Imaging the Architecture of Mineral Systems and the Pathways of Ore-forming Fluids across Mongolia with Magnetotellurics

In the framework of a mineral system approach,a combination of components is required to develop a mineral system.This includes the whole-lithosphere architecture,which controls the transport of ore-forming fluids,and favorable tectonic and geodynamic processes,occurring at various spatial and temporal scales,that influence the genesis and evolution of ore-forming fluids(Huston et al.,2016;Groves et al.,2018;Davies et al.,2020).Knowledge of the deep structural framework can advance the understanding of the development of a mineral system and the emplacement of mineral deposits.Deep geophysical exploration carried out with this aim is increasingly important for targeting new ore deposits in unexplored and underexplored regions(Dentith et al.,2018;Dentith,2019).

A two-phase type-curve method with multiscale fluid transport mechanisms in hydraulically fractured shale reservoirs

The quantitative understanding of hydraulic fracture(HF)properties guides accurate production forecasts and reserve estimation.Type curve is a powerful technique to characterize HF and reservoir properties from flowback and long-term production data.However,two-phase flow of water and hydrocarbon after an HF stimulation together with the complex transport mechanisms in shale nanopores exacerbate the nonlinearity of the transport equation,causing errors in type-curve analysis.Accordingly,we propose a new two-phase type-curve method to estimate HF properties,such as HF volume and permeability of fracture,through the analysis of flowback data of multi-fractured shale wells.The proposed type curve is based on a semianalytical solution that couples the two-phase flow from the matrix with the flow in HF by incorporating matrix influx,slippage effect,stress dependence,and the spatial variation of fluid properties in inorganic and organic pores.For the first time,multiple fluid transport mechanisms are considered into two-phase type-curve analysis for shale reservoirs.We analyze the flowback data from a multi-fractured horizontal well in a shale gas reservoir to verify the field application of the proposed method.The results show that the fracture properties calculated by the type-curve method are in good agreement with the long-time production data.

Investigating the Whole-lithosphere Structure of a Mineral System——Pathways and Source of Ore-forming Fluids Imaged with Magnetotelluric Modeling

Whole-lithosphere structure has direct implications for both the genesis of minerals and the locations of mineral emplacement;thus knowledge of the deep structural framework of the lithosphere can advance understanding of the development and evolution of mineral systems.

A Bingham-Plastic Model for Fluid Mud Transport Under Waves and Currents

Simplified equations of fluid mud motion, which is described as Bingham-Plastic model under waves and currents, are presented by order analysis. The simplified equations are non-linear ordinary differential equations which are solved by hybrid numerical-analytical technique. As the computational cost is very low, the effects of wave current parameters and fluid mud properties on the transportation velocity of the fluid mud are studied systematically. It is found that the fluid mud can move toward one direction even if the shear stress acting on the fluid mud bed is much smaller than the fluid mud yield stress under the condition of wave and current coexistence. Experiments of the fluid mud motion under current with fluctuation water surface are carried out. The fluid mud transportation velocity predicted by the presented mathematical model can roughly match that measured in experiments.

A multiscale 3D finite element analysis of fluid/solute transport in mechanically loaded bone

The transport of fluid, nutrients, and signaling molecules in the bone lacunar-canalicular system （LCS） is critical for osteocyte survival and function. We have applied the fluorescence recovery after photobleaching （FRAP） approach to quantify load-induced fluid and solute transport in the LCS in situ, but the measurements were limited to cortical regions 30-50 μm underneath the periosteum due to the constrains of laser penetration. With this work, we aimed to expand our understanding of load-induced fluid and solute transport in both trabecular and cortical bone using a multiscaled image-based finite element analysis （FEA） approach. An intact murine tibia was first re-constructed from microCT images into a three-dimensional （3D） linear elastic FEA model, and the matrix deformations at various locations were calculated under axial loading. A segment of the above 3D model was then imported to the biphasic poroelasticity analysis platform （FEBio） to predict load-induced fluid pressure fields, and interstitial solute/fluid flows through LCS in both cortical and trabecular regions. Further, secondary flow effects such as the shear stress and/or drag force acting on osteocytes, the presumed mechano-sensors in bone, were derived using the previously developed ultrastructural model of Brinkman flow in the canaliculi. The material properties assumed in the FEA models were validated against previously obtained strain and FRAP transport data measured on the cortical cortex. Our results demonstrated the feasibility of this computational approach in estimating the fluid flux in the LCS and the cellular stimulation forces （shear and drag forces） for osteocytes in any cortical and trabecular bone locations, allowing further studies of how the activation of osteocytes correlates with in vivo functional bone formation. The study provides a promising platform to reveal potential cellular mechanisms underlying the anabolic power of exercises and physical activities in treating patients with skeletal deficiencies.

