Fluid Displacement Research Articles

Review and perspectives of microfluidic chips in energy geology

Microfluidic chips represent visualization-enabled miniaturized analytical platforms that serve as powerful investigative tools for multiscale process characterization, enabling multiscale analysis from pore-level processes to macroscopic system behaviors. These systems provide high-resolution insights into fluid–rock interactions within geological formations, where multiphase flow dynamics and biogeochemical processes fundamentally control hydrocarbon recovery efficiency and subsurface storage performance. At the microscale, fluid–solid interfacial phenomena dictate multiphase displacement mechanisms across diverse lithologies, while microfluidic platforms accurately replicate subsurface flow conditions in hydrocarbon reservoirs, coal seams, and gas-bearing formations through geometrically constrained microenvironments. This review systematically examines the technological implementation of microfluidic chips in subsurface reservoir engineering, specifically categorized into four strategic areas: geological carbon sequestration, underground hydrogen storage, gas hydrate/coalbed methane extraction, and enhanced oil recovery. Across these applications, microfluidic systems primarily function to decode immiscible fluid displacement physics under reservoir-relevant conditions. Systematic investigations have identified critical governing factors including interfacial wettability, viscosity contrast, injection dynamics (flow rate/pressure), thermodynamic conditions, pore-throat geometry, surface morphology, reservoir heterogeneity, and microbial mediation. Integration of these microscale findings enhances predictive capabilities in macroscopic simulations such as core flooding experiments and reservoir-scale flow modeling, ultimately advancing strategic optimization of energy resource management and environmental sustainability at engineering-relevant scales. Meanwhile, microchips face challenges such as scale mismatch and limited material performance in actual geological simulations. In the future, technological innovation in the field of energy geology can be promoted by developing high-performance chip materials and establishing multiscale coupling experimental platforms.

Computer Modeling of the Process for Manufacturing Spherical Vessels from Sheet Steel by Hydroforming

Reliable and safe operation of vessels filled with gas or liquid under high pressure requires compliance with certain requirements for their strength. It is also important to reduce weight and material consumption. Numerous industries, including automotive, chemical engineering, and the rocket and space industry, which supply products in bulk, effectively use hydroforming technology for the manufacture of components. Hydroforming is a metalworking process in which complex-shaped structures are created using fluid pressure and displacement constraints instead of traditional mechanical loads (or in combination with them). The successful implementation of this technology is possible due to the advantages that hydroforming has compared to traditional methods, such as the assembly of blankings by welding. A simulation of the manufacture of spherical vessels from sheet steel by hydroforming is proposed in this paper. The software developed on the basis of the finite element method is used, which allows solving elastoplastic problems of thermomechanics by time or load steps in combination with an iterative process on each of them, during which the geometry of the deformed part is refined. To describe the stress-strain state, a logarithmic measure of deformations is used, which allows reflecting real processes occurring in the workpiece. Plastic deformations are taken into account using deformation theory. Thanks to computer modeling of hydroforming technology, spherical models that have the lowest metal content at high pressure were obtained. The obtained vessel models deform elastically under repeated loading due to an increase in the yield strength of the material, therefore they will not be damaged by low-cycle fatigue. They can be used in aerospace engineering as fuel tanks for liquefied oxygen or fluorine and hydrogen. Computer modeling of the hydroforming process allows to quickly and cheaply set the parameters of vessels of various sizes and from different materials, and to obtain an acceptable result without resorting to multiple experimental attempts.

Combined Effect of Viscosity Ratio and Interfacial Tension on Residual Saturations: Implications for CO2 Geo-Storage

