GEOCHEMICAL CHARACTERIZATION OF A BIODEGRADED CRUDE OIL, ASSRAN FIELD, CENTRAL GULF OF SUEZ

A crude oil sample from the Assran field in the Central Gulf of Suez (Egypt) was analysed geochemically and characterized in terms of a variety of source and maturity dependent biomarkers. Biodegradation was indicated by increasing concentration ratios of Pr/n-C₁₇ and Ph/n-C₁₈. However, biodegradation was only slight as GC-MS analyses of the saturate and aromatic fractions showed that hopanes, steranes, aromatic steroids and polycyclic aromatic compounds including sulphur heterocycles remained intact. The sterane and hopane distributions showed a predominance of C₂₇ steranes, a low diasterane index, an abundance of gammacerane, a high homohopane index and an oleanane index < 0.2. The results indicate that the Assran-10 crude oil was derived from a marine carbonate source deposited in a highly reducing saline environment with a high bacterial contribution, consistent with the Upper Cretaceous Brown Limestone or Lower Eocene Thebes Formation containing Type IIS kerogen. Maturity parameters based on changes in the stereochemistry at chirality centres in hopane and sterane nuclei, such as C₃₀βα/(βα+αβ) and C₃₁ 22S/(22S+22R) hopanes and C₂₉ββ/(ββ+αα) and C₂₉ 20S/(20S+20R) steranes, together with triaromatic sterane cracking ratios, indicate that the oil sample was marginally mature. The results also suggest that biodegradation is probably due to sulphate-reducing anaerobic bacteria.     

柴达木盆地东部地区生物气形成机制

生物气是沉积物在成岩作用早期受生物化学作用形成的最终产物之一。对生物产气模式的传统认识是,沉积有机质在厌氧环境下,经微生物降解为能被产甲烷菌利用的小分子底物,然后通过乙酸发酵和CO2还原,形成甲烷。文中突破传统认识,提出弱成岩阶段的低温热力与微生物共同作用是柴东地区生物气形成的主要机制。传统认识强调继承性活性有机质的作用,而文中分析发现,柴达木盆地东部第四系沉积物内继承性活性有机质并不丰富。研究认为,在低温热力作用下可产生一些次生活性有机质,该部分物质为一定埋藏深度的生物甲烷气提供重要营养底物来源。     

塔里木盆地塔东2井稠油有机地球化学特征

塔里木盆地中央隆起带东段的塔东2井在寒武系储集层中获取少量稠油。该稠油具有m(Pr)/m(Ph)高、伽马蜡烷含量高、24-降胆甾烷含量高、C28甾烷含量高、甲藻甾烷及三芳甲藻甾烷含量高、4-甲基-24-乙基胆甾烷及芳构化甾烷含量高的特点,地质分析与油源对比认为,原油来源于寒武系。原油中含有25-降藿烷系列,表明原油曾发生生物降解作用;芳烃馏分中存在大量菲、蒽、苯并蒽、苯并荧葸、芘等化合物及流体包裹体均一化温度表明,原油曾经历了热蚀变作用。流体包裹体均一化温度结合埋藏史分析认为,塔东2井原油是在(450-440)×106a前形成的。     

生物可降解润滑油

传统的润滑油部分流失或变质后废弃于大气和水土中,污染资源、破坏了生态环境和平衡。生物可降解润滑油性能符合润滑油的要求,废弃后能被微生物分解,不污染环境。生物降可解润滑油的基础油和添加剂都与常规润滑油的不同,植物油作基础油及无灰分添加剂是生物降解润滑油发展方向。     

加拿大油砂沥青中极性化合物的电喷雾——高分辨质谱研究

目前,生物降解作用对饱和烃生物标志物、芳香烃生物标志物参数以及小分子含氮化合物参数影响的研究较多,而对大分子极性化合物组成影响的研究较少。采用负离子电喷雾—傅立叶变换离子回旋共振质谱（ESI FT-ICR MS）分析不同降解级别的加拿大油砂沥青中酸性及非碱性氮化合物分子组成,结果表明,加拿大油砂沥青中杂原子化合物组成非常复杂,共鉴定出10种不同杂原子类型（N₁、N₁O₁、N₁O₂、N₁S₁、O₁、O₁S₁、O₂、O₂S₁、O₃、O₄）的化合物,其中以O₂类化合物为主。随着生物降解程度的加深,N₁、N₁O₁及O₁类化合物的相对丰度逐渐降低,而O₂及O₂S₁类化合物的相对丰度显现出逐渐增加的趋势;高分辨质谱分析在石油大分子杂原子化合物研究方面所独有的优势,为石油地球化学研究提供了新的思路。     

