Hasil untuk "Oils, fats, and waxes"

Lennart Obster

We discuss a new point of view of representation theory of Lie groupoids and algebroids: fat Lie theory. The category of fat extensions is introduced, as well as the category of abstract $2$-term representations up to homotopy (ruths) -- the intrinsic objects behind usual (split) $2$-term ruths. We obtain a one-to-one correspondence between them, and relate to the well-known equivalence between $2$-term ruths and VB-groupoids/algebroids. On the other hand, we show that fat extensions of groupoids correspond to general linear PB-groupoids. The differentiation procedure of fat extensions is discussed, as well as the functorial aspects of all mentioned correspondences. In particular, we upgrade the one-to-one correspondence between general linear PB-groupoids and VB-groupoids of Cattafi and Garmendia to an equivalence of categories. Fat extensions are intimately related to another notion we introduce: core extensions. We show that they correspond to vertically/horizontally core-transitive double groupoids, generalising work by Brown, Jotz-Lean and Mackenzie. This way, we also realise regular fat extensions as general linear double groupoids.

Yifan Li, Jesus M. Marcos, Mark Fasano et al.

Oil and water placed atop of a solid surface respond differently to a MHz-level surface acoustic wave (SAW) propagating in the solid due to their different surface wetting properties. We observe that, under SAW excitation, oil films, whether non-organic silicon oil or organic sunflower oil, are extracted continuously from sessile drops, comprising emulsions of the oil in question in a solution of water and surfactants. The mechanism responsible for the extraction of oil from the mixtures is the acoustowetting phenomenon: the low surface tension oil phase leaves the mixture in the form of 'fingers' that, away from the drop, spread opposite the path of the SAW. The high surface tension water phase remains at rest. Increasing either the SAW intensity or the oil content in the mixture enhances the rate at which oil leaves the emulsion. We further observe acoustic-capillary flow instabilities at the free surface of the oil film and the formation of spatial gradients in the emulsion oil-concentrations in the presence of SAW. Our study suggests the potential for using SAW for heterogeneous removal of oil from oil-in-water mixtures to complement current phase separation methods.

Renée-Claude Bider, Cristian Ciobanu, Jorge Campos Pazmiño et al.

Purpose: To improve on the original form of Fat DESPOT, a multiparametric mapping technique that returns the fat- and water-specific estimates of $R_1$ ($R_{1f}$, $R_{1w}$), $R_2^*$ , and proton density fat fraction (PDFF) by upgrading the fat-water separation method used for selection of initial parameter guesses, and by introducing explicit model sensitivity to the phase of the water and fat signals. Methods: We compared the 3-point Dixon and Graph Cut (GC) approaches to initial guesses for Fat DESPOT in phantom experiments at 3 T in a variable fat fraction gel phantom. Also in phantom, we then compared the original Fat DESPOT approach to a magnitude approach modelling the phases of fat and water separately (Fat DESPOT$_{mφ}$), and an approach that models the complex data (Fat DESPOT$_c$). The best-performing approach was then used in the lower leg of a healthy human participant. Results: In phantoms, Fat DESPOT using the 3-point Dixon and GC performed similarly in parametric estimates and precision, though the Dixon approach deviated from the overall trend in the 50% nominal fat fraction ROI. Furthermore, Fat DESPOT$_c$ showed the best agreement with reference PDFF (average error 1.5 +/- 1.2%) and the lowest combined standard deviation across ROIs, for PDFF, $R_{1f}$, and $R_{1w}$ (σ = 0.13%, 0.19 s$^{-1}$, 0.0082 s$^{-1}$). Conclusion: With a higher precision of $R_{1f}$ and $R_{1w}$ , accuracy of PDFF, and more echo time versatility than other compared approaches, this work demonstrates the advantages of the GC approach for initial guesses paired with complex fitting for Fat DESPOT multiparametric imaging.