This work examines how multiphase flow behavior during CO2 and N2 displacement in a microfluidic chip under capillary-dominated circumstances is affected by interfacial tension (IFT) and the viscosity ratio. In order to simulate real pore-scale displacement operations, microfluidic tests were performed on a 2D rock chip at flow rates of 1, 10, and 100 μL/min (displacement of water by N2/supercritical CO2). Moreover, core flooding experiments were performed on various sandstone samples collected from three different geological basins in Australia. Although CO2 is notably denser and more viscous than N2, the findings show that its displacement efficiency is more influenced by the IFT values. Low water recovery in CO2 is the result of non-uniform displacement that results from a high mobility ratio and low IFT; this traps remaining water in smaller pores via snap-off mechanisms. However, due to the blebbing effect, N2 injection enhances the dissociation of water clots, resulting in a greater swept area and fewer remaining water clusters. The morphological investigation of the residual water indicates various displacement patterns; CO2 leaves more retained water in irregular shapes, while N2 enables more uniform displacement. These results confirm earlier studies and suggest that IFT has a crucial role in fluid displacement proficiency in capillary-dominated flows, particularly at low flow rates. This study emphasizes the crucial role of IFT in improving water recovery through optimizing the CO2 flooding process.

Математическое описание принципа магнитогидродинамического перемещения электропроводящих нефтесодержащих жидкостей

The magnetohydrodynamic principle is an important interdisciplinary field. In modern conditions of development of the technical design of oil extraction, there is a need for magnetohydrodynamic equipment that allows automating complex processes in oil product extraction technology and increasing their degree of mechanization, as well as saving energy and resources while increasing environmental safety. One of the most important applications of this effect is the pumping of materials, which is currently carried out by conventional low-efficiency pumping units. To solve the problem of increasing the efficiency of the indicated operation using magnetohydrodynamic technology, it is advisable to use modeling, which makes it possible to replace the original with its mathematical counterpart. Due to the complexity of the analyzed operations, the indicated devices consider only substantially idealized model schemes that are not acceptable for studying their statics and dynamics, as well as the synthesis of automatic control complexes, which determines the relevance of constructing a model that corresponds to the physical control mechanism of the studied objects. The article de-scribes in detail the physical principle of operation of MHD devices based on the interaction of an electric current passed through an electrically conductive liquid (in this case, a watered reservoir fluid, which is an electrolyte) and a high-intensity magnetic field perpendicular to it. The Lorentz force resulting from this interaction and leading to fluid displacement is described. The design scheme of the MHD pump is presented and its main advantages (compactness, thermal stability, absence of moving elements, reliability, relatively high efficiency (UAC), short transient time interval, low maintenance, ease of operation at the microlevel, high specific power) and disadvantages (problems of superconducting technologies, edge effects of the magnetic field, bulky dimensions) are considered. magnetic elements, lack of correct analytical models, uneven velocity profile and flow instability).

Chemical incompatibility between formation and injection water: implications for oil recovery in porous media.

Low-salinity water flooding is widely recognized as an effective enhanced oil recovery (EOR) method, primarily by altering wettability and reducing interfacial tension. However, chemical incompatibility between injected water and formation water may induce scale deposition, leading to pore blockage and injectivity impairment, thereby posing significant challenges to EOR efficiency. A better understanding of the interplay between chemical incompatibility and pore-scale oil-water interface dynamics is crucial for optimizing waterflooding performance, particularly in low-permeability reservoirs. This study integrates ion characterization, colloidal analysis, solubility product calculations, and microfluidic visualization to systematically evaluate the compatibility of formation and injected waters, while directly observing pore-scale fluid displacement processes. Results reveal that ionic composition analysis reveals significant incompatibility between the sulfate-rich injection water and calcium/barium-containing formation water, creating conditions favorable for mineral scaling. Subsequent examination of scaling dynamics demonstrates that incompatible fluid mixing initiates nanoparticle formation, which progresses through two distinct growth pathways: coalescence-driven crystal enlargement and aggregation-dominated cluster formation, ultimately leading to pore-throat obstruction. Microfluidic visualization shows residual oil persists primarily as interfacial films and pore-center clusters after initial waterflooding, with their spatial arrangement governed by salinity-dependent wettability alteration and capillary forces. The introduction of incompatible water further exacerbates fluid trapping through capillary valve effects-a capillary-driven resistance occurring when interfacial forces oppose fluid advancement at pore-throat junctions-creating stagnant zones that promote particle accumulation. Pressure monitoring during flooding experiments reveals characteristic response patterns: an initial pressure peak during waterflooding, followed by secondary pressure elevation due to scale deposition, and subsequent partial pressure reduction through surfactant-mediated interfacial tension reduction and wettability modification. A self-reinforcing cycle emerges, coupling ion incompatibility, capillary trapping, and precipitate growth, encapsulated in a colloid-capillary coupling framework. To disrupt this cycle, a synergistic chemical strategy combining surfactants and scale inhibitors is proposed, simultaneously enabling interface modification and nucleation suppression to enhance sweep efficiency. This integrated approach provides a mechanistic foundation for optimizing waterflooding in chemically complex reservoirs, achieving a balanced synergy between interfacial control and scale mitigation.

