scholarly journals Effects of fluid influx, fluid viscosity, and fluid density on fluid migration in the mantle wedge and their implications for hydrous melting

Geosphere ◽  
2018 ◽  
Vol 15 (1) ◽  
pp. 1-23 ◽  
Author(s):  
Nestor G. Cerpa ◽  
Ikuko Wada ◽  
Cian R. Wilson
Keyword(s):  
Mantle Wedge ◽  
Fluid Migration ◽  
Fluid Viscosity ◽  
Fluid Density ◽  
Hydrous Melting

Fluid influence on the trace element compositions of subduction zone magmas

1991 ◽  
Vol 335 (1638) ◽  
pp. 377-392 ◽  
Keyword(s):  
Subduction Zones ◽  
Mantle Wedge ◽  
Chemical Fractionation ◽  
Ocean Island Basalts ◽  
Hydrous Melting ◽  
Dehydration Processes ◽  
Slab Dehydration ◽  
Subduction Magmatism ◽  
Element Flux ◽  
Continental Growth

Subduction zones represent major sites of chemical fractionation within the Earth. Element pairs which behave coherently during normal mantle melting may become strongly decoupled from one another during the slab dehydration processes and during hydrous melting conditions in the slab and in the mantle wedge. This results in the large ion lithophile elements (e.g. K, Rb, Th, U, Ba) and the light rare earth elements being transferred from the slab to the mantle wedge, and being concentrated within the mantle wedge by hydrous fluids, stabilized in hydrous phases such as hornblende and phlogopite, from where they are eventually extracted as magmas and contribute to growth of the continental crust. High-field strength elements (e.g. Nb, Ta, Ti, P, Zr) are insoluble in hydrous fluids and relatively insoluble in hydrous melts, and remain in the subducted slab and the adjacent parts of the mantle which are dragged down and contribute to the source for ocean island basalts. The required element fractionations result from interaction between specific mineral phases (hornblende, phlogopite, rutile, sphene, etc.) and hydrous fluids. In present day subduction magmatism the mantle wedge contributes dominantly to the chemical budget, and there is a requirement for significant convection to maintain the element flux. In the Precambrian, melting of subducted ocean crust may have been easier, providing an enhanced slab contribution to continental growth.

Fluid migration in the mantle wedge: Influence of mineral grain size and mantle compaction

2017 ◽  
Vol 122 (8) ◽  
pp. 6247-6268 ◽  
Author(s):  
Nestor G. Cerpa ◽  
Ikuko Wada ◽  
Cian R. Wilson
Keyword(s):  
Grain Size ◽  
Mantle Wedge ◽  
Fluid Migration

scholarly journals Effect of molten salt properties on internal flow and disk friction loss of molten salt pump

2020 ◽  
Vol 24 (4) ◽  
pp. 2347-2356
Author(s):  
Yong-Xin Jin ◽  
De-Sheng Zhang ◽  
Xi Sheng ◽  
Lei Shi ◽  
Wei-Dong Shi ◽  
...  
Keyword(s):  
Shear Stress ◽  
Molten Salt ◽  
Pure Water ◽  
Friction Loss ◽  
Effect Of Temperature ◽  
Fluid Viscosity ◽  
Fluid Density ◽  
Working Fluids ◽  
Pump Performance ◽  
Disk Friction

Computational fluid dynamics is used to study the effect of temperature on flow structure and disk friction loss for different working fluids in a high temperature molten salt pump, which is used for concentrating solar power, the velocity profile and pressure distribution in the first stage of the pump model and the effect of the fluid property on the ring leakage, disk friction loss as well as the shear stress distribution on shroud are analyzed for the pure water and the molten salt with temperature 300?C and 565?C respectively. The main findings can be concluded as: the working fluids have little effect on pump performance and internal velocity distribution whereas the pressure of the flow field would increase with the fluid density, with the increase of the fluid viscosity, the shear stress inside the ring also increases and the total leakage can be eliminated evidently, the increase of the fluid density and viscosity show the significant responsibility for the disk friction loss, in which the fluid viscosity also increases the disk friction loss, and the viscosity is one of the most influential factors for the shroud shear stress and it can be observed that the shear stress on front shroud is higher than that on the rear shroud. It is believed that the present work can deep the understandings of the fluid structures inside the molten salt pump, which can provide some guidelines to improve the pump performance and optimize the pump structure.

