Geochemical Characteristics of Crude Oils from Zao-V Oil Measures in Shenjiapu Oilfield

The geochemical characteristics of crude oils from Zao\|Ⅴ oil measures in the Shenjiapu oilfield are systematically described in terms of the fractional composition of crude oils, GC characteristics of saturated hydrocarbon fraction of crude oils and the characteristics of their biomarkers. The depositional environment, type and evolution of the biological source are also discussed. All pieces of evidence such as low saturated hydrocarbon fraction, high resin and asphalt, high isoprenoid alkane, weak odd\|carbon number predominance (CPI ranging from \{1.23\} to \{1.29\}, OEP ranging from \{1.14\} to \{1.16\}) and low sterane and terpane maturity parameters show these crude oils are immature oils. Low Pr/Ph ratios (\{0.66\}-\{0.88\}) and high gammacerance/C\-\{31\} hopane ratios (\{0.59\}-\{0.86\}) indicate the source rocks were formed in a slightly saline to brackish reducing lake depositional environment. Gas chromatographic characteristics of the saturated hydrocarbon fraction and the predominance of C\-\{30\} hopane in terpane series and C\-\{29\} sterane in sterane series indicate the biological source of the crude oils is composed mainly of bacterial and algal organic matter, and some algae are perhaps the main contributor of organic matter to the source rocks.

Geochemical characteristics and genetic types of crude oils from the Tertiary system in the southern part of western Qaidam Basin,Northwest China

Crude oil samples taken from the southern part of western Qaidam Basin were analyzed with GC/MS in order to understand the geochemical characteristics of crude oils.The results reveal that most crude oils are characterized by high abundance of gammacerane and C35 homohopane,which are the representative characteristics of saline lacustrine crude oils.Based on the variation of the ratios of gammacerane/C30 hopane(G/H) and C35 homoho-pane/C34 homohopane(C35/C34H),two crude oil groups,A and B,are identified.Group-A crude oils mainly occurr in the north of the study area,with higher ratios of G/H(>0.8) and C35/C34H(>1.2),whereas group-B crude oils,selected from the south of the study area,show lower ratios of G/H(<0.8) and C35/C34H(<1.0).In addition,group-A crude oils are distinguished into three subgroups in accordance with their different ratios of G/H and C35/C34H and different distribution characteristics of n-alkanes,isoprenoids and steranes.These may be helpful for understanding the distribution characteristics of crude oils in the southern part of western Qaidam Basin and providing clues to the forthcoming exploration of crude oils and gas.

Compositional characteristics and geochemical significance of light hydrocarbons for crude oils in Tarim Basin, China

Light hydrocarbons, especially C-7 isoalkanes, cyclopentanes, cyclohexanes and n-heptane in 540 oils from the Tarim Basin were studied systematically. The results suggested the K-1 values [(2-MH+2,3-DMP)/(3-MH+2,4-DMP)] of crude oils vary from a lowest value of {0.78}, to a highest value of {1.54}, but the K-1 values of the majority of oil samples (80%) range from {0.90} to {1.20}. However, the absolute contents of (2-methylhexane+ 2,3-dimethylpentane) and (3-methylhexane+2,4-dimethylpentane) in the total light hydrocarbons (C-4-C-7) show a similar variation trend. The variation of K-1 values of crude oils can suggest a typical sedimentary environment for source rocks. Therefore, according to the compositional characteristics of C-7 light hydrocarbons in light of the steady-state catalytic hypothesis, non-marine oils from the Yingmaili area and marine oils from the Tazhong uplift in the Tarim Basin were genetically classified.

Geochemical characteristics of aromatic hydrocarbons in saline lacustrine crude oils and their significance as exemplified by the south area of western Qaidam Basin

Based on quantitative GC-MS analysis of 40 crude oil samples collected from the south area of western Qaidam Basin,one of the largest saline lacustrine basins in China,the geochemical characteristics of aromatic hydrocarbons in oils were studied systematically in this paper.Among those constitutes,naphthalene(43% 59%),phenanthrene(12% 21%) and taromatic-sterane series(6% 28%) were the main ones of aromatic hydrocarbons.The ratio of aromatic hydrocarbon maturity parameter vs.saturated hydrocarbon maturity parameter C 29 20S/(20S+20R) shows that some aromatic hydrocarbon maturity parameters are not suitable for low-mature oils,including MPI,MNR,DNR,etc.Meanwhile,maturity parameters for dibenzothiophene and taromatic-sterane series are more appropriate for low maturity saline lacustrine crude oils.Based on the ratio of 4,6-DMDBT/1,4-DMDBT,the R c values are within the range of 0.59% 0.72%.However,the abundance of dibenzothiophene(DBT) is low,and the dibenzofuran(DBF) content is even lower,suggesting that the crude oils were formed in a saline lacustrine anaerobic environment.The high abundance of C 26 triaromatic steroid also indicates that the source material is brackish water-saline water with strong reducibility.