有机地球化学方法识别中等生物降解油藏油水界面

利用有机地球化学方法确定中等生物降解油藏LH11-1的油水界面深度,以取心率高的LH11-1-2井为实验对象,对35个岩心和岩屑样品进行Rock-Eval和GC/MS实验分析。岩心样品饱和烃GC/MS分析表明,其生物降解程度为3—5级,且随深度增加而逐渐加强。样品含油量、Pow值、(S1+S2)/R、重质油指数、饱和烃生物降解特征、伽马蜡烷/奥利烷等6个有机地化参数均在1 250.9 m处异常变化,揭示储层岩石烃类含量、组成、物理化学性质及生物降解级别沿油水界面方向具规律性变化,但在油水界面处异常,据此可判定1 250.9 m是LH11-1-2井新确定的油水界面深度,与测井解释相差3.8 m,可能与油水过渡带范围较大有关。利用有机地球化学方法,可较好地识别中等生物降解礁灰岩油藏的油水界面。     

海上平台采油污水石油烃类物质的脱除

分别采用离心沉降法、生物降解法和化学絮凝法,脱除海上钻井平台采油污水中质量浓度为４６３３ｍｇ／Ｌ的石油烃类物质（ＴＰＨ）。结果表明,随着生物降解时间的延长,ＴＰＨ质量浓度降低;当前者达到４８ｈ时,后者变化趋于稳定,此时ＴＰＨ脱除率为９３．７％。ＵＢＤ菌种降解的高效期为１２～４８ｈ。在离心加速度为４３０２２ｍ／ｓ２ 的条件下,随离心沉降时间的延长,ＴＰＨ质量浓度降低;离心沉降５０ｍｉｎ后,ＴＰＨ脱除率达到９５．５％。以硫酸铝为絮凝剂,采用化学絮凝法处理采油污水,１２ｈ后ＴＰＨ脱除率达到９６．７％。     

紫外辐射固化法制备可生物降解高吸水性树脂及其性能的研究

以N,N′-亚甲基双丙烯酰胺(NMBA)为交联剂,2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酰胺(AM)、壳聚糖(CTs)为单体,采用紫外辐射固化法,在无任何气氛保护和不加引发剂的条件下,合成了高吸水性CTs/AM/AMPS树脂。利用FTIR和TG等方法分析了该树脂的化学结构,并考察了合成条件对其吸水性能的影响。实验结果表明,适宜的合成条件(w:基于反应体系的质量)为:n(AM)∶n(AMPS)=5∶1、CTs用量3.00%(w)、NMBA用量0.54%(w)、体系pH=2.5、3种单体总用量8.85%(w)、固化时间9 min。在此条件下合成的CTs/AM/AMPS树脂的最大吸水倍率为1 615 g/g。CTs在受热过程中由于网格被破坏而发生降解,因此CTs/AM/AMPS树脂为环保型可生物降解树脂。     

Surface activities,biodegradability and antimicrobial properties of n-alkyl glucosides,mannosides and galactosides

n-Alkyl α-and β-glucopyranosides, α-D-mannopyranosides and β-D-galactopyranosides with alkyl chains having from 8 to 12 carbon atoms were synthesized and their surface properties-such as static surface tension (γ), critical micelle concentration (CMC), occupation area of molecule, dynamic surface tension and foaming properties, biodegradability and antimicrobial activities—were evaluated. Alkyl glycosides containing C8 to C12 carbon chains showed surface activities and critical micelle concentrations. D-Glucoside, D-mannoside and D-galactoside having the same alkyl chain showed similar surface tension lowering at CMC (γ_CMC) and occupation area of the molecule at the surface. Among the alkyl glucosides, α-anomers were less hydrophilic than β-anomers. All alkyl glycosides tested in this study were readily biodegraded by activated sludge of a municipal sewage plant compared to those of ethoxylated nonionic alcohols. The difference of the hydrophilic glycopyranoside group in biodegradability was not seen clearly. n-Alkyl glycosides containing C8 to C12 alkyl chains showed a broad spectrum of increasing antimicrobial activity. n-Dodecyl α-D-mannopyranoside was the most effective, the order of antimicrobial activity being mannopyranoside > glucopyranoside > galactopyranoside group. Members of this class of compounds exhibit the physicochemical and biological properties needed both for a wide range of applications and for environmental acceptance.