Pulse Decay Permeability: Analytical Solution and Experimental Test

1982 ◽  
Vol 22 (05) ◽  
pp. 719-721 ◽  
Author(s):  
Thierry Bourbie ◽  
Joel Walls
Keyword(s):  
Analytical Solution ◽  
Pore Pressure ◽  
Pressure Pulse ◽  
Numerical Solutions ◽  
Core Sample ◽  
Pore Fluid ◽  
Differential Pressure ◽  
Fluid Viscosity ◽  
Fluid Density ◽  
Permeability Problem

Abstract A new analytical solution is presented for the laboratory pulse decay permeability problem. With this solution, pulse decay permeability problem. With this solution, permeability of a core sample can be calculated from the permeability of a core sample can be calculated from the decay rate of a pressure pulse applied to one end of the sample. This development permits rapid. accurate measurement of permeability in samples such as tight gas sands, limestones, and shales. Introduction Because of its usefulness in measuring very low permeability. the pulse decay technique has been permeability. the pulse decay technique has been discussed often in the literature. In this technique, a small pore pressure pulse is applied to one end of a jacketed sample, and the pressure vs. time behavior is observed as the pore fluid moves through the sample from one reservoir to another. Brace et al. cave an approximate solution to this problem with the assumption of a linear pressure gradient at all times. This simplification leads to a predicted exponential pressure vs. time decay. By means of numerical solutions, Lin and Yamada and Jones have shown that the Brace solution can lead to significant errors in calculating permeability. These numerical solutions. however. are inconvenient to use and require considerable computer programming time. We present an analytical solution based on realistic assumptions and boundary conditions. Experimental Technique To understand the theoretical problem more thoroughly, a short description of the experiment is desirable. Fig. 1 is a schematic of the system. Initially, both valves are open and pressure is constant throughout the system. Next, Valve 1 is closed, and the pressure is changed slightly in the large Reservoir 1. Valve 1 remains closed for a few minutes to allow thermal effects to diminish (particularly important if the pore fluid is (as). Valve 2 then is closed, and, at time equal zero. Valve 1 is opened. A small differential pressure between the reservoirs will be indicated by the p transducer and will decrease with time. Pressure in Reservoir 1 remains constant during the decay. After the differential pressure has decreased by approximately 20%, Valve 2 is opened to terminate the decay. This accelerates the equilibration of pressure so that the next measurement can be made. pressure so that the next measurement can be made. Theory As stated earlier, the pressure in Reservoir 1 remains essentially constant during the decay (t 0) because the volume of Reservoir 1, V1, is much greater than the pore volume, Vp, or the volume of Reservoir 2, V2. It can be assumed that fluid viscosity, is independent of position, x, in the sample and that fluid density, p, position, x, in the sample and that fluid density, p, permeability, k, and porosity, are dependent only on permeability, k, and porosity, are dependent only on fluid pressure, P. By combining Darcy's law with the one-dimensional diffusion equation we obtain ,..................(1) where B is fluid compressibility, Bs, is rock compressibility, and Bk is the dependence of permeability on pore pressure. The magnitude of the nonlinear terms pore pressure. The magnitude of the nonlinear terms with respect to the linear ones is equal to (Bk + B)P0, where P0 is the pressure pulse amplitude. Because (Bk - B ) = 10 -2 bar - 1 (Ref. 8) and P0=1 bar, the product is small, and, hence, nonlinear terms can be product is small, and, hence, nonlinear terms can be ignored. If we further assume that the equation of flow is ------- = --- --------, ......................(2) SPEJ P. 719

On the formation of bubbles in gas-particulate fluidized beds

1979 ◽  
Vol 94 (2) ◽  
pp. 353-367 ◽  
Author(s):  
Jerome B. Fanucci ◽  
Nathan Ness ◽  
Ruey-Hor Yen
Keyword(s):  
Fluidized Beds ◽  
Method Of Characteristics ◽  
Bubble Formation ◽  
Shock Formation ◽  
Fluid Viscosity ◽  
Phase Flow ◽  
Fluid Density ◽  
Pressure Function ◽  
Two Phase ◽  
Particulate Size

The method of characteristics is applied to the nonlinear equations describing two-phase flow in a fluidized bed. The method shows how a small disturbance changes with time and distance and can, eventually, produce a flow discontinuity similar to a shock wave in gases. The parameters entering the analysis are the amplitude of the initial disturbance, the wavelength of the original disturbance, the particulate pressure function, the particulate size, the uniform fluidization voidage, the uniform fluidization velocity, the fluid viscosity, the particulate density, and the fluid density. A parametric study shows that the following factors delay shock formation: a decrease in particulate size, an increase in bed density, an increase in fluid viscosity, and a decrease in particulate density. Experimental data on bubble formation in gas-particulate fluidized beds show that these same factors delay bubble formation. It is concluded, therefore, that the shock front and the bubble front are one and the same thing.

Uncertainties in the stability field of UHP hydrous phases (10-A phase and phase E) and deep-slab dehydration: potential implications for fluid migration and water fluxes at subduction zones

2020 ◽  
Author(s):  
Nestor G. Cerpa ◽  
José Alberto Padrón-Navarta ◽  
Diane Arcay
Keyword(s):  
Lithospheric Mantle ◽  
Subduction Zones ◽  
Mantle Wedge ◽  
Numerical Models ◽  
Stability Field ◽  
Fluid Migration ◽  
Water Fluxes ◽  
Water Release ◽  
The Stability ◽  
Back Arc

