Effects of magnetic field on calcium carbonate precipitation: Ionic and particle mechanisms

There are two most widely reported mechanisms to study the effect of magnetic fields on calcium carbonate (CaCO₃) precipitate, namely ionic and particle mechanisms. The effects are most debatable because they are contrary to each other. This study explored the effects of both mechanisms in CaCO₃ deposit and total CaCO₃ precipitation using ionic and particle methods. The ionic method showed reductions in CaCO₃ deposit and total precipitation rate of CaCO₃, whereas the particle method showed the opposite results. The particle number decreased and the average particle diameter of CaCO₃ deposit increased in the ionic method. Meanwhile in the particle method, the particle number increased, average particle diameter decreased and particle aggregation of CaCO₃ was observed. XRD measurement on all deposits showed that the crystal deposit was mostly of calcite and the traces of vaterite. However, the amount of the crystal in the particle method was observed to be less than that in the ionic method, indicating that CaCO₃ deposit was more amorphous. Particle mechanism decreased the Ca²⁺ ion concentration in solution during magnetization, and ionic mechanism reduced scale (CaCO₃) formation after magnetization and separation processes. This method could be applied for decreasing water hardness and prevent the formation of scaling.     

塔中BZ井区碳酸盐岩非均质储层叠前精细预测技术

塔中BZ井区上奥陶统良里塔格组礁滩体储集层是油气勘探重要目的层之一,其特点是埋藏深,储集层基质孔渗低,储集空间多为构造裂缝及溶蚀作用所产生的孔、缝、洞系统,储集体受多种因素控制,纵横向非均质性强,叠后声阻抗反演技术和常规叠后地震属性分析技术难以有效预测该类储层。因此有必要开展叠前弹性波阻抗反演研究。给出了叠前弹性波阻抗反演技术的主要实现方法、步骤,比较了利用弹性波阻抗反演技术与常规叠后声阻抗反演技术预测上奥陶统良里塔格组礁滩体储层实际应用效果。结果表明弹性参数预测储层分辨率高,能够反映碳酸盐岩储层非均质性分布特征,与实际的钻探成果具有较好的一致性,该方法对塔中地区下一步碳酸盐岩油气勘探具有一定的参考意义。     

Pre-stack inversion for caved carbonate reservoir prediction: A case study from Tarim Basin, China

The major storage space types in the carbonate reservoir in the Ordovician in the TZ45 area are secondary dissolution caves.For the prediction of caved carbonate reservoir,post-stack methods are commonly used in the oilfield at present since pre-stack inversion is always limited by poor seismic data quality and insufficient logging data.In this paper,based on amplitude preserved seismic data processing and rock-physics analysis,pre-stack inversion is employed to predict the caved carbonate reservoir in TZ45 area by seriously controlling the quality of inversion procedures.These procedures mainly include angle-gather conversion,partial stack,wavelet estimation,low-frequency model building and inversion residual analysis.The amplitude-preserved data processing method can achieve high quality data based on the principle that they are very consistent with the synthetics.Besides,the foundation of pre-stack inversion and reservoir prediction criterion can be established by the connection between reservoir property and seismic reflection through rock-physics analysis.Finally,the inversion result is consistent with drilling wells in most cases.It is concluded that integrated with amplitude-preserved processing and rock-physics,pre-stack inversion can be effectively applied in the caved carbonate reservoir prediction.     

Effect of nickel oxide synthesis conditions on its physical properties and electrocatalytic oxidation of methanol

Nickel oxide (NiO) was synthesized using several methods and the various physical characteristics observed were correlated to differences in electrocatalytic activity, specifically relating to the oxidation of methanol in alkaline media. Room temperature NaOH-precipitated NiO showed the highest activity and stability towards methanol oxidation in hydroxide (0.005 M KOH) and carbonate (0.1 M Na₂CO₃) media of similar alkalinity. Rapid degradation of NiO electrodes was attributed to microcracking and disintegration associated with the formation of the γ-NiOOH/α-Ni(OH)₂ redox couple, in addition to repeated scans through the oxygen evolution reaction region. Carbonate electrolytes also exhibited average current ranges 3–4 times higher and charge transfer resistances around 85% lower than hydroxide electrolytes. This suggests carbonate may provide a better medium in terms of higher activity and more moderate alkalinity for electrochemical reactions than hydroxide solutions.     

