岩性波阻抗正演模拟差异方法储层预测中的应用

当地层中存在过渡岩性(粉砂质泥岩、泥质粉砂岩)时,各种岩性之间形成波阻抗差,造成了实际地震资料中的同向轴不是砂、泥岩之间的分界面,而是多种岩性共同影响的结果,从而影响地震资料对砂岩储层的预测能力,降低了储层预测的可信度.利用测井解释成果得到岩性波阻抗曲线,通过岩性波阻抗曲线和测井波阻抗曲线与空变子波分别进行三维正演模拟.将2种不同正演结果进行对比分析,确定二者之间的差异并利用其确定过渡岩性影响的区域和范围,通过处理和计算屏蔽过渡岩性在地震资料中的影响,得到高可信度的地震资料;然后通过分区分时窗提取地震属性,预测储层的分布特征及范围.应用该方法提高了储层预测可信程度,改善了储层预测效果.     

Features of Capacitance and Mobility of Injected Carriers in Organic Layers Measured by Impedance Spectroscopy

Transport of charge carriers in organic layers plays a relevant role in the performance of electronic devices such as light-emitting diodes, solar cells, and photodetectors. The presence of energetically distributed traps severely affects the measured transport coefficient and the charge-storage features in the film. We summarize recent theoretical work on impedance spectroscopy models for space–charge limited current of a single carrier in a multiple trapping model, which describes the experimental behavior usually observed in organic layers with injected charge carriers well. Two main physical effects are obtained from the numerical and analytical treatment. First, carriers in slow traps that do not follow alternating current modulation provide an increase in the capacitance at low frequency, and second, those in fast traps remain in equilibrium with the transport state increasing the transit time. Analysis also provides a unified interpretation of models with field- or carrier-density dependence on mobility.     

Study on Power Fluctuation Dispatch and Capacity Design of Short Period Power Fluctuation Compensation System in Consideration of Power Loss

Since the output of photovoltaic (PV) generation includes power fluctuations caused by natural conditions, the installation of PV on a large scale is expected to affect load frequency control of the power grid. One method of compensating power fluctuations is the use of energy storage (ES), such as batteries and capacitors. A power fluctuation compensation system composed of an electrical double layer capacitor energy storage system (ESS) and a Li‐ion battery energy storage system is considered. The power loss characteristics of both ESSs during power fluctuation compensation are modeled by equivalent circuits based on ES impedance spectra. The models are validated by experiments simulating power fluctuation compensation. Using these ES models, simulations were carried out to determine the power fluctuation dispatch method between the two ESSs and the capacity of the ESSs in consideration of power loss minimization.     

Microstructure and corrosion behaviour of plain carbon steel–B4C composite produced by GTAW method in 3·5 wt-%NaCl solution

In this work, the corrosion behaviour of metal matrix composite plain carbon steel–B₄C was studied in 3·5 wt-%NaCl solution. The composite was locally produced as weld band on plain carbon steel by means of gas tungsten arc welding process and using nickel as wetting agent. Samples from weld band, heat affected zone and base regions were extracted precisely, and electrochemical techniques including open circuit potential, linear polarisation resistance, electrochemical impedance spectroscopy, potentiodynamic polarisation in combination with SEM-EDX surface analysis and microhardness were used for characterisation. The results showed that hardness value of made composite increased significantly to 642 HV10. However, the corrosion resistance of composite region during 7 days (168 h) of exposure to 3·5 wt-%NaCl solution was slightly reduced. This was attributed to the fact that B₄C particles play as cathode site for oxygen reduction; therefore, they increase the corrosion rate slightly.     

New experimental evidence on the formation of platinum superactive sites in an electrochemical environment

New electrochemical results are found after the application of a constant cathodic polarization to the platinum/aqueous acid solution interface within the hydrogen evolution region. Voltammograms reveal highly stable anodic peaks emerging in the double-layer region assigned to the so-called “superactive” states. The severe cathodization produces the disruption of the platinum/aqueous solution interface leading to an open outer layer composed of metallic species highly coordinated to the solvent. These active sites are related with electrocatalytic features since the onset potential for water discharge is diminished. Voltammetry and modulated voltammetry explain the fact that platinum species highly coordinated to the solvent can be more oxidized since the reduction potential shifts toward more negative values. The alkalinization of the interface and the formation of new surface oxides in a different potential range are proposed. The latter produces electrocatalytic effects on methanol electrooxidation.     