Dynamic fluid transport property of hydraulic fractures and its evaluation using acoustic logging

The existing acoustic logging methods for evaluating the hydraulic fracturing effectiveness usually use the fracture density to evaluate the fracture volume, and the results often cannot accurately reflect the actual productivity. This paper studies the dynamic fluid flow through hydraulic fractures and its effect on borehole acoustic waves. Firstly, based on the fractal characteristics of fractures observed in hydraulic fracturing experiments, a permeability model of complex fracture network is established. Combining the dynamic fluid flow response of the model with the Biot-Rosenbaum theory that describes the acoustic wave propagation in permeable formations, the influence of hydraulic fractures on the velocity dispersion of borehole Stoneley-wave is then calculated and analyzed, whereby a novel hydraulic fracture fluid transport property evaluation method is proposed. The results show that the Stoneley-wave velocity dispersion characteristics caused by complex fractures can be equivalent to those of the plane fracture model, provided that the average permeability of the complex fracture model is equal to the permeability of the plane fracture. In addition, for fractures under high-permeability(fracture width 10~100 μm, permeability ~100 μm^(2)) and reduced permeability(1~10 μm, ~10 μm^(2), as in fracture closure) conditions, the Stoneley-wave velocity dispersion characteristics are significantly different. The field application shows that this fluid transport property evaluation method is practical to assess the permeability and the connectivity of hydraulic fractures.

Numerical simulation on inclusion transport in continuous casting mold

Turbulent flow, the transpor＇t of inclusions and bubbles, and inclusion removal by fluid flow, transport and by bubble flotation in the strand of the continuous slab caster are investigated using computational models, and validated through comparison with plant measurements of inclusions. Steady 3-D flow of steel in the liquid pool in the mold and upper strand is simulated with a finitedifference computational model using the standard k-εturbulence rondel. Trajectories of inclusions and bubhles tire calculated by integrating each local velocity, considering its drag and buoyancy forces, A ＂random walk＂ model is used to incorporate the effect of turbulent fluctuations on the particle motion. The attachment probability of inclusions on a bubble surface is investigated based on fundamental fluid flow simulations, incorporating the turbulent inclusion trajectory and sliding time of each individual inclusion along the bubble surface as a function of particle and bubble size. The chunge in inclusion distribution due to removal by bubble transport in the mold is calculated based on the computed attachment probability of inclusions on each bubble and the computed path length of the bubbles. The results indicate that 6%-10% inclusions are removed by fluid flow transport. 10% by bubble flotation, and 4% by entrapment to the submerged entry nozzle （SEN） walls. Smaller bubbles and larger inclusions have larger attachment probabilities. Smaller bubbles are more efficient for inclusion removal by bubble flotation, so Inng as they are not entrapped in the solidifying shell A larger gas flow rate favors inclusion removal by bubble flotation. The optimum bubble size should be 2-4mm.

Numerical modelling of flow and transport in rough fractures

Simulation of flow and transport through rough walled rock fractures is investigated using the latticeBoltzmann method （LBM） and random walk （RW）, respectively. The numerical implementation isdeveloped and validated on general purpose graphic processing units （GPGPUs）. Both the LBM and RWmethod are well suited to parallel implementation on GPGPUs because they require only next-neighbourcommunication and thus can reduce expenses. The LBM model is an order of magnitude faster onGPGPUs than published results for LBM simulations run on modern CPUs. The fluid model is verified forparallel plate flow, backward facing step and single fracture flow; and the RWmodel is verified for pointsourcediffusion, Taylor-Aris dispersion and breakthrough behaviour in a single fracture. Both algorithmsplace limitations on the discrete displacement of fluid or particle transport per time step to minimise thenumerical error that must be considered during implementation. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.