Viscous flow through high-permeability channels in a layered porous medium

Viscous flow through high-permeability channels occurs in many environmental and industrial applications, including carbon sequestration, groundwater flow and enhanced oil recovery. In this work, we study the displacement of a less-viscous fluid by a more-viscous fluid in a layered porous medium in a rectilinear configuration, where two low-permeability layers sandwich a higher-permeability layer. We derive a theoretical model that is validated using corroborative laboratory experiments, when the influence of the density difference is negligible. We find that the location of the propagating front increases with time according to a power-law form $x_f \propto t^{1/2}$ , while the fluid–fluid interface exhibits a self-similar shape, when the motion of the displaced fluid is negligible in an unconfined porous medium. In the experimental set-up, distinct permeability layers were constructed using various sizes of spherical glass beads. The working fluids comprised fresh water as the less-viscous ambient fluid, and a glycerine–water mixture as the more-viscous injecting fluid. Our experimental measurement show a better match with the theory for the experiments performed at low Reynolds numbers and with permeable boundaries in the far field.

Spaceflight Associated Neuro-Ocular Syndrome as a Potential Variant of Venous Overload Choroidopathy

INTRODUCTION: Novel ocular findings have been identified in spaceflight. We discuss their potential association with Spaceflight Associated Neuro-ocular Syndrome (SANS) and integrate them in a framework that may help explain the pathophysiology. METHODS: We reviewed literature using the Medline/PubMed database starting in October 2020. Search terms included ocular circulation, hyperopia, serous chorioretinopathy, pigment epithelial detachment, choroidal folds, choroidal thickening, pachychoroid disease, optic disc edema, venous overload choroidopathy. No date exclusions were placed on the search. Articles were reviewed for relevance. Articles relevant to the pathophysiology of choroidal thickening and choroidal venous overload as it applies to SANS were included. RESULTS: Terrestrial venous overload choroidopathy is thought to be due to impediment to choroidal venous outflow, resulting in dilation of choroidal veins, increased choroidal thickness, pigment epithelial detachments, and serous detachment of the retina. Serous detachment of the retina, pigment epithelial detachments, choroidal folds, and thickening of the choroid were identified on in-flight optical coherence tomography testing. Postflight findings include these, as well as globe flattening. During spaceflight, there is a cephalad displacement of both blood and cerebrospinal fluid. This may lead to pathological consequences in the eye. Remodeling of the choroidal venous vortex system may result in continuance of pathophysiological findings after return to Earth, suggesting the best strategy is prevention. DISCUSSION: Microgravity induced venous overload of the choroid may play a role in SANS pathophysiology, and a venous overload choroidopathy may help explain several SANS features that remain unexplained by an etiology of elevated intracranial pressure. Mampre D, Spaide R, Mason S, Van Baalen M, Gibson CR, Mader TH, Wostyn P, Briggs J, Brown D, Lee AG, Patel N, Tarver W, Brunstetter T. Spaceflight-Associated Neuro-ocular Syndrome as a potential variant of venous overload choriodopathy. Aerosp Med Hum Perform. 2025; 96(6):496–508.

Calcium carbonate amorphous-to-crystalline transition drives complex precipitation patterns in confined fluids.

Calcium carbonate amorphous-to-crystalline transition drives complex precipitation patterns in confined fluids.