A Study on the Pyrolytic Characteristics of Xanthoceras Sorbifolia Husk and Its Crude Cellulose Extract

Huge amounts of Xanthoceras sorbifolia husks(XSH)are typically discarded after oil extraction.Since pyrolysis represents a promising solution to harness the bio-energy of XSH,in the present work the pyrolytic and kinetic characteristics of XSH and related crude cellulose extract(CCE)were studied considering different rates of heating(10,30 and 50℃ min^(-1)).The pyrolysis activation energy,pre-exponential factors and mechanism function were computed using different models namely Popescu,FWO(Flynn-Wall-Ozawa)and KAS(Kissinger-Akahira-Sunose).The pyrolysis process was articulated into three stages:dehydration(Stage I),primary devolatilization(Stage II),residual decomposition(Stage III).Marked variations in the average activation energy,thermal stability,final residuals and rate of reaction were noted.Stage II of XSH and CCE could be described by the Avramic-Erofeev equations.The average activation energies of XSH and CCE were found to be 269 and 296 kJ mol^(-1),respectively.

Experimental research on characteristic of start-up pressure wave propagation in gelled crude oil by large-scale flow loop

In order to research start-up pressure wave propagation mechanism and determine pressure wave speed in gelled crude oil pipelines accurately,experiment of Large-scale flow loop was carried out.In the experiment,start-up pressure wave speeds under various operation conditions were measured,and effects of correlative factors on pressure wave were analyzed.The experimental and theoretical analysis shows that thermal shrinkage and structural properties of gelled crude oils are key factors influencing on start-up pressure wave propagation.The quantitative analysis for these effects can be done by using volume expansion coefficient and structural property parameter of gelled crude oil.A new calculation model of pressure wave speed was developed on the basis of Large-scale flow loop experiment and theoretical analysis.

Characteristic Temperatures of Waxy Crude Oils

Gel point or pour point is widely used to evaluate the low temperature flowability of crude oil. However, it is not adequate to describe the gelling properties of waxy crude oils under flow conditions with gel point or pour point, since the rheological behavior of crude oils is dependent on shear history. Waxy crude oils tend to gel at a low temperature. Based on gelation theory, the characteristic temperature of waxy crude oil was determined by analyzing viscosity-temperature data. Two mathematical models were developed for calculating characteristic temperatures of virgin crude oils and pour point depressants (PPD) beneficiated crude oils, respectively. By using these two models, the characteristic temperatures of crude oils that have experienced shearing and thermal histories can be predicted. The model for predicting the characteristic temperature of virgin crude oils has an average relative deviation of 4.5%, and all predicted values have a deviation within 2 ℃. Tested by 42 sets of data, the prediction model for crude oil treated with PPD has a high accuracy, with an average relative deviation of 4.2%, and 95.2 percent of predicted values have a deviation within 2 ℃. These two models provide useful ways for predicting the flowability of crude oils in pipelines when only wax content, wax appearance point and gel point are available.

Experimental study of C-band microwave scattering characteristics during the emulsification process of oil spills

In this study,oil spill experiments were performed in a water tank to determine changes in the surface scattering characteristics during the emulsification of oil spills.A C-band fully-polarimetric microwave scatterometer and a vector network analyzer were used to observe films of the following oils:crude oil with an asphalt content below3%that is prone to emulsification(type A),fresh crude oil extracted from an oilfield(type B),and industrial crude oil that was dehydrated and purified(type C).The difference in the backscatter results between the emulsified oil film and the calm water surface under C-band microwaves and the influence of the emulsification of the oil film on the backscatter were analyzed in detail.The results demonstrate that under a low-wind and no-waves condition(the maximum wave height was below than 3 mm),the emulsification of crude oil could modulated the backscatter through changes in the surface roughness and the dielectric constant,where the surface roughness had the dominant effect.The surface backscatters of the type B oil were greater than that of the type C oil in both the emulsified and non-emulsified states.In the non-emulsified state,the average differences in the backscatter between the type B and C oils were 2.19 dB,2.63 dB,and 2.21 dB for the polarization modes of VV,HH,and HV/VH,respectively.Smaller corresponding average differences of 0.98 dB,1.49 dB,and 1.5 dB were found for the emulsified state with a 20%moisture constant for the oil film.The results demonstrated that the surface roughness of the different oil films could vary due to the differences in the oil compositions and the oil film properties,which in turn affect the backscatter of the oil film surface.

