Analytical detection methodologies for methane and related hydrocarbons

The determination of methane is of strong interest to the analytical community due to its natural abundance, its potential to cause explosions and its known greenhouse effect. The current report gives a brief overview into the environmental significance of methane and an account of the existing detection protocols for methane in air and environmental samples.     

Surface characterisation of selected sorbent materials for common hydrocarbon fuels

The need to find the most efficient material for the clean-up of oil/fuel spills both at sea and on land is of extreme importance. Generally, this requires material selection based upon the adsorption properties of selected sorbent materials such as sand, swelling clays, organo-clays and cotton fibres. These adsorption properties are a function of the surface characterisation where hydrophobic and oleophilic properties are essential. From BET analysis, the adsorption isotherm of the selected materials was Types II and IV in the IUPAC classification scheme. The main adsorption mechanism for these sorbents occurred on the external surface of the material in the pores or capillaries. ESEM studies indicate that cotton capillaries contribute significantly to the adsorption process of oil. In addition, the presence of surface wax on cotton-cellulose fibre facilitated the uptake by: (a) providing a relatively hydrophobic surface for sorption of organics; and (b) providing a low surface energy environment for the capillaries to aid in oil transport. Cotton fibre was observed to have several key properties such as hydrophobicity, good affinity for hydrocarbons, rapid adsorption on contact, and high adsorption and retention through interfibre capillaries. This research provides the basis for selection of cotton-cellulose fibres compared to common and other novel alternatives such as sand and organo-clays, respectively.     

用层间地震速度差异预测地层的岩性及含油气性

地震波在地层中的传播速度与地层的岩性、孔隙含量及所含流体性质等因素有关，利用地层浅反射界面均方根速度及假设的地震层速度推算了地层深反射界面均方根速度，将其与地层深反射界面均方根速度的实测值相比较，根据两者间的差异性质和大小预测地层的岩性和含油性。把该项技术用于研究辽东湾碎屑岩地层及鄂尔多斯盆地碳酸盐岩地层的岩性及含油气性，已经取得了较好的效果．     

不同类型干酪根热解生烃动力学研究(一)

采用岩石评价仪对不同类型未成熟干酪根的热解生烃动力学特征进行了研究,分析了所得出的热解反应生烃率-温度和反应速率-温度曲线及其特征值。研究结果表明,不同类型干酪根具有不同的热解生烃动力学特征,三种类型干酪根的主要生烃阶段的温度范围(△T)不同,其规律是Ⅲ类干酪根的温度范围大于Ⅱ类干酪根,Ⅱ类干酪根又大于Ⅰ类。同一试样在不同升温速率的实验中,其最大反应速率点对应于相同的生烃率。     

柴达木盆地西南区油气充注与青藏高原隆升耦合关系的包裹体证据

准确厘定柴达木盆地内含油气储层中烃类充注历史对于全面认识青藏高原隆升构造活动影响盆地内油气的成藏和分布均具有重要意义。本文详尽地调查了柴西南地区新生界主力含油层位的流体包裹体显微测温数据及所对应的烃类充注期次及时间,全面厘清了油气充注期次与高原隆升强活动期之间的耦合关系。研究结果表明,研究区油气藏普遍存在至少2期次的油气充注,通常发生在青藏高原隆升强活动期C、D和E期(中新世以后),几乎所有的油气藏均在强活动E期发生过规模化的油气聚集,说明青藏高原隆升运动末期的构造活动是研究区油气成藏和分布的关键影响因素。由于“多期成藏、晚期富集”的油气成藏特征,早期充注的石油可能改变砂岩储层的天然亲水性,有利于晚期油气的运移和聚集,在一定程度上弥补储层在继续埋藏过程中的物性损失,预示着深层存在油气勘探潜力的可能性。     

缅甸D区块Patolon构造带烃源岩评价

从缅甸D区块Patolon-1井有机碳、饱和烃色谱特征分析等多种化验分析方法出发,主要对Patolon-1井塔本组上部煤系烃源岩和下部暗色泥岩进行系统评价。研究认为,塔本组煤系泥岩处于未熟—低成熟阶段;塔本组暗色泥岩和煤岩处于低成熟阶段。但上部煤系地层在低熟阶段可以大量生成天然气与凝析油,为该构造带的主力烃源岩,此次烃源岩的认识对D区块Patolon背斜带下一步的勘探提供重要的依据。     