Experimental Study on Fracturing Fluid Damage of Tight Sandstone Reservoirs Based on Nuclear Magnetic Resonance Technology

This study based on nuclear magnetic resonance (NMR) technology, systematically evaluated the microscopic damage mechanism of fracturing fluids on tight sandstone reservoirs. Through core displacement experiments, combined with permeability tests and T2 spectrum analysis, the impact of fracturing fluids on the pore structure and seepage capacity of the reservoir was quantified. The experimental results showed that the core permeability significantly decreased (35.76% to 66.41%) after fracturing fluid displacement, with an average matrix damage rate of 54.55%. The NMR T2 spectrum indicated that the high-molecular components in the fracturing fluid preferentially invaded and adhered to the medium and large pores, causing their pore size distribution to shift towards micro and small pores, and the overall pore volume decreased. X-ray diffraction analysis revealed that the water-induced swelling of clay minerals further exacerbated the blockage of medium to large pore throats, destroying the seepage channels. The study confirmed that the main cause of damage to tight sandstone reservoirs was the physical blockage of medium to large pore throats by fracturing fluids and the water sensitivity effect of clay minerals, providing key experimental evidence for the optimization of fracturing fluid formulations and reservoir protection.

Evaluating needle-free connectors associated backflow in Midline and peripherally inserted central catheters: A top bench study.

Needle-free connectors (NFCs) are closure systems for vascular catheters largely used because effectively reduce needlestick incidents. They are classified based on their impact on the fluid column within the catheter as positive (fluid displacement into the vein), negative (fluid displacement back from the vein into the catheter), neutral (minimal displacement), or anti-reflux (equipped with additional anti-reflux valve). Each category has specific usage and clamping procedures. This study aimed to evaluate the backflow volume (BV) when different NFC categories and clamping sequences are used with a peripherally inserted central catheter (PICC) and a Midline catheter (MC). In this bench study, four types of NFCs with different flow displacement behavior were studied. Each NFC was evaluated using two different catheters: a 4 Fr × 60 cm single-lumen catheter (PICC), and a 4 Fr × 25 cm single-lumen catheter (MC). The experimental model simulated the physiological blood pressure of the superior vena cava. Three operators performed specific sealing sequences for each combination of NFC and catheter. After that, the BV (mm3) inside the catheter for every NFC was assessed. None of the four NFCs was able to avoid the BV into the catheter. Positive NFC showed a lower BV as compared to the other three NFCs when tested with PICC: 0.83 [0.76-0.95] mm3 versus 1.14 [0.95-1.53] mm3 of Q-SYTE, versus 1.27 [1.02-1.59] mm3 of Neutron, versus 1.24 [0.95-1.84] mm3 of Bionector, whereas no differences were observed when tested with Midline. No differences were observed between different clamping sequences when used with neutral and anti-reflux NFCs. This study examined the performance of various NFC technologies with PICC and Midline. While no device eliminates BV, positive displacement NFCs showed lower flow reflux compared to the others when used with PICC. No difference between clamping sequences was observed for neutral and anti-reflux NFCs.

Rectilinear drift and oscillation of a rotating cylinder placed in flow

The system composed of a circular cylinder free to move along a transverse rectilinear path within a cross-current has often served as a canonical problem to study the vortex-induced vibrations (VIV) developing in the absence of structural restoring force, thus without structural natural frequency. The object of the present work is to extend the exploration of the behaviour of this system when the path is set to an arbitrary orientation, varying from the transverse to the streamwise direction, and the cylinder is forced to rotate about its axis. The investigation is conducted numerically at a Reynolds number equal to $100$ , based on the body diameter and oncoming flow velocity, for structure to displaced fluid mass ratios down to $0.01$ and values of the rotation rate (ratio between body surface and oncoming flow velocities) ranging from $0$ to $1$ . When the transverse symmetry is broken by the orientation of the trajectory or the forced rotation, the cylinder drifts along the rectilinear path, at a velocity that can be predicted by a quasi-steady approach. Three distinct regimes are encountered: a pure drift regime, where the body translates at a constant velocity, and two oscillatory regimes, characterised by contrasted forms of displacement fluctuation about the drifting motion, but both closely connected to flow unsteadiness. VIV, nearly sinusoidal, persist over a wide range of path orientations, for all rotation rates. On the other hand, irregular jumps of the body, triggered by the rotation and named saccades, emerge when the trajectory is aligned, or almost aligned, with the current. The two forms of response differ by their regularity, but also by their amplitudes and frequencies, which deviate by one or more orders of magnitude. The rotation attenuates both VIV and saccades. Yet, an increase of the rotation rate enhances the erratic nature of the saccade regime.