A. C. Alvarez, H. Bruining, D. Marchesin

Low salinity waterflooding (LSWF) enhances oil recovery at low cost in carbonate reservoirs, but its effectiveness requires precise control of injected water chemistry and interaction with reservoir minerals. This study develops an integrated reactive transport model coupling geochemical surface complexation modeling (SCM) with multiphase compositional dynamics to quantify wettability alteration during LSWF. The framework combines PHREEQC-based equilibrium calculations of the Total Bond Product (TBP), a wettability indicator derived from oil-calcite ionic bridging, with Corey-type relative permeability interpolation, resolved via COMSOL Multiphysics. Core flooding simulations, compared with experimental data from calcite systems at 100 degrees Celsius and 220 bar, reveal that magnesium and sulfate concentrations modulate TBP, reducing oil-rock adhesion under controlled low-salinity conditions. Parametric analysis demonstrates that acidic crude oils (TAN higher than 1 mg KOH per gram) exhibit TBP values approximately 2.5 times higher than sweet crudes, due to carboxylate-calcite bridging, while pH elevation (above 7.5) amplifies wettability shifts by promoting deprotonated carboxyl interactions. The model further identifies synergistic effects between magnesium (50 to 200 millimoles per kilogram of water) and sulfate (above 500 millimoles per kilogram of water), which reduce calcium-mediated oil adhesion through competitive mineral surface binding. By correlating TBP with fractional flow dynamics, this framework could support the optimization of injection strategies in carbonate reservoirs, suggesting that ion-specific adjustments are more effective than bulk salinity reduction.

Tom de Jong, Nicolai Kraus, Simona Paoli et al.

Motivated by the study of weak identity structures in higher category theory we explore the fat Delta category, a modification of the simplex category introduced by J. Kock. We provide a comprehensive study of fat Delta via the theory of monads with arities, and use these results to show that fat Delta is a hypermoment category in the sense of C. Berger. Specifically, by proving that the free relative semicategory monad is strongly cartesian and identifying a dense generator, the theory of monads with arities immediately gives rise to the nerve theorem. We characterise the essential image of the nerve via the Segal condition, and show that fat Delta possesses an active-inert factorisation system. Building on these results, we also establish an isomorphism between two presentations of fat Delta and show that it is a strongly unital and extensional hypermoment category.

Sergey Parnovsky, A. A. Varlamov

Olive oil is an integral part of Mediterranean culture, shaped by more than three thousand years of history, rich traditions, evolving technologies, and fundamental physical principles. This article explores the role of physics in the production of olive oil, highlighting how physical laws govern each stage of the process.

Ju Yafeng, Liu Yuwan, Zhang Hui et al.

The reservoirs in Changqing Oilfield are typically low porosity and low permeability， making conventional perforation operations impossible to effectively improve the near wellbore permeability required for water injection. Based on the principle of impact dynamics， together with the distribution characteristics of perforation compaction zones， a numerical calculation model for reservoir damage by composite perforation was built， and the evaluation indexes of reservoir damage by composite perforation were proposed. The distribution characteristics of fracture zones formed by composite perforation were explained， and the influences of perforation parameters （perforation density， phase angle） and formation properties （in-situ stress， rock strength） on reservoir damage by composite perforation were revealed. The study results show that the larger the perforation density， the larger the fracture area formed near the wellbore. When the phase angle is small， there is a better effect of penetrating the compaction zone near the wellbore. When the phase angle is large， a larger penetration depth can be formed for the compaction zone at the end of the channel. When the in-situ stress and rock strength are small， the axial and radial blockage removal effects of the compaction zone are better. The calculation and analysis of case wells show that the composite perforation can realize blockage removal of compaction zone near the wellbore and the end of the channel， and effectively realize the connection between the perforation channel and the reservoir. The reason for under injection may be low reservoir permeability and severe pore filling. It is proposed to adopt a super-energy perforation-alternating injection acid fracturing combined operation mode in target wells to improve injection conditions. The study results have reference significance for the stimulation response evaluation of composite perforation and the optimization of perforation parameters.

Zhizhi Zhou, Jiahuan Jiang, Yuanyuan Sun et al.

In this study, we successfully developed two-dimensional paper-based analytical devices using a hybrid technique of injection molding and embossing. This innovative approach involves passive or active delivery of molten wax onto a glass substrate through a sealed chip, facilitating wax stamp creation.

Osiris Jorge Parcero, Elissaios Papyrakis

Surprisingly, there has been little research conducted about the cross-country relationship between oil dependence/abundance and income inequality. At the same time, there is some tentative evidence suggesting that oil rich nations tend to under-report data on income inequality, which can potentially influence the estimated empirical relationships between oil richness and income inequality. In this paper we contribute to the literature in a twofold manner. First, we explore in depth the empirical relationship between oil and income inequality by making use of the Standardized World Income Inequality Database; the most comprehensive dataset on income inequality providing comparable data for the broadest set of country-year observations. Second, this is the first study to our knowledge that adopts an empirical framework to examine whether oil rich nations tend to under-report data on income inequality and the possible implications thereof. We make use of Heckman selection models to validate the tendency of oil rich countries to under-report and correct for the bias that might arise as a result of this; we find that oil is associated with lower income inequality with the exception of the very oil-rich economies.

