25-降藿烷系列化合物及其在油藏地球化学研究中的应用

通过阐述烃源岩及原油中25-降藿烷系列化合物的结构、鉴定方法、成因（生物降解作用、原生作用）、降解机理,系统介绍了目前国内外25-降藿烷系列化合物的研究现状。认为25-降藿烷系列化合物在油源对比和油气成藏方面的应用和研究,有助于推动油藏地球化学的发展,同时也存在一些局限性。     

Interaction of calcium dioleate collector colloids with calcite and fluorite surfaces as revealed by AFM force measurements and molecular dynamics simulation

Spherical calcium dioleate particles (∼ 10 μm in diameter) were used as AFM (atomic force microscope) probes to measure interaction forces of the collector colloid with calcite and fluorite surfaces. The attractive AFM force between the calcium dioleate sphere and the fluorite surface is strong and has a longer range than the DLVO (Derjaguin–Landau–Verwey–Overbeek) prediction. The repulsive AFM force between the calcium dioleate sphere and the fluorite surface does not agree with the DLVO prediction. Consideration of non-DLVO forces, including the attractive hydrophobic force, was necessary to explain the experimental results. The non-DLVO interactions considered were justified by the different interfacial water structures at fluorite– and calcite–water interfaces as revealed by the numerical computation experiments using molecular dynamics simulation. The density of interfacial water at the fluorite surface is low and the fluorite surface is not strongly wetted by water molecules. In contrast to the water at the fluorite surface, water molecules at the calcite surface form tightly packed monolayer structures and the calcite surface is extensively hydrated by water molecules. The interfacial water structure agrees with the AFM force measurements and the flotation recovery data. The strong attraction between the calcium dioleate colloid and the fluorite surface, and the moderately wetted fluorite surface by water molecules explain the better flotation response of fluorite with the oleate collector colloid.     

含铁矿物的表面催化氧化作用及其环境意义

了解含铁矿物在环境地球化学和生物地球化学中所起的作用，重点在于介了解含铁矿物表面催化氧化作用对重金属As(Ⅴ)，Cr(Ⅵ)，U(Ⅵ)离子的表面还原反应，以及对有机污染物卤代烷烃、苯、氯苯、硝基苯类等芳香化合物的降解及退氯化作用，进而了解表面催化氧化作用的机制。     

烃源岩生成有机酸过程的高分辨质谱研究

研究石油中有机酸的生成过程对研究储层改造、石油润湿性及页岩油可动性评价具有重要意义。在热压生烃模拟实验基础上,对Ⅲ型烃源岩不同演化阶段生成油中的非烃馏分进行了负离子电喷雾傅立叶变换离子回旋共振质谱分析,研究了烃源岩生成有机酸过程。对样品生成有机酸分析表明,在整个演化过程烃源岩都能生成有机酸,在低演化阶段主要生成脂肪酸,随演化程度的升高,脂肪酸丰度快速减少,芳环酸开始大量生成。随演化程度的增加,芳环上短链取代基发生断裂,并促进了有机酸的缩合,使得生成的有机酸缩合度逐渐提高,高碳数有机酸逐渐减少;烃源岩生成脂肪酸系列中存在偶奇优势,生成的C16、C18脂肪酸存在异常高丰度, C16、C18脂肪酸异常丰度现象可能是污染造成的,是否与烃源岩类型及成熟度有关尚需进一步研究。     

沉积物中NSO杂环芳烃的分布特征及其地球化学意义

对金湖凹陷原油和烃源岩中分子骨架结构相似，分别含N，S，O的三类杂环芳烃－吡咯类，硫芴和氧芴系列的分布特征及其应用进行了初步探讨,烃源岩中这三类杂原子化合物的丰度一般高于原油，其在油，岩中的丰度差异按含N，O和S化合物的顺序依次降低，指示三类化合物吸附性依次降低，原油和烃源岩中三类杂原子化合物丰度具有较好的正相关性，并与芴系列具有良好的多项式关系，暗示三类杂原子化合物在原生和（或）后生作用与干酪根降解方式上可能有某些相似性与相关性，在未熟一低熟阶段，随着成熟度的增加，三类化合物的丰度逐渐增加，指示成熟度对其有一定的控制作用，NSO化合物在油气运移，成熟度评价和指相等方面具有重要意义。     

苦草(Vallisneria spiralis)释放的酚酸类物质对铜绿微囊藻(Microcystis aeruginosa)的化感作用

采用广谱性固相萃取小柱富集以10 g( FW)/L的密度培养三天后的苦草(Vallisneria spiralis)种植水,不同溶剂洗脱得到的各组分对铜绿微囊藻(Microcystis aeruginosa)的生长表现出不同程度的抑制,其中甲醇洗脱组分抑藻活性最强.去除该组分中的酚酸后,其抑藻活性下降了22.8％,表明...     