塔河油田盐下地区原油地球化学特征及不同期次油气成藏贡献

对于多旋回叠合盆地,油气藏形成的过程往往伴随着多期次的原油充注,但并非每一期原油充注都对现今油藏形成起到关键作用。流体包裹体方法只能对原油充注期次和时间进行限定,而无法确定各期充注原油对油藏的贡献。针对上述问题,以塔河油田盐下地区奥陶系碳酸盐岩油藏为例,采用原油地球化学、流体包裹体法、荧光光谱和单井模拟分析方法,系统揭示了研究区原油的荧光特征、油气成藏期次和成藏时间。原油生物标志化合物参数分析结果表明,其母质相同且沉积于海相弱还原环境,再通过与研究区烃源岩进行油源对比,确定了原油均来自下寒武统玉尔吐斯组烃源岩。原油芳烃中甲基菲指数和二苯并噻吩参数是定量评价原油成熟度的有效指标,计算得到塔河油田盐下地区原油成熟度(R_(o))在0.90%~1.47%之间,可能对应了多期油气充注。此外,在对盐下地区奥陶系储层油包裹体荧光光谱分析、共生盐水包裹体测温和测盐的基础上,结合单井埋藏史和热史模拟,确定盐下地区存在加里东中期(420 Ma)、海西中期(318 Ma)和喜马拉雅晚期(10 Ma)3期原油充注。对比原油和3期油包裹体荧光光谱参数,认为喜马拉雅晚期是盐下地区的主成藏期,为盐下地区的奥陶系油藏贡献了最多的原油。

渤海湾盆地南堡凹陷2号构造带油气地球化学特征与来源

渤海湾盆地南堡凹陷2号构造带具有多洼、多层系供烃的特征。为了揭示其复杂的油气来源,开展色谱-质谱等地化测试,分析原油地化特征,将原油分为3类,并确定每类原油的来源。结果表明:(1)Ⅰ类原油主要分布于西构造带沙三段储层中,原油中C27与C29规则甾烷相对含量接近,孕甾烷参数((孕甾烷+升孕甾烷)/规则甾烷)和甾烷异构化参数(C29甾烷20S/(20R+20S)、C29甾烷ββ/(αα+ββ))较高,具有水生生物和高等植物共同输入特征,原油成熟度高,来源于沙三段烃源岩;(2)Ⅱ类原油主要分布于西构造带东二段储层中,原油中C29规则甾烷含量具明显优势,孕甾烷参数和甾烷异构化参数均低,原油母质中高等植物具有明显优势,原油成熟度整体偏低,来源于沙一段—东三段烃源岩;(3)Ⅲ类原油主要分布于东构造带东三段和西构造带东一段和明化镇组储层中,原油中C29规则甾烷具有一定优势,孕甾烷参数较低,甾烷异构化参数较高,以高等植物输入为主,原油成熟度较高,为3套烃源岩的混合来源;(4)原油4-/1-MDBT和Ts/Tm指数具有沿断层向浅部层系减小的趋势,且原油甲基菲换算的镜质体反射率与下覆烃源岩镜质体反射率一致,表明研究区原油具有原地供烃的特点。本研究成果为研究区的浅层精细勘探及深层勘探提供理论指导。

乍得Bongor盆地北部斜坡带原油地球化学特征与成因

【目的】中非裂谷系乍得Bongor盆地北部斜坡带原油的物性与地球化学特征均存在明显差异。探讨其差异性特征及主控因素,并可为Bongor盆地及周边地区石油勘探工作中原油性质的预测提供部分思路与依据。【方法】利用原油族组分分离、气相色谱及色谱—质谱等方法,对北部斜坡带41件原油样品的物性及分子标志化合物组成进行了系统分析。【结果与结论】不同级别的生物降解作用是导致Bongor盆地原油物性与地球化学性质差异的主要原因。根据正构烷烃、无环类异戊二烯烃的相对丰度与分布特征及色谱基线特征,将原油划分为未降解原油、轻微降解原油与严重降解原油。埋深是影响原油降解强度的首要因素,当埋深小于800 m时,绝大部分原油遭受了严重的生物降解;当埋深大于1300 m时,原油基本未遭受降解;当埋深介于800~1300 m时,降解程度受距深大断裂的距离、上覆盖层的厚度与圈闭类型共同控制。