<p>The subduction of water via lithospheric-mantle hydrous phases have major implications for the generation of arc and back-arc volcanism, as well as for the global water cycle. Most of the current numerical models use Perple_X [Connolly et al., 2009] to quantify water release from the slab and subsequent fluid migration in the mantle wedge. At UHP conditions, the phase diagrams generated with this thermodynamic code suggest that the breakdown of serpentine and chlorite leads to the near complete dehydration of the lithospheric mantle before reaching a 200-km depth. Laboratory experiments, however, have observed the stability of the 10-Å phase and the phase E in natural bulk compositions, which may hold moderate amounts of water, beyond the stability field of serpentine and chlorite [Fumagalli and Poli, 2005; Maurice et al., 2018]. Here, using 2D thermo-mechanical models, we explore to what extent the presence of these hydrous phases may favor a deeper subduction of water than those predicted by Perple_X.</p><p>We perform end-member models in terms of slab temperature and thickness of hydrated lithospheric mantle entering at trench. The computed geotherms within the uppermost subducted mantle show that the stability field of mantle hydrous phases around 600-800°C and 6-8 GPa is crucial for predictions of water fluxes. We point out that the lack of systematic experiments at these P-T conditions, as well as the absence of 10-Å and E phases in current thermodynamic databases, prevent accurate estimates of deep water transfers. We nonetheless build a phase diagram based on current experimental constraints that includes approximations of their stability field and qualitatively discuss the potential implications for fluid migration in the back-arc mantle wedge and water fluxes.</p>

scholarly journals Magnesium isotope geochemistry in arc volcanism

2016 ◽  
Vol 113 (26) ◽  
pp. 7082-7087 ◽  
Author(s):  
Fang-Zhen Teng ◽  
Yan Hu ◽  
Catherine Chauvel
Keyword(s):  
Mantle Wedge ◽  
Narrow Range ◽  
Isotope Geochemistry ◽  
Isotopic Signature ◽  
Fluid Migration ◽  
Arc Volcanism ◽  
Mg Isotopes ◽  
Deep Fluid ◽  
Isotopic Variations ◽  
Subducting Slab

Incorporation of subducted slab in arc volcanism plays an important role in producing the geochemical and isotopic variations in arc lavas. The mechanism and process by which the slab materials are incorporated, however, are still uncertain. Here, we report, to our knowledge, the first set of Mg isotopic data for a suite of arc lava samples from Martinique Island in the Lesser Antilles arc, which displays one of the most extreme geochemical and isotopic ranges, although the origin of this variability is still highly debated. We find the δ26Mg of the Martinique Island lavas varies from −0.25 to −0.10, in contrast to the narrow range that characterizes the mantle (−0.25 ± 0.04, 2 SD). These high δ26Mg values suggest the incorporation of isotopically heavy Mg from the subducted slab. The large contrast in MgO content between peridotite, basalt, and sediment makes direct mixing between sediment and peridotite, or assimilation by arc crust sediment, unlikely to be the main mechanism to modify Mg isotopes. Instead, the heavy Mg isotopic signature of the Martinique arc lavas requires that the overall composition of the mantle wedge is buffered and modified by the preferential addition of heavy Mg isotopes from fluids released from the altered subducted slab during fluid−mantle interaction. This, in turn, suggests transfer of a large amount of fluid-mobile elements from the subducting slab to the mantle wedge and makes Mg isotopes an excellent tracer of deep fluid migration.

The Effects of Fluid Viscosity and Density on Proppant Transport in Complex Slot Systems

2021 ◽  
Author(s):  
Ashtiwi Bahri ◽  
Jennifer Miskimins
Keyword(s):  
Sodium Chloride ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Positive Impact ◽  
Fluid Viscosity ◽  
Fluid Density ◽  
Fracture Conductivity ◽  
Proppant Transport ◽  
Glycerin Solution ◽  
Injection Rates

Abstract The main functions of hydraulic fracturing fluids are to create a fracture network and to carry and place the proppant into the created fractures networks, thus, adding to fracture conductivity. Significant research has been performed to develop ideal fracturing fluid systems. The development focus has mainly been on optimization of a fluid rheology that can transport and place the proppant into the primary and any subsidiary fractures with less damage to the formation and at a lower cost. The main goal of this work is to add to the understanding and optimization of proppant transport in complex hydraulic fracture networks. Specifically for this study, focus is placed on two different fluids, water-glycerin solution and water-sodium chloride solution, representing varying fluid densities and viscosities. The effects of changing fluid viscosities, densities, proppant densities, proppant sizes, proppant concentrations, and slurry injection rates on proppant transport were then experimentally investigated. This experimental work shows that viscosity has a greater impact on the proppant transport than fluid density does, thus implying a larger impact on the resulting fracture conductivity. The results of this work show that a water-glycerin solution, with a viscosity of 4.3 cp, has significant proppant carrying capacity with proppants delivered uniformly to greater distances. On the other hand, the results show that a water-sodium chloride solution of 9.24 ppg density has less capability to carry the proppant deep into the fractures indicating that viscosity has a greater impact on the proppant transport than fluid density does. The lab results also showed that increasing proppant concentrations and injection rates has a positive impact on proppant transport.

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