流体包裹体分析在划分碳酸盐胶结物形成期次中的应用

通过对北京西山露头剖面寒武系和奥陶系岩石裂缝中碳酸盐胶结物中的流体包裹体进行分析,结合地质分析,重点研究了流体包裹体在划分碳酸盐胶结物形成期次中的应用。研究表明,研究区发育的流体包裹体主要为盐水包裹体;包裹体均一温度集中分布在94～98℃和133～145℃这2个区间,相应的盐度区间为4%～8.9%和11.9%～12.5%;碳酸盐胶结物的形成可以分为2期,即Ⅰ期和Ⅱ期,形成深度为1 975～2 075 m和2 950～3 250 m,分别对应于中侏罗世-早白垩世和古近纪,均形成于对流带上部。     

Hydrochemical investigation on the clastic and carbonate aquifers of Kuwait

The field pH and contents of basic cations, anions, total alkalinity and other aqueous species have been measured in 89 groundwater samples collected from clastic sediments and carbonate aquifers of Kuwait. The mean molar ratio of Mg²⁺/Ca²⁺ is 0.63 and 0.48 for the carbonate and clastic aquifers respectively, indicating that the groundwater of the carbonate aquifer is in equilibrium with calcite and dolomite, the calculated mean PCO₂ of the clastic and carbonate aquifers suggesting a deep closed environment system. The clastic aquifer is supersaturated with respect to calcite, aragonite, quartz and chalcedony, undersaturated to near-saturated with dolomite and undersaturated with respect to gypsum, anhydrite and halite, whereas the carbonate aquifer is supersaturated with respect to dolomite, calcite, aragonite and quartz but undersaturated with anhydrite, gypsum and halite. The salinity of both aquifers increases in the direction of flow. The water types are dominantly NaCl and Na₂SO₄ in the clastic aquifer and Na₂SO₄, CaSO₄ and NaCl in the carbonate aquifer. Electronic Publication     

Characterization of Poly(Aminosiloxane) Surface Chemistry on Aluminum Oxide

N-2-aminoethyl-3-aminopropyltrimethoxysilane (AAPS) was shown to react with aluminum oxide powder to form an amine/carbonate salt, as observed by diffuse reflectance infrared spectroscopy (DRIFT) and thermogravimetric analysis with mass spectroscopy (TGA-MS). TGA-MS, together with electron spectroscopy for chemical analysis (ESCA), reveal that the stoichiometric ratio of amine salt to free amine is higher on the surface of aluminum oxide powder than in a comparable neat film. In addition, TGA-MS shows that a nonstoichiometric ratio of CO₂H₂O is evolved upon heating the surface-treated powder (4.5/1), whereas the neat film evolves CO₂/H₂O at a ratio near unity. The high fraction of protonated amines, together with the higher ratio of CO₂/H₂O in the presence of alumina, is consistent with a proposed bonding mechanism which involves carbonate bridging between protonated amines and hydroxyl sites on the aluminum oxide surface.     

碳酸环己胺用于化工装备气相保护的研究

研究了气相缓蚀剂碳酸环己胺（CHC）用于化工装备保护的可能性。结果发现,CHC只要有饱和蒸气存在就可以提供良好的保护,而一旦脱离其蒸气氛围,即失去对金属的保护作用,并认为CHC属物理吸附型缓蚀剂。试验结果证明,CHC只能用于密闭体系,得出与目前普遍认为CHC可用于经常打开的包装体系相反的结论。     

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文章根据分形理论推导出了多孔介质中孔隙分布的两参数分形几何公式,建立了利用压汞资料计算孔隙分形维数来分析孔壁的粗糙度和孔径分布的不均匀程度的研究方法。将该方法应用于四川砂岩和碳酸盐岩气藏低渗透人计层改造措施研究,结果发现,无论是盐酸酸化碳酸盐碉还是土酸酸化砂岩、入口处的毛管半径均明显增另,但分形维数的变化不同,碳酸盐岩酸化后分形维数均有不同程度的增加,砂碉酸化后明显变化或有所减小,因此,碳酸盐岩酸     

伊朗卡山地区库姆组储层特征及控制因素分析

渐新统-中新统库姆组海相碳酸盐岩是伊朗卡山地区目前最有利的一套储层,且已获得了高产工业油气流。通过钻井、测井、地质、地球物理等方法,对这套储层进行了系统的研究和评价,结果发现,库姆组储层以台地相生物灰岩为主,有效储集空间为溶孔和裂缝,孔隙类型是裂缝＋孔隙型,具有双重介质特征。利用地震属性分析、波阻抗反演等方法,对库姆组有利储层的分布进行了平面上的预测,发现有利储层主要分布在断裂、构造发育部位和褶皱的转折端,但平面上和垂向上都具有强非均质性,认为沉积环境、成岩作用和构造活动是控制该区储层发育的3个主要因素。