Effectiveness of Foot Massage on Blood Pressure and Quality of Life in Pregnant Women with Preeclampsia

Background: Foot massage has been shown to enhance peripheral circulation, mechanically aid lymphatic and venous fluid displacement, and modify nerve, blood vessel, and cell structures in the exchange network. Objective: To evaluate the effectiveness of foot massage on blood pressure and quality of life in pregnant women with preeclampsia. Methodology: This randomized controlled trial was conducted at the DHQ Teaching Hospital and Aziz Fatima Hospital, Faisalabad, in 4 months. About 28 participants were pregnant women aged between 25 and 35 years. The treatment group received a foot massage along with the continued hypertensives and the control group received medication only. The Quality of Life Questionnaire for Pregnancy was used to assess the quality of life before and after the treatment during pregnancy. Participants were divided into two groups by the lottery method. An even number of participants were added to the treatment group (Group A), and an odd number of participants were added to the control group (Group B). Foot massage consists of five techniques: effleurage, petrissage, tapotement, friction, and vibration, and is performed for 20 minutes per session, 10 minutes for each foot. Blood pressure was measured 15 minutes before and after the foot massage. The quantitative data were presented as means and standard deviations, while the qualitative data were reported as frequencies and percentages. A chi-square test was used to compare to observed results with the expected results. Statistical significances were determined at a significance level of p-value of 0.05. Results: The highest proportion of participants (39.3%) were in the 29 to 32 week range of gestation, while 10.7% were in the 39 to 40 week range. In terms of pregnancy status, a slight majority were primigravida (53.6%), with the remaining 46.4% being multigravida. Changes in blood pressure were assessed over six days of treatment using the Friedman test. Both the intervention and control groups showed significant reductions in blood pressure. Conclusion: Foot massage in combination with hypertensive medication was found to be a more effective treatment option to reduce blood pressure and improve quality of life in pregnant females with preeclampsia as compared to hypertensive medications alone.

Insights Into Interfacial Dynamic and Displacement Patterns During Immiscible Two‐Phase Porous Media Flow Under Controlled Viscosity and Wettability Conditions

Abstract Multiphase flow in porous media is fundamental to various geological processes, including carbon capture, geothermal energy production, and enhanced oil recovery. However, the role of fluid properties and surface wettability in determining displacement patterns during flow remains not fully understood. This study addresses this gap by examining the effects of fluid viscosity and wettability on two‐phase flow through porous media using a combination of microfluidic experiments and high‐resolution numerical simulations. Our findings indicate that viscosity and wettability significantly influence the morphology of fluid displacement, with lower viscosity ratios leading to viscous finger‐like invasion patterns, while higher viscosity ratios result in more compact displacement fronts. A significant increase in interface area generation is identified during the transition from compact displacement to viscous flow. This aligns with the energy balance analysis, which reveals that a greater portion of the injected fluid energy is expended on creating new interfaces. Wettability also plays a critical role in displacement patterns, especially under intermediate conditions, causing more interfacial dynamics than water‐wet and oil‐wet conditions. These insights advance our understanding of pore‐scale mechanisms and contribute to more accurate multiphase flow models, ultimately informing applications in resource extraction and underground fluid management.

Thermoresponsive Film Enhances Fluid Migration within the Capillary under a Dynamic Wettability Gradient.