XUE Gang,GUO Tao,ZHANG Ye,XU Xiangyang,WANG Wei,HAN Kening,GUO Dongxin,JIN Xiaobo

The exploration and development of coalbed methane（CBM）in the Permian Longtan Formation in south Chongqing is in the initial stage. In order to reveal the general geological conditions of coalbed methane in the coal seam C25, by the experimental and geological data obtained from the coal mines and coalbed methane drilling, the geological characteristics such as coal rock and coal quality, coal pore penetration and gas content have been analyzed. The results show that the C25 coalbed methane of Longtan Formation of Permian in the study area is characterized by “stable development, relatively large thickness, low pore permeability, high metamorphism and high gas content”. The development of the coal seam C25 is stable throughout the whole area, showing the trend of “thick in the north and thin in the south”, and the thickness in the northern part of the coalbed is generally larger than 1.5 m. The coal quality belongs to semi-bright coal. The content of vitrinite in the organic component is 51.7%~72.2%; the vitrinite reflectance ranges from 1.8%~2.2%, and the metamorphism degree is high-over maturity. The porosity and permeability of the coal rock are relatively low, with the porosity ranging from 3.46%~8.46% and the permeability of mostly lower than 0.01×10-3 μm2. The gas content of the coal bed is high, generally more than 10.0 m3/t; meanwhile, the top and bottom plates of the coal bed are good sealing layers. Based on the production of Q1 and Y2, it is believed that the coal seam C25 of Permian Longtan Formation in south Chongqing area has good geological conditions for CBM exploration and development.

WANG Xiang, ZHANG Guicai, JIANG Ping et al.

The volume sweep coefficient is essential for evaluating the development effect and formulating development adjustment plans for oil fields. This paper aims to study the variation law of volume sweep coefficient in different stages of water injection development. From the perspective of the injection pore volume multiple， a calculation model is built of displacement efficiency and injection pore volume multiple， and a calculation method of volume sweep coefficient is proposed based on oil-water relative flow theory and reservoir engineering principle. In addition， three test areas of Shengli Oilfield are taken as examples for calculation and analysis. The results show that the relationship between the displacement efficiency and the injection pore volume multiple satisfies an exponential equation， and the relationship curve between the two is upward convex. As the injection pore volume multiple increases， the displacement efficiency gradually increases from the minimum displacement efficiency and approaches the maximum displacement efficiency. The displacement efficiency calculation model is verified， and the average relative error between the predicted and measured values is only 1.90%. During the water flooding development， the relationship curve between the volume sweep coefficient and the injection pore volume multiple shows an evolution trend of fast rising， slow rising， and near platform. The calculation results can guide the effect evaluation of development adjustment measures. At present， the volume sweep coefficient of the three test areas is about 90%. There is a large amount of remaining oil in the swept area. It is urgent to study the description and start-up method of the main remaining oil in the swept area.

Mohamed Hosin ElNeiri, Abdel Sattar Abdel Hamid Dahab, Abdulaziz Mohamed Abdulaziz et al.

The application of laser in the drilling and perforation of oil wells can achieve great benefits such as reduced drilling costs and time with a higher rate of penetration (ROP) and elimination of casing necessity in oil and gas well drilling. This paper presents an original experimental investigation of Laser cutting through Hashma sandstone (a common quarry rock in Egypt) to develop a good understanding of the laser cutting process in sandstone. Five blocks of Hashma sandstone with dimensions of 35 cm × 35 cm × 10 cm were utilized to study the effects of the various parameters involved in the lasing (cutting) process in order to evaluate the cutting process through sandstone, investigate the effect of laser parameters on the process and the cutting mechanisms. The experimental results showed that the laser drilling can provide lower specific energy (SE) compared to conventional drilling methods, revealed the effect of various laser and rock parameters (such as beam power, intensity, duration, sample size, and orientation) on the cutting process, and demonstrated the laser cutting mechanisms through sandstone such as thermal spallation and melting mechanisms. Several parameters must be optimized for an optimum laser cutting process with the lowest SE, such as using the optimum beam power, beam duration (or Lasig time), and beam mode (continuous or pulsed). The optimum parameters may change from one case to another and depend on the overall interactions among the various variables such as thermal dissipation rate and purging system efficiency.