CFD modeling of a headbox with injecting dilution water in a central step diffusion tube

For engineering applications of water dilution controlling system,the fluid dynamics of a mixed flow was studied with computational fluid dynamics(CFD) simulations and self-designed experimental set-up.In order to examine the predictability of CFD model for the headbox in industrial scale,two pulp suspensions before mixing were treated as homogeneous flows separately.Standard k-ε turbulence models with the mass diffusion in turbulent flows-species transport approach were applied in the simulations.A numerical simulation of this headbox model was analyzed with semi-implicit method for pressure linked equations scheme with pressure–velocity coupling.Results show that the model can predict hydrodynamic characteristics of headbox with injecting dilution water in a central diffusion tube,and the distribution of water content at the outlet of the slice lip is ideally normal at different speeds.

Coupled tripartite investigation of breaker fluid invasion and impact on hydrocarbon recovery in sandstone reservoirs

Breaker fluids are designed to dissolve filter cakes by breaking their long-chain molecules,thereby removing solid deposits on the wellbore wall.Although breaker fluids are not intended to infiltrate the hydrocarbon reservoir,they can invade and cause formation damage by altering sandstone reservoirs'wettability and relative permeability.This can lead to a reduction in the overall reservoir performance.This study coupled tripartite methods to investigate the potential impact of breaker invasion and transport in hydrocarbon reservoirs and its multiscale effect on the performances of sandstone reservoirs.We utilized experimental,analytical,and numerical methods to assess and predict the susceptibility of reservoirs to breaker fluid invasion and transportation.Our experimental and empirical investigations considered varying breaker fluid formulations to evaluate the effects of breaker fluid concentration,formation temperature,and solution gas-oil ratio(GOR)on residual-oil saturation(ROS)and oil-water relative permeability.By adopting the ROS and relative permeability associated with the 50%v/v breaker fluid mixture,the performance of the hydrocarbon reservoir was numerically simulated under the limiting scenarios of no-invasion,moderate-invasion,and deep-invasion of breaker fluid.The results indicate a positive correlation between breaker fluid concentration and ROS,highlighting the risks that breaker fluid invasion and deep infiltration pose to hydrocarbon recovery.Further,results show that both live-oil condition(LOC)and dead-oil condition(DOC)reservoirs are susceptible to the detrimental impacts of breaker fluid infiltration,while their invasion can reduce hydrocarbon recovery in both LOC(-6%)and DOC(-28%).The multi-scale effects on reservoir performance are more pronounced at near-wellbore and DOC than at far-field and LOC.Findings from this work provide valuable insights into the complexity of breaker-fluid invasion in sandstone reservoirs and the mitigation of associated risks to reservoir performance.

An Optimised Surface Structure for Passive, Unidirectional Fluid Transport Bioinspired by True Bugs

Some true bug species use droplet-shaped,open-capillary structures for passive,unidirectional fluid transport on their body surface in order to spread a defensive fluid to protect themselves against enemies.In this paper we investigated if the shape of the structures found on bugs(bug-structure)could be optimised with regard to better performance in unidirectional fluid transportation.Furthermore,to use this kind of surface structure in technical applications where fluid surface interaction occurs,it is necessary to adapt the structure geometry to the contact angle between fluid and surface.Based on the principal of operation of the droplet-shaped structures,we optimised the structure shape for better performance in targeted fluid flow and increase in flexibility in design of the structure geometry.To adapt the structure geometry and the structure spacing to the contact angle,we implemented an equilibrium simulation of the,the structure surrounding,fluid.In order to verify the functionality of the optimised structure,we designed and manufactured a prototype.By testing this prototype with pure water used as fluid,the functionality of the optimised structure and the simulation could be proved.This kind of structure may be used on technical surfaces where targeted fluid transport is needed,e.g.evacuation of condensate in order to prevent the surface from mold growth,microfluidics,lab-on-a-chip applications and on microneedles for efficient drug/vaccine coating.

