Analyzing Impacts of Interfacial Instabilities on the Sweeping Power of Newtonian Fluids to Immiscibly Displace Power-Law Materials

Injection of Newtonian fluids to displace pseudoplastic and dilatant fluids, governed by the power-law viscosity relationship, is common in many industrial processes. In these applications, changing the viscosity of the displaced fluid through velocity alteration can regulate interfacial instabilities, displacement efficiency, the thickness of the static wall layer, and the injected fluid’s tendency to move toward particular parts of the channel. The dynamic behavior of the fluid–fluid interface in the case of immiscibility is highly complicated and complex. In this study, a code was developed that utilizes a multi-component model of the lattice Boltzmann method to decrease the computational cost and accurately model these problems. Accordingly, a 2D inclined channel, filled with a stagnant incompressible Newtonian fluid in the initial section followed by a power-law material, was modeled for numerous scenarios. In conclusion, the results indicate that reducing the power-law index can regulate interfacial instabilities leading to dynamic deformation of static wall layers at the top and the bottom of the channel. However, it does not guarantee a reduction in the thickness of these layers, which is crucial to improve displacement efficiency. The impacts of the compatibility factor and power-law index variations on the filling pattern and finger structure were intensively evaluated.</p

Study of geothermal energy potential as a green source of energy with a look at energy consumption in Iran

Regarding disadvantages of fossil fuels, renewables like geothermals can be an eco-friendly source of energy. In Iran, the availability of fossil fuels and poor policies surrounding subsidies (ranked as the first in giving subsidies) caused high energy consumption (1.75 times higher than the global average). Energy is mainly provided by fossil fuels that leads to high CO$_{2}$ emission. This study evaluates the energy consumption trend and potentials of more sustainable resources like geothermals in Iran. The formation of geothermals is tightly linked with geological prerequisites that are partly present within Iran. Adjacency of the metamorphic with volcanic zones, existence of numerous faults and seismic activity of Iran are notable geological characteristics confirming the geothermal potential. In Iran, 18 regions are being explored as the most promising geothermal prospects. To test the potentials of one of these regions, a geothermal power plant with a capacity of 5 MWe is installed in the Sabalan Field. Northwest (where Sabalan Field is located), central (like Mahalat Region) and southeast of Iran (Makran Zone) can be regarded as promising zones for hosting geothermal prospects

Implications on large-scale flow of the fractured EGS reservoir Soultz inferred from hydraulic data and tracer experiments

The Enhanced Geothermal System in Soultz-sous-Forêts, located in the geothermal favorable Upper Rhine Graben, is a fracture-controlled reservoir that was highly investigated in the last decades generating a huge geoscientific database. Numerical reservoir models use this database to simulate the operation of the subsurface heat exchanger, yet suffer from simplifications regarding the transfer of experimental into model data, dimensional extension, and computational power and efficiency. The new extensive transient 3D simulations, based on geophysical, geological and hydraulic data, highlight the hydraulic and transport feedback of the Soultz EGS due to convective and advective fluid flow. Developed with the goal of simulating the vast tracer test data during the reservoir-testing phase in 2005, the finite element model is focusing on the main fractured zones, which connect the wells in the deep reservoir. It comprises 13 major hydraulically active faults and fractures in a 13×11 x 5 km extending model domain, as well as open-hole sections of the wells GPK1 to GPK4 and their casing leakages. The simulation of the tracer experiment confirms the strong heterogeneity of the reservoir and highlights the importance of a potential fractured zone, hydraulically separating the reservoir in a northern (GPK1 to 3) and southern section (GPK4). This zone tends to connect the reservoir to the main fault system by hydraulically separating GPK4 from the other wells. The calibration and sensitivity analyses provide a unique, broad understanding of the reservoir flow zones providing information on the extension of the Soultz reservoir in the future and on the fluid pathways in the deep subsurface of the Upper Rhine Graben