Farad Kamyabi, Arif Mammad-Zade

Enhancing oil recovery from clayey reservoirs is a significant challenge in petroleum industry due to complex interactions between fluids and rock surfaces, particularly clay swelling. This study presents the first empirical analysis of magnetic fields' impact on fluid flow in clayey porous media. Our core findings indicate that magnetic treatment of water increases oil recovery by an average of 15–30% in clayey media, with limited effectiveness in pure quartz media. Detailed experiments unraveled that improved recovery factor by magnetic treatment stem from both mitigated swelling and altered magnetic properties at clay surface; introducing 30% clay to porous medium decreased the recovery by 32% compared to pure quartz sand. Heating the clay to around 1000 °C to reduce its swelling property improved the recovery by only 16%, suggesting magnetic treatment is not solely attributed to clay swelling mitigation. Treating ferromagnetic films at clay surface with HCl to produce non-magnetic FeCl3 resulted in a high recovery factor, similar to the clay-free medium. Moreover, it was determined that a magnetic field intensity of 43760–51740 A/m is optimal for fluid displacement in clayey media. Notably, the intensity of 47760 A/m increased recovery to 84.5% in a 30% clay medium, compared to 49.7% without treatment. Interestingly, it was observed that the maximum flow rate was associated with zero potential difference across the medium, providing a faster method to determine the optimum magnetic field intensity. Lastly, the concept of ‘Magnetic memory’ was investigated, referring to the persistence of magnetic field's influence after its removal. Our findings indicated that pressure build-up time stability lasted 10 days post-treatment, after which water behavior reverts, and clay swelling resumes. This insight into the temporal dynamics of magnetic field application provides a deeper understanding of its long-term impacts on fluid flow in clayey reservoirs.

Tang Yuqiang, Feng Jin, Xia Qi et al.

In order to solve the scaling problem of downhole pump in oilfield development, the corrugated plate was used as the scaling component of pre-scaling device in front of the pump, and its scaling law was analyzed.Based on the Kern-Seaton scaling rate model, a semiempirical formula for scale deposition was derived.Then, the turbulence-chemical interaction model and DPM model were used to simulate the scaling process of CaCO₃ particles on the surface of corrugated plate in pipeline, and quantitatively analyze the influence of temperature, flow rate and particle mass concentration multiple on the scaling rate.Finally, the downhole produced fluid was prepared for laboratory scaling experiment.The results show that there is a good consistency between numerical simulation and laboratory experiment.The increase in temperature and particle mass concentration promotes the scale deposition of calcium carbonate, while the increase in flow rate inhibits the scale deposition of calcium carbonate.In the actual production process, the temperature and concentration of scale-forming ions in the well are uncontrollable.Therefore, the scaling of downhole pump can be alleviated by appropriately reduce the flow rate of produced fluid and thus increase the amount of scale buildup on the surface of the corrugated plate.The conclusions provide theoretical basis and new ideas for scale prevention and removal in oilfields.

Mohammad Rostamtabar, Mohammad Khanehbad, Asadollah Mahboubi et al.

The Fahliyan Formation, a significant carbonate reservoir in southwestern Iran encompassing the Izeh and Dezful Zones, underwent detailed petrographic investigations. These analyses revealed eight distinct microfacies associated with four different depositional settings within a homoclinal ramp model. From a diagenesis perspective, the formation has undergone various processes, including micritization, dissolution, compaction, cementation, dolomitization, stylolitization, and fracturing. These diagenetic features affected the Fahliyan Formation from early marine–meteoric to late burial diagenetic realms. Notably, dissolution developed as the most effective and widespread diagenetic feature, improving reservoir quality. Likewise, fracture and dolomitization positively impact reservoir quality, while compaction and cementation have destructive effects. Micritization and early isopachous calcite cement have a retentive role in reservoir characteristics. In addition, the Flow Zone Indicator (FZI) approach introduced three Hydraulic Flow Units (HFUs). The correlation between microfacies types and their petrophysical features indicates that the bioclastic peloid packstones and grainstones have better reservoir quality, which resulted from dissolution, and initial isopachous calcite cements. Also, Planktonic foraminifer’s bioclastic mud/ wackestone and Quartz-bearing mudstone, equivalent to HFU1, indicate lower reservoir quality due to the compaction (stylolitization) and cementation.

CHEN Hongzhi, LU Junqiang, JU Xiaodong et al.

Acoustic-type logging instruments generate high voltages in the order of thousands of volts. Electromagnetic interferences are thus induced by high-voltage pulses that affect the logging tool and make it inoperable owing to damaged components in severe cases. In particular, weak acoustoelectric signals, vulnerability to electro magnetic interference, and other characteristics require higher electro magnetic compatibility of the acoustoelectric logging detector. The system’s complexity makes it difficult to find and analyze the root cause of the interference. This paper revolves around the three elements of electromagnetic compatibility. The electrode measurement circuit is a sensitive source. Through interference analysis and testing, the high voltage pulse source is determined to be the source of interference. We focus on analyzing the formation mechanism of electromagnetic interference coupling paths. The electromagnetic interference characteristics of the detector are systematically analyzed and verified by combining the qualitative electric coupling mechanism, the quantitative Gaussian electric field law and the electric coupling experimental study. This paper reduces the main interference causes and characteristics of the detector and reveals that the electrical coupling of high voltage pulses is the main interference cause of the acoustoelectric logging detector. The method to eliminate the coupling path is proposed.

