as a shallow, late-stage dilational structure, which partially tore the spine core with slight displacement. We explore constraints from monitored seismicity and stick-slip behaviour to evaluate the rheological controls, which accompanied the upward shift from compactional toward dilational shear as magma approached the surface, and discuss their importance in controlling the permeability development of magma evolving from overall ductile to increasingly brittle behaviour during ascent and eruption.

scholarly journals Structural control on fluid flow and shallow diagenesis: insights from calcite cementation along deformation bands in porous sandstones

Solid Earth ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 2169-2195
Author(s):  
Leonardo Del Sole ◽  
Marco Antonellini ◽  
Roger Soliva ◽  
Gregory Ballas ◽  
Fabrizio Balsamo ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Structural Control ◽  
Control Flow ◽  
Porous Rocks ◽  
Deformation Bands ◽  
Seismic Resolution ◽  
Porous Sandstone ◽  
Reservoir Compartmentalization ◽  
Porosity And Permeability ◽  
And Control

Abstract. Porous sandstones are important reservoirs for geofluids. Interaction therein between deformation and cementation during diagenesis is critical since both processes can strongly reduce rock porosity and permeability, deteriorating reservoir quality. Deformation bands and fault-related diagenetic bodies, here called “structural and diagenetic heterogeneities”, affect fluid flow at a range of scales and potentially lead to reservoir compartmentalization, influencing flow buffering and sealing during the production of geofluids. We present two field-based studies from Loiano (northern Apennines, Italy) and Bollène (Provence, France) that elucidate the structural control exerted by deformation bands on fluid flow and diagenesis recorded by calcite nodules associated with the bands. We relied on careful in situ observations through geo-photography, string mapping, and unmanned aerial vehicle (UAV) photography integrated with optical, scanning electron and cathodoluminescence microscopy, and stable isotope (δ13C and δ18O) analysis of nodules cement. In both case studies, one or more sets of deformation bands precede and control selective cement precipitation. Cement texture, cathodoluminescence patterns, and their isotopic composition suggest precipitation from meteoric fluids. In Loiano, deformation bands acted as low-permeability baffles to fluid flow and promoted selective cement precipitation. In Bollène, clusters of deformation bands restricted fluid flow and focused diagenesis to parallel-to-band compartments. Our work shows that deformation bands control flow patterns within a porous sandstone reservoir and this, in turn, affects how diagenetic heterogeneities are distributed within the porous rocks. This information is invaluable to assess the uncertainties in reservoir petrophysical properties, especially where structural and diagenetic heterogeneities are below seismic resolution.

Numerical Flow Visualization and Thermal Transport Phenomena Over a Slot-Perforated Flat Surface in Pulsating Channel Flow

2002 ◽  
Author(s):  
Shuichi Torii ◽  
Wen-Jei Yang
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Channel Flow ◽  
Heat Transfer Performance ◽  
Theoretical Study ◽  
Flat Surface ◽  
Plate Thickness ◽  
Transfer Performance ◽  
Thermal Fields ◽  
Thermal Fluid Flow

A theoretical study is performed to investigate unsteady, two-dimensional, incompressible thermal-fluid flow over both sides of a slot-perforated flat surface, which is placed in a pulsating channel flow. The roles of both the pulsating Strouhal number and the ratio of the channel width to the plate thickness, W/δ, on the velocity and thermal fields are disclosed. It is found from the study that: (i) when the channel stream is pulsated, the alternating change in the fluid flow disturbs the thermal boundary layer formed along the plate and induces mixing of the upper and lower streams of the plate downstream from the slot, resulting in an amplification of heat transfer performance, and (ii) heat transfer performance at the plate is attenuated with a decrease in W/δ.

Heat Transfer Mode and Effect of Fluid Flow on the Morphology of the Weld Pool

2021 ◽  
Vol 406 ◽  
pp. 66-77
Author(s):  
Abdel Halim Zitouni ◽  
Pierre Spiteri ◽  
Mouloud Aissani ◽  
Younes Benkheda
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Weld Pool ◽  
Stokes Equations ◽  
Solid Phase ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Transfer Mode ◽  
Thermal Fields ◽  
Welding Properties

In this work, the heat transfer by conduction and convection mode and effect of fluid flow on the morphology of the weld pool and the welding properties is investigated during Tungsten Inert Gas (TIG) process. In the first part, a computation code under Fortran was elaborated to solve the equations resulting from the finite difference discretization of the heat equation, taking into account the liquid-solid phase change with the associated boundary conditions. In order to calculate the velocity field during welding, the Navier-Stokes equations in the melt zone were simplified and solved considering their stream-vorticity formulation. A mathematical model was developed to study the effect of the melted liquid movement on the weld pool. The evolution of the fraction volume of the liquid and the thermal fields promoted the determination of the molten zone (MZ) and the Heat Affected Zone (HAT) dimensions, which seems to be in good agreement with literature.

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