嗜盐原油降解混合菌处理采出水特性研究

针对高矿化度高硫化物的油田采出水的生物处理,从含油污泥、采出水等样品中经初筛、复筛获得嗜盐原油降解菌14株,选取降解率最高的4株进行复配,构建出嗜盐原油降解混合菌TG-1。16 SrDNA序列分析表明4株菌分别为不动杆菌(Acinetobacter);副蕈状芽胞杆菌(Bacillus paramycoides);芽孢杆菌(Bacillus sp.);肠杆菌(Enterobacter sp.)。考察了TG-1处理采出水性能,发现最适矿化度范围在30 g/L以下,最高耐受硫化物质量浓度可达150 mg/L,原油质量浓度不高于500 mg/L去除效果最好。将TG-1应用于生物接触氧化装置中,在pH值7~8、温度30℃左右、溶解氧4~5 mg/L、水力停留时间为4~12 h以及进水原油质量浓度为10~100 mg/L的条件下,出水原油质量浓度小于15 mg/L,满足克拉玛依油田注水水质标准A2。

准噶尔盆地沙湾凹陷原油地球化学特征与油源分析

沙湾凹陷作为准噶尔盆地西北缘重要的油气富集凹陷,在红车断裂带和斜坡区域均有重大油气发现。为明确沙湾凹陷周缘构造原油的来源,采用全烃地球化学分析方法,分析准噶尔盆地西北缘地区4套烃源岩和原油的地球化学特征,进行油-源和油-油对比研究。研究认为沙湾凹陷原油可分为5类,5类原油生物标志化合物指标与碳同位素分别表现为不同的特征,其中:A_(1)亚类原油来源于二叠系下乌尔禾组烃源岩高成熟阶段,A_(2)亚类原油来源于下乌尔禾组烃源岩成熟阶段,B类原油来源于风城组和下乌尔禾组的烃源岩的混合,C类原油来源于二叠系风城组烃源岩成熟—高成熟阶段,D类原油为侏罗系烃源岩产物。

Low-temperature oxidation of light crude oil in oxygen-reduced air flooding

Light crude oil from the lower member of the Paleogene Xiaganchaigou Formation of Gaskule in Qinghai Oilfield was selected to carry out thermal kinetic analysis experiments and calculate the activation energy during the oil oxidation process.The oxidation process of crude oi l in porous medium was modeled by crude oil static oxidation experiment,and the component changes of crude oil before and after low-temperature oxidation were compared through Fourier transform ion cy-clotron resonance mass spectrometry and gas chromatography;the dynamic displacement experiment of oxygen-reduced air was combined with NMR technology to analyze the oil recovery degree of oxygen-reduced air flooding.The whole process of crude oil oxidation can be divided into four stages:light hydrocarbon volatilization,low-temperature oxidation,fuel deposition,and high temperature oxidation;the high temperature oxidation stage needs the highest activation energy,followed by the fuel deposition stage,and the low-temperature oxidation stage needs the lowest activation energy;the concentration of oxygen in the reaction is negatively correlated with the activation energy required for the reaction;the higher the oxygen concentration,the lower the average activation energy required for oxidation reaction is;the low-temperature oxidation reaction between crude oil and air generates a large amount of heat and CO,CO_(2) and CH4,forming flue gas drive in the reservoir,which has certain effects of mixing phases,reducing viscosity,lowering interfacial tension and promoting expansion of crude oil,and thus helps enhance the oil recovery rate.Under suitable reservoir temperature condition,the degree of recovery of oxygen-reduced air flooding is higher than that of nitrogen flooding for all scales of pore throat,and the air/oxygen-reduced air flooding de-velopment should be preferred.