Synthesis and electrochemical performance of La0.6Ca0.4Fe1−xNixO3 (x = 0.1, 0.2, 0.3) material for solid oxide fuel cell cathode

Polycrystalline samples of La_0.6Ca_0.4Fe_1−xNi_xO₃ (x = 0.1, 0.2, 0.3) (LCFN) are prepared by liquid mix method. The structure of the polycrystalline powders is analyzed with X-ray powder diffraction data. The XRD patterns are indexed as the orthoferrite similar to that of LaFeO₃ having a single phase with orthorhombic perovskite structure (Pnma). The morphological characterization is performed by scanning electron microscopy (SEM) obtaining a mean particle size less than 300 nm.Polarization resistance is studied using two different electrolytes: Y-stabilized zirconia (YSZ) and Sm-doped ceria (SDC). Electrochemical impedance spectroscopy (EIS) measurements of LCFN/YSZ/LCFN and LCFN/SDC/LCFN test cells are carried out. These electrochemical experiments are performed at equilibrium from 850 °C to room temperature, under both zero dc current intensity and air. The best value of area specific resistance (ASR) obtained is 0.88 Ω cm², corresponding to the La_0.6Ca_0.4Fe_0.9Ni_0.1O₃ material using SDC as electrolyte. The dc four-probe measurement indicates that La_0.6Ca_0.4Fe_0.9Ni_0.1O₃ exhibits fairly high electrical conductivity, over 300 S cm⁻¹ at T > 500 °C.     

Corrosion monitoring of hydrogen by HUP probe in the presence of sulphide and thiourea

The effect of sulphide and thiourea on hydrogen uptake during the corrosion of steel in deaerated pH3 has been studied using an electrochemical hydrogen probe incorporating a solid electrolyte (HUP) and lead dioxide (PbO₂) as a reference electrode. This probe has been used for the quantitative determination of the hydrogen activity generated during the corrosion of steel. The sensor voltage implies an average equivalent hydrogen pressure in uncharged steel of 2 × 10^?18 atmospheres. During the corrosion of steel, this value increases by very large amounts; thus in deaerated pH3, the equivalent pressure rose by 10^24.5 in the presence of 200 ppm sulphide and by 10² in the presence of 100 ppm thiourea. Weight loss and AC impedance methods were also performed under the same conditions as the hydrogen measurements. The hydrogen probe data were correlated with a.c impedance and weight loss results in order to understand the effect of S^2? and thiourea on hydrogen uptake.     

Effect of pyrophyllite additions on sintering characteristics of fly ash based ceramic wall tiles

Abstract

The sintering characteristics of fly ash-pyrophyllite mixes containing 0-100 wt-% sericitic pyrophyllite have been studied, using 10 wt-% sodium hexametaphosphate as a binding agent and a firing temperature of 950°C. Increasing pyrophyllite content has been observed to increase the impact strength and apparent density and decrease the water absorption of sintered tile samples. Moreover, the presence of pyrophyllite imparted improved thermal shock resistance to the wall tile samples.     

The inhibitive effect of 5‐amino‐indole on the corrosion of mild steel in acidic media

The inhibitor performance of 5‐aminoindole (5‐AI) on mild steel corrosion in 0.5 M HCl was investigated in relation to the inhibitor concentration using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and linear polarization (LPR) methods. The effect of immersion time on the corrosion behavior of mild steel was also studied. The impedance data obtained were fitted and modeled using an equivalent circuit model. The results show that 5‐AI is an effective inhibitor and has an inhibition efficiency of 90% at 1 × 10^?2 M additive concentration. The adsorption behavior of 5‐AI was also investigated. For this purpose, the adsorption equilibrium constant (K_ads), and the free energy of adsorption (ΔG_ads) were calculated and discussed. It was found that 5‐AI acts as mixed‐type inhibitor and obeys Langmuir adsorption isotherm with a free energy of adsorption of ?27.71 kJ/mol.     

Long term assessment of a hybrid electrochemical treatment

Monitoring the performance of systems installed to protect against/halt the corrosion of reinforcing steel in concrete is essential in ensuring that the reinforcing bar (rebar) is adequately protected and remains in a non‐corroding state. A chloride contaminated concrete test block containing a hybrid anode system has been periodically monitored over the past 4.5 years to assess the anode current output and thus, the protection offered to the steel. De‐polarisation and impedance analysis data have been acquired to calculate steel corrosion rates. Both tests indicated that the steel was passive in the concrete environment and that the anode was able to protect all of the embedded steel despite the difficult geometry of the sample. It was also found that after 2 years it was still possible to drive a high current from the installed anode.