The study developed a thermoresponsive film to achieve autonomous fluid driving in microfluidic channels, simplify microfluidic systems, and improve their operability. This film has a lower critical solution temperature (LCST), exhibiting different wettabilities on each side of the LCST, and showed improved hydrophilicity-to-hydrophobicity conversion with increased substrate roughness, maintaining stability after repeated cycles. The thermoresponsive film was applied to the inner wall of the glass capillary, which showed a hydrophilic and enhanced capillary effect below the LCST and a hydrophobic and weakened capillary effect above the LCST. Subsequently, the modified capillary was placed under a dynamic temperature gradient, and the force analysis of the fluid in the flow channel was carried out. It was found that only when the driving force exceeded the axial resistance could the fluid migrate. Experimental analysis showed that fluid length was directly proportional to axial resistance and inversely proportional to both driving force and migration velocity at a constant dynamic temperature gradient. Additionally, the temperature of the hot end of the capillary was varied to form different dynamic temperature gradients. A higher dynamic temperature gradient resulted in greater fluid displacement and velocity at a constant fluid length. The results presented in this study were expected to provide new insights into the design and optimization of thermally driven microfluidic systems.

Simulation of CO2–water two‐phase fluid displacement characteristics based on the phase field method

Abstract The two‐phase flow in porous media is affected by multiple factors. In the present study, a two‐dimensional numerical model of porous media was developed using the actual pore structure of the core sample. The phase field method was utilized to simulate the impact of displacement velocity, the water–gas viscosity ratio, and the density ratio on the flow behavior of two‐phase fluids in porous media. The effectiveness of displacement was evaluated by analyzing CO2 saturation levels. The results indicate that the saturation of CO2 in porous media increased as the displacement velocity increased. When the displacement velocity exceeded 0.01 m/s, there was a corresponding increase in CO2 saturation. Conversely, when the displacement velocity was below this threshold, the impact on CO2 saturation was minimal. An “inflection point,” M3, was present in the viscosity ratio. When the viscosity of CO2 is less than 8.937 × 10−5 Pa·s (viscosity ratio below M3), variations in the viscosity of CO2 had little impact on its saturation. Conversely, when the viscosity of CO2 exceeded 8.937 × 10−5 Pa·s (viscosity ratio greater than M3), saturation increased with an increase in the viscosity ratio. In terms of the density ratio, the saturation of CO2 increased monotonically with an increase in the density ratio. Similarly, increasing density ratios resulted in a monotonic increase in CO2 saturation, though this trend was less pronounced in numerical simulations. Analysis results of displacement within dead‐end pores using pressure and velocity diagrams reveal eddy currents as contributing factors. Finally, the impact of pore throat structure on the formation of dominant channels was examined.

Immiscible fluid displacement: From pore doublets to porous media

Immiscible fluid displacement: From pore doublets to porous media

Α Python-based Evaluation of Kazakhstan's Fields for Carbon Capture, Utilization, and Storage Projects

The purpose of this study is to evaluate the feasibility of different oil fields in Kazakhstan for Carbon Capture, Utilization, and Storage (CCUS) projects using advanced algorithms in Python. Using automated methods, the approach greatly simplifies and accelerates the selection process, allowing efficient analysis of large data sets. Taking into account key geological and operational parameters, with particular emphasis on the importance of the Dykstra-Parsons coefficient, the study presents a comprehensive ranking system for evaluating reservoir suitability. This coefficient is critical to accurately assess the fluid displacement efficiency, which significantly influences the selection of candidates for Enhanced Oil Recovery (EOR). The results show that the inclusion of the Dykstra-Parsons coefficient improves the accuracy of field evaluation by accounting for key reservoir heterogeneity factors along with conventional properties. The comparative analysis shows that this approach provides more reliable field selection compared to the existing methods that do not consider this parameter, thereby improving the efficiency of CO2 storage projects.

Biomechanical simulations of intracerebral hemorrhage expansion show tissue displacement has significant impact on electrical impedance tomography results.