Supercritical thermal decompositions of normal- and iso-dodecane in tubular reactor

Thermal decompositions of a serials of normal- and iso-dodecane mixtures with different iso/normal ratios were performed in a tubular reactor under supercritical conditions (550-680 °C, 4.0 MPa). It was found that iso-dodecane has an accelerating effect on the pyrolysis of n-dodecane depending upon iso/normal ratio of the mixture, and that accelerating factor reaches up to almost 4 at iso/normal ratio of 3/1. Decomposition conversions of the mixtures show a strong dependence on the iso/normal ratio and the temperature owing to their possible effect on the radical generation mechanism and the decomposition kinetics. In addition, iso/normal ratio of the mixture also affects the formation rates and morphologies of cokes due to the variation of decomposition conversion.     

沁水盆地中东部热演化史模拟及油气成藏响应

为还原沁水盆地中东部热演化史,以某页岩气井山西组及太原组26件海陆过渡相泥页岩实测数据为基础,利用Petro Mod软件进行了热演化史模拟,依据模拟结果对油气生成及成藏进行了分析,结果表明:研究区内烃源岩干酪根类型以Ⅲ型为主,有机质演化成熟度高,具有良好的生烃潜力;热演化史与构造演化史存在耦合作用,受印支运动及燕山运动影响,地层温度经历了缓慢上升-缓慢冷却-异常高温-快速冷却四个阶段;太原组及山西组烃源岩有机质演化过程中镜质组反射率(Ro)值发生一次跃变,最终演化至2. 0%左右,于早白垩世烃源岩发生二次生烃作用进入产气阶段,加之上覆致密的盖层形成了良好的煤系气藏。     

胶束增敏导数-恒能量同步荧光法同时测定多环芳烃混合物

本文建立了多环芳烃的胶束增敏导数 -恒能量同步荧光同时分析方法。恒能量同步扫描所得到多环芳烃的谱带位置均对应常规光谱中的最佳激发 -发射位置 ,经二阶求导后 ,消除谱带的干扰 ,所得的二阶导数 -恒能量同步荧光光谱即可用于同时测定艹屈 、荧蒽、菲等三种多环芳烃。该法快速、灵敏 ,为预测和治理水污染提供一种快速简便的测试手段。     

Catalytic reduction of NO in the presence of benzene on a Pt(3 3 2) surface

The catalytic reduction of NO in the presence of benzene on the surface of Pt(3 3 2) has been studied using Fourier transform infra red reflection-absorption spectroscopy (FTIR-RAS) and thermal desorption spectroscopy (TDS). IR spectra show that while the presence of benzene molecules at low coverage (e.g., following an exposure of just 0.25 L) promotes NO-Pt interaction, the adsorption of NO on Pt(3 3 2) at higher benzene coverages is suppressed. It is also shown that there are no strong interactions between the adsorbed NO molecules and the benzene itself or benzene-derived hydrocarbons, which can lead to the formation of intermediate species that are essential for N₂ production.TDS results show that the adsorbed benzene molecules undergo dehydrogenation accompanied by hydrogen desorption starting at 300 K and achieving a maximum at 394 K. Subsequent dehydrogenation of the benzene-derived hydrocarbons then begins with hydrogen desorption starting at 500 K. N₂ desorption from NO adlayers on clean Pt(3 3 2) surface becomes significant at temperatures higher than 400 K, giving rise to a peak at 465 K. This peak corresponds to N₂ desorption from NO dissociation on step sites. The presence of benzene promotes N₂ desorption, depending on the benzene coverage. When the benzene exposure is 0.25 L, the N₂ desorption peak at 459 K is dramatically increased. Increasing benzene coverage also results in the intensification of N₂ desorption at ∼410 K. At benzene exposures of 2.4 L, N₂ desorption develops as a broad peak with a maximum at ∼439 K.It is concluded that the catalytic reduction of NO by platinum in the presence of benzene proceeds by NO decomposition and subsequent oxygen removal at temperatures lower than 500 K, and NO dissociation is a rate-limiting step. The contribution of benzene to N₂ desorption is mainly attributed to providing a source of H, which quickly reacts with NO-derived atomic O, leaving the surface with more vacant sites for further NO dissociation.