Photothermally induced liquid gate with navigation control of the fluid transport

The ability to control multiphase flows is essential for applications such as microvalves,chemical analyses,mi-croreactors,and multiphase separators.Furthermore,more specific controls,including the positional naviga-tion control of fluids under steady-state pressures,will improve the development of these applications.Here,we present a fundamentally new photothermally induced liquid gating system that allows light-controlled con-tactless fluid transport and gas/liquid separations at designated locations,with seconds response times,under constant pressures.Experiments and theoretical calculations demonstrate the stability of our system and its novel regulation mechanism,which is based on a photothermally induced liquid-reconfigurable gate with a change in the surface/interfacial tension and Marangoni flow redistribution of the gating liquid at the illuminated location.This regulation mechanism with positional navigation properties requires neither mechanical parts nor complex accessories and can further enable the miniaturization and integration of various engineering processes.Our ap-plication demonstrations confirm the potential of this system in fields of smart valves,multiphase separations,multiphase microreactors,and beyond.

Lagrangian analysis of the fluid transport induced by the interaction of two co-axial co-rotating vortex rings

In this paper,the fluid transport in the interaction of two co-axial co-rotating vortex rings are investigated.Vortex rings are generated using the piston-cylinder apparatus,and the resulting velocity fields are measured using digital particle image velocimetry.The interaction process is analysed by means of vorticity contour,as well by investigation of the Lagrangian coherent structures(LCSs)defined by the ridges of the finite-time Lyapunov exponent(FTLE).Experimental results demonstrate that two types of vortex interaction are identified,namely strong and weak interactions,respectively.For the strong interaction,the Lagrangian boundaries of the two vortex rings are merged together and form a flux window for fluid transport.For weak interaction,only the Lagrangian drift induced by the motion of the front vortex ring is observed and affects the Lagrangian boundary of the rear vortex ring.Moreover,the fluids transported in the strong interaction carry considerable momentum but no circulation.By contrast,there are nearly no fluxes occurring in the weak interaction.By tracking the variations of circulation and impulse occupied by the separated regions distinguished by the LCSs,it is found that the circulation nearly has no change,but the impulse occupied by vortex core region has significant change.In the strong interaction,the impulse of rear vortex ring decreases but the impulse of the front vortex ring increases.Based on the impulse law,it is speculated that the fluid force generated by the formation of the rear vortex rings can be enhanced.Therefore,the strong interaction between wake vortices can actually improve the propulsive efficiency of the biological systems by operating the formation of large-scale vortices.

Numerical simulation of a dense solid particle flow inside a cyclone separator using the hybrid Euler-Lagrange approach

This paper presents a numerical simulation of the flow inside a cyclone separator at high particle loads. The gas and gas–particle flows were analyzed using a commercial computational fluid dynamics code. The turbulence effects inside the separator were modeled using the Reynolds stress model. The two phase gas–solid particles flow was modeled using a hybrid Euler–Lagrange approach, which accounts for the four-way coupling between phases. The simulations were performed for three inlet velocities of the gaseous phase and several cyclone mass particle loadings. Moreover, the influences of several submodel parameters on the calculated results were investigated. The obtained results were compared against experimental data collected at the in-house experimental rig. The cyclone pressure drop evaluated numerically underpredicts the measured values. The possible reason of this discrepancies was disused.

Effects of Nectar Property on Compensated Dipping Behavior of Honey Bees with Damaged Tongues

In nature,bees with damaged tongues are adapted to have a feat in collecting nectariferous sources in a large spectrum of concentrations(19%-69%)or viscosities(10^(-3)Pa·s to 10^(-1)Pa·s);however,eff ects of nectar property on compensated dipping behavior remain elusive.Combining the bee tongue anatomy,high-speed videography,and mathematical models,we investigate responses of honey bees with damaged tongues to fluidic sources in various properties.We find that,bees with 80%damaged tongues are deprived of feeding capability and remarkably,the dipping frequency increases from 4.24 Hz to 5.08 Hz while ingesting 25%sugar water when the tongue loses 0-30%in length,while declines from 5.08 to 3.86 Hz in case of 30%damaged tongue when sucrose concentration increases from 25%to 45%.We employ the energetic compensation rate and energetic utilization rate to evaluate eff ectiveness of the compensation from the perspective of energetic regulation.The mathematical model indicates that the energetic compensation rate turns higher in bees with less damaged tongues for ingesting dilute sugar water,demonstrating its capability of functional compensation for combined factors.Also,the tongue-damaged bees achieve the highest energetic utilization rate when ingesting~30%sugar water.Beyond biology,the findings may shed lights on biomimetic materials and technologies that aim to compensate for geometrical degradations without regeneration.