Field investigations and laboratory simulation of clogging in Lixi tailings dam of Jinduicheng,China

Clogging is one of the most important factors affecting the stability of the tailings dams. Firstly, this work investigates the clogging materials of Lixi tailings dam using ICP-AES, X-ray powder diffraction (XRD) and SEM analysis methods. The ICP-AES results indicate that Fe is the dominant element in the clogging materials. The iron contents of clogging samples collected from 2# radial-well pipe and the access hole of the starter dam are 54.35 and 40.24%, respectively. XRD spectra show that ferric hydroxide is the main initial component of the clogging materials. Other compounds such as akaganeite, hematite and goethite are products from ferric hydroxide transformation. Therefore, the clogging materials are a mixture of ferric hydroxide and its converted products. The clogging materials commonly exist in an amorphous form with a cluster microstructure when viewed under SEM. Secondly, this work uses a continuous flow column to simulate clogging in the laboratory, and the clogging materials are analyzed with XRD and SEM. The chemical analysis indicates that the iron content of the clogging materials from the experiment is 45.43%. XRD spectra show that hematite is the only compound detected. The clogging materials generated experimentally are also in amorphous cluster microstructure when viewed under SEM.     

Chemical mass balance of calcrete genesis on the Toledo granite (Spain)

The chemical mass balance of calcrete genesis is studied on a typical sequence developed in granite, in the Toledo mountains, Central Spain.

Field evidence and petrographic observations indicate that the texture and the bulk volume of the parent rock are strictly preserved all along the studied calcrete profile.

Microscopic observations indicate that the calcitization process starts within the saprolite, superimposed on the usual mechanisms of granite weathering: the fresh rock is first weathered to secondary clays, mainly smectites, which are then pseudomorphically replaced by calcite. Based on this evidence, chemical mass transfers are calculated, assuming iso-volume transformation from the parent rock to the calcrete.

The mass balance results show the increasing loss of matter due to weathering of the primary phases, from the saprolite towards the calcrete layers higher in the sequence. Zr, Ti or Th, which are classically considered as immobile during weathering, are also depleted along the profile, especially in the calcrete layer. This results from the prevailing highly alkaline conditions, which could account for the simultaneous precipitation of CaCO₃ and silicate dissolution.

The calculated budget suggests that the elements exported from the weathering profile are provided dominantly by the weathering of plagioclase and biotite. We calculate that 8–42% of the original Ca remains in granitic relics, while only 15% of the authigenic Ca released by weathering is reincorporated in the calcite. This suggests that 373 kg/m² of calcium (i.e., three times the original amount) is imported into the calcrete from allochtonous sources, probably due to aeolian transport from distant limestone formations.     

Structural characterisation of the high-pressure phase CaAl4Si2O11

Single crystals of CaAl₄Si₂O₁₁ were synthesised at 1,500?°C and 14 GPa in a multi-anvil press, and the structure of the phase determined by single-crystal X-ray diffraction at room conditions. The structure-type is that of the “hexagonal barium ferrites”. The space group of the average structure is P6 ₃ /mmc and the cell parameters are a?=?5.4223(4) Å, c?=?12.7041(6) Å, V?=?323.28(5) ų, with Z?=?2, and its density is 3.905?g?cm^?3, which is reasonable for a high-pressure alumino-silicate phase. The 22 oxygen and two calcium atoms within the unit-cell form an approximate hexagonal-close-packed array. Ten of the twelve octahedral interstices within this array that have only oxygen atoms for apices are filled with Si and/or Al. M1 octahedra share edges to form a spinel-like sheet of octahedra. The average bond length ?=?1.833 Å suggests mixed occupancy by Si and Al. The M1 octahedral sheets are linked by shared corners to pairs of face-sharing M2 octahedra containing Al, with ?= 1.918 Å. The remaining two cations of the unit-cell contents statistically occupy four tetrahedrally-coordinated interstices, which occur as face-sharing pairs. The average bond length for these sites (1.742 Å) suggests that they are occupied by Al, although Si occupancy cannot be excluded by the data. It is proposed that only one interstice of each pair is locally occupied, with the possibility of some short-range ordering of such occupancies. Complete long-range order leading to the acentric space group P6 ₃ mc is excluded by the data, as is the possibility of the average structure being comprised of merohedral (0?0?0?1) twins of P6 ₃ mc symmetry.     

胶束电动毛细管色谱法测定岩屑样品中的苯系化合物

用胶束电动毛细管色谱法测定了同一井位、不同深度岩屑样品中的苯、甲苯、乙苯和二甲苯化合物。采用 50 μm× 57cm毛细管柱 ,以 50mmol/L十二烷基硫酸钠 - 2 0mmol/L四硼酸钠溶液 (pH 9 1 6)作为缓冲溶液 ,电压 2 5kV ,检测波长 2 0 0nm ,1 6min内 ,苯、甲苯、乙苯和二甲苯可获得良好的分离。用峰面积定量 ,线性范围为 2～ 1 0 0mg/L ,最小检测浓度分别为 :0 75mg/L苯 ;0 45mg/L甲苯 ;0 39mg/L乙苯 ;0 1mg/L邻 二甲苯 ;0 31mg/L对 二甲苯。加标回收率分别为 :苯 1 0 1 % ,甲苯 99% ,邻二甲苯 97% ,乙苯 95% ,对二甲苯 1 0 0 %。方法用于实际岩屑样品的测量 ,获得各含量范围在 0 .0x～ 0 .xμg/ g ;3次平行测定的RSD在 3 3%～ 34%。