Leonardo F. Cavenaghi, Lino Grama

This paper delves into the concept of ``fat bundles'' within Riemannian submersions. One explores the structural implications of fat Riemannian submersions, particularly focusing on those with non-negative sectional curvature. The main results include the classification of fibers as symmetric spaces, the isometric correspondence of fat foliations with coset foliations on Lie groups, and the rigidity of dual foliations associated with fat Riemannian submersions.

Debjani Phani, Rajasekhar Konduru Varadarajulu, Arijit Paramanick et al.

Purpose: To develop and validate a phantom for diagnostic ultrasound (US) scanners by embedding targets in gel wax to determine the image uniformity, lateral and axial resolution, and diameter of a stainless-steel disc. Materials and Methods: Acoustic property (AP), which includes the velocity of US (cus), acoustic impedance (Z), and attenuation coefficient in gel wax were determined. The cus, and attenuation coefficient were estimated using the pulse-echo technique. Z was obtained from the product of sample density (\r{ho}) and cus. Two rectangular frames using polytetrafluoroethylene (PTFE) sheets with holes separated by 5, 10, and 20 mm distances were constructed. Nylon filaments and SS-disc (diameter = 16.8 mm) were threaded through the frames and suitably placed in melted gel wax to obtain orthogonal targets. The targets were measured using computerized tomography (CT) and a 2-9 MHz US probe. Results: The AP of gel wax were cus=1418 m/s, \r{ho}= 0.87 g/cm3, Z=1.23 MRayls, attenuation coefficient= 0.88 dB/cm/MHz. The results of US imaging of the targets were compared with their physical sizes and served as baselines for the scanner and probe. The maximum error in distance measurement in the phantom US images was 7.1%, and the phantom volume decreased by 1.8% over 62 weeks. Conclusion: Gel wax can be useful in developing affordable, highly stable, and customizable diagnostic US phantoms that can be implemented widely.

Michael Daly, Bernard Auchmann, André Brem et al.

Resin-impregnated high-field Nb3Sn type of accelerator magnets are known to require extensive training campaigns and even may exhibit performance-limiting defects after thermal or electromagnetic cycling. In order to efficiently explore technological solutions for this behaviour and assess a wide variety of impregnation material combinations and surface treatments, the BOnding eXperiment (BOX) sample was developed. BOX provides a short-sample test platform featuring magnet-relevant Lorentz forces and exhibits associated training. Here we report on the comparative behaviour of BOX samples comprising the same Nb3Sn Rutherford cable but impregnated either with common resins used in high-field magnets, or with less conventional paraffin wax. Remarkably, the two paraffin wax-impregnated BOX samples reached their critical current without training and are also resilient to thermal and mechanical cycling. These rather encouraging results strongly contrast to those obtained with resin impregnated samples, which show the characteristic extensive training and at best barely reach their critical current value.

HUANG Ya'nan, HOU Lei, XIAO Kaixi et al.

To explore the demulsification mechanism of emulsion under electric fields, the movement process of dispersed phase droplets in water-in-oil emulsion was simulated with the finite element method. Herein, the oil-water distribution was represented with the phase field method, and the accuracy and efficiency of calculation on fluid flow process was improved with the structured quadrilateral grid. Besides, the influence laws of electric field parameters, as well as the physical parameters of emulsion, on the droplet deformation and coalescence were systematically studied to provide theoretical basis for the efficient application of electric demulsification technology. According to the results, the higher the electric field intensity, root mean square(RMS) of electric field waveform and droplet size, the greater the deformability and coalescence ability of droplets are. The droplet deformation is independent of frequency under the high-frequency conditions, and the frequency has little effect on the coalescence rate of droplets. Meanwhile, the droplet deformation and coalescence rate can been improved by decreasing the continuous phase viscosity and oil-water interfacial tension. In addition, the microcosmic mechanism of droplet deformation and coalescence was also discussed. It is found that the maximum droplet deformation is in strong linear relationship with the electric Weber number in the case of small deformation, and the electric field intensity,droplet size and interfacial tension affect the coalescence efficiency of droplets by influencing the evolution of liquid bridge between droplets.