Intracerebral hemorrhage (ICH) occupies intracranial space and causes brain tissue displacement and fluid volume shifts. We assess how hematoma expansion (HE) affects electrical impedance tomography (EIT) measurements and reconstructed images of the conductivity change caused by HE. We developed a novel multi-physics model of ICH with mechanical tissue deformation during HE. We simulated EIT measurements with the multi-physics model and a traditional static model using five ICH locations. The effects of tissue deformation on the results of monitoring of ICH with EIT were assessed by comparing the measurement data from the multi-physics and traditional models and by comparing the corresponding reconstructed conductivity change from two image reconstruction algorithms. The simulated measurement data and the reconstructed images of the conductivity change using the multi-physics and the traditional model are radically different regardless of the image reconstruction algorithm used. The effect of tissue displacement caused by HE on EIT monitoring of ICH is significant. Specifically, the displacement of cerebrospinal fluid (CSF) can mask the effects of increased ICH blood volume. However, the effects of displaced CSF could be easier to detect with EIT than the ICH blood volume increase and thus could be used as an indicator of HE in EIT bedside monitoring of ICH and improve the detectability of HE, especially for ICH located deep in the brain. Currently there are virtually no imaging methods for continuous monitoring of stroke. There has been recent resurgence in interest to develop electrical impedance tomography (EIT) devices and algorithms for monitoring progression of stroke. In-silico studies show promising results, but there are very little clinical results. In-silico models are usually used for development and evaluation of algorithms for EIT image reconstruction. In previous studies the stroke has been usually modeled as local change in electrical conductivity and the fluid and tissue displacement caused by the increased blood volume in ICH has not been considered. In this paper we present a novel multi-physics model of ICH, simulated EIT measurement results and reconstructed images with comparisons to the traditionally used ICH modeling methods. Our multi-physics approach to modeling of ICH shows that the effect of tissue and fluid displacement during HE needs consideration when developing clinical applications of EIT.

Stability analysis of miscible displacement by non-Newtonian nanofluid with different diffusion coefficients

This paper investigates the effect of nanoparticles on the thermo-viscous fingering instability of non-Newtonian fluids during miscible displacements in homogeneous porous media. Nanoparticles are added to the fluid with variable and constant diffusion coefficients, and both the displacing fluid and the displaced fluid are considered as non-Newtonian fluids. The results indicate that the nanoparticles demonstrate efficacy in mitigating the thermo-viscous fingering instability when variable diffusion coefficients are employed, in contrast to scenarios where constant diffusion coefficients are utilized. In contrast to the situation with a constant diffusion coefficient, the shear thinning characteristics and the yield stress properties of the displaced fluid contribute to an increase in instability. Furthermore, the thermal parameters positively influence the rate of Brownian motion exhibited by the nanoparticles.

Research and Application of Drilling Fluid Cooling System for Dry Hot Rock

The drilling fluid cooling system is a key technology for reducing wellbore temperatures, improving the working environment of downhole equipment, and ensuring safe and efficient drilling in high-temperature wells. Based on the existing drilling fluid cooling system, this article designs and develops a closed drilling fluid cooling system according to the working environment and cooling requirements of the GH-02 dry hot rock trial production well in the Gonghe Basin, Qinghai Province. The system mainly includes a cascade cooling module, a convective heat exchange module, and a monitoring and control module. Based on the formation conditions and drilling design of the GH-02 well, a transient temperature prediction model for wellbore circulation is established to provide a basis for the design of the cooling system. Under the conditions of a drilling fluid displacement of 30 L/s and a bottomhole circulation temperature not exceeding 105 °C, the maximum allowable inlet temperature of the drilling fluid is 55.6 °C, and the outlet temperature of the drilling fluid is 69.2 °C. The heat exchange of the drilling fluid circulation is not less than 1785 kW. Considering the heat transfer efficiency and reserve coefficient, the heat transfer area of the spiral plate heat exchanger calculated using the average temperature difference method is not less than 75 m2. By applying this drilling fluid cooling system in the 3055 m~4013 m section of well GH-02, the inlet temperature is controlled at 45 °C~55 °C, and the measured bottomhole circulation temperature remains below 105 °C. After adopting the drilling fluid cooling system, the performance of the drilling fluid is stable during the drilling process, downhole tools such as the drill bits, screws, and MWD work normally, and the failure rate of the mud pump and logging instruments is significantly reduced. The drilling fluid cooling system effectively maintains the safe and efficient operation of the drilling system, which has been promoted and applied in shale oil wells in Dagang Oilfield.