Stochastic 3D Navier‐Stokes Flow in Self‐Affine Fracture Geometries Controlled by Anisotropy and Channeling

This study presents a probabilistic analysis of 3D Navier‐Stokes (NS) fluid flow through 30 randomly generated sheared fractures with equal roughness properties (Hurst exponent = 0.8). The results of numerous 3D NS realizations are compared with the highly simplified local cubic law (LCL) solutions regarding flow orientations and regimes. The transition between linear and nonlinear flow conditions cannot be described with a generally valid critical Reynolds number urn:x-wiley:00948276:media:grl62319:grl62319-math-0001, but rather depends on the individual fracture\u27s void geometry. Over 10% reduction in flow is observed for increased global Re (>100) due to the increasing impact of nonlinear conditions. Furthermore, the fracture geometry promotes flow anisotropy and the formation of channels. Flow perpendicular to the shearing leads to increased channeling and fluid flow (∼40% higher) compared to flow parallel to the shearing. In the latter case, dispersed flow and irregular flow paths cause a reduction of LCL validity

A Fully-Coupled Implicit Transient Two-Phase Wellbore Simulator

Boreholes under operation conditions typify a highly non-linear and complexly coupled thermo-hydraulic-chemical (THC) system. Multiple parameters, such as temperature, pressure, specific heat, enthalpy, viscosity, flow regime, heat transfer, degassing, steam quality, salinity and solubility are inter connected. Production and injection often entail several engineering challenges and operational problems within the boreholes but also up and down stream (reservoir-power plant-reservoir), which can be very diverse in their character. Finding solutions or working on process optimization prerequisite a profound understanding and a reliable tool to quantify these processes. Compared to reservoirs, the processes in boreholes are highly dynamic and fluctuating. Most existing simulators provide either only steady state solutions or are based on a just weakly coupled numerical scheme. We develop a new tool solving for the aforementioned parameters in a fully-coupled, implicit, and transient manner, which is a prerequisite to realistically model dynamic borehole conditions. Herein, we present the current state of the development of the simulator for multicomponent non-isothermal two-phase flow. To demonstrate the capabilities of the code, validation results and synthetic test cases for compressible single-phase flow as well as two-phase drift-flux are shown. Applications of such a tool are manifold. It can be used for exploration in early stages of the reservoir development, to constrain the static formation temperature (SFT) from logging data measured under dynamic production/injection conditions. What-if-calculations support the design and dimensioning of future power plants. Optimization of production and injections scenarios are more reliable when they are based on solid quantifications of thermo-hydraulic borehole processes. Furthermore, borehole simulation can also be the basis for managing the complex handling of co-produced noncondensable gases or preventing scaling formation and steel corrosion

Appraising Mahallat Geothermal Region using thermal surveying data accompanied by the geological, geochemical and gravity analyses

Mahallat Geothermal Region, located in the central part of Iran, is known as one of the largest lowtemperature geothermal fields. In this study, Mahallat geothermal resource has been evaluated based on integrated geological, geochemical and geophysical analyses. Gravity data revealed three major negative anomaly zones. Based on the geochemical analyses, quartz geothermometers are more reliable than others and confirmed that the reservoir is about 90 °C. Lithological properties of Jurassic layers and high sulphate content observed in geochemical data showed traces of the coalrich layers on the hot fluids. Measured temperatures in 7 boreholes with the depths ranging from 50 to 100 m, have proposed that expected geothermal gradient will be about 81.5 °C/km. Among all drilled boreholes, the data coming from only one resulted in this almost reliable gradient. Other boreholes are clearly too shallow or affected by upflow or downflow of water along existing faults. Geological, geochemical, gravity and measurements of drilled boreholes suggested the existence of a shallow reservoir with an approximate temperature of 90 °C. Regarding gravity and observed faults, geothermal reservoir is elongated parallel to one of the main faults of the region with NE-SW strike