准噶尔盆地盆1井西凹陷侏罗系原油成因与来源

准噶尔盆地多套烃源岩、多期生排烃过程导致了原油来源的复杂性。利用原油物性、气相色谱-质谱等资料,综合厘定盆1井西凹陷原油的地化特征与来源。结果显示,研究区存在3种类型原油:Ⅰ类原油具有高含量25-降藿烷、高含量伽马蜡烷和大斜率“上升型”三环萜烷分布特征,是强还原沉积环境有机质形成的主生油窗阶段原油,来自于风城组烃源岩;Ⅱ、Ⅲ类原油具有较低含量伽马蜡烷和“山峰型”或弱“上升型”三环萜烷分布特征,是弱还原沉积环境有机质形成的原油,原油主要来自下乌尔禾组烃源岩,混有降解的风城组来源原油,其中,Ⅱ类原油是主生油窗阶段的原油,Ⅲ类原油是高过成熟阶段的原油。油藏具有多期充注特征,中晚侏罗世聚集的Ⅰ类原油分布广泛,但遭受了强烈生物降解,对成藏贡献小;晚白垩世聚集的Ⅱ类原油在砂体中长距离运移,多在凸起区汇聚成藏;新近纪,储层物性变差,原油难以长距离运移,该时期聚集的Ⅲ类原油多在断裂带附近成藏。

Geochemistry and genesis on saturated hydrocarbon of crude oils in Gas Hure Oilfield in Qaidam Basin

Gas Hure Oilfield is the biggest one in the Qaidam Basin.Through intensive sampling and GC-MS analysis,the authors analyzed the geochemical characteristics of the crude oils in the Gas Hure Oilfield.The results show that the crude oils have even-odd carbon predominance for n-alkanes.In shallow reservoir,part of crude oils suffered biogenic degradation.As for normal oils,they have low Pr/Ph ratios with abundant gammacerane and C35 homohopane,which indicate that the crude oils are formed in strong reducing salt water environment.Compared deep(E13) reservoir with shallow(N1-N12) reservoir,the ancient salinity of sedimentary environment of N1--N12 crude oils is slightly higher than that of E13 crude oils;the C-21/C+22 ratios of crude oils are 1.02-1.71 with a higher abundance of C27 sterane,which shows that their mainly origin matrix are bacteria and algae;the C29 sterane 20S/(20S+20R)is generally low,the ratio in deep E13 reservoir distributes between 0.31 and 0.40,but in shallow reservoir is relatively low with 0.29-0.36.At the same time,C29 sterane αββ/(αββ+ααα)and Ts/Tm both are extremely lower.All the above show that the crude oils in Gas Hure are mainly low mature oils,although the maturity of deep reservoir crude oils is slightly higher than shallow one.

非洲Melut盆地北部不同地区原油有机地球化学特征及意义

为了明确Melut盆地北部不同地区原油母质来源、沉积环境及亲缘关系,采用饱和烃色谱及色谱-质谱方法,开展了盆地北部不同地区原油地球化学特征分析及对比。研究表明,盆地北部各地区原油正构烷烃无明显奇偶优势,Ts/Tm值1.36~3.47、C_(31)升藿烷22S/(22S+22R)比值0.54~0.60、αααC_(29)20S/(20S+20R)与C_(29)αββ/(ααα+αββ)比值大于0.4,总体表现为成熟原油;伽马蜡烷指数普遍小于0.1,C_(21)三环萜烷具有明显优势,Pr/Ph值0.97~2.31,均值1.61,指示其烃源岩形成于弱还原-弱氧化的淡水湖相环境;生油母质为Ⅱ~Ⅲ型混合型。不同地区原油母质来源及成熟度有差异:Moleeta次凹东坡原油为单峰后峰态分布,高碳数正构烷烃含量占优势,C_(24)TeT/C_(23)TT平均值大于1,具有明显的陆源高等植物贡献,原油成熟度较低,发育重质—中质油;Jamous次凹深洼区原油为前峰优势的双峰态分布,C_(24)TeT/C_(23)TT值小于1,生烃母质除有陆源高等植物贡献外,水生生物也有重要贡献,原油成熟度较高,发育中质—轻质油;Palogue油田位于两个生烃次凹之间,具有混源特征;AYT(Abyat)油田原油主要来自Jamous次凹深洼区,同时有原地烃源岩的生烃贡献。Jamous次凹斜坡中部翘倾断裂带的发育,将次凹分割成两个次级断陷,为斜坡东部AYT地区烃源岩的发育提供了构造条件。翘倾断裂带使Jamous次凹斜坡中部抬升变浅,局部发育弱氧化环境下的浅水砂泥互层沉积。

黑木耳水提物和粗多糖溶液的流变特性及饮料开发

【目的】研究黑木耳水提物(Auricularia auricula water extract,AWE)和黑木耳粗多糖(Auricularia auricula crude polysaccharide,ACP)溶液的流变特性,优化饮料配方,为黑木耳饮料的开发提供科技支撑。【方法】观察不同质量浓度和均质压力下AWE和ACP溶液的流变特性;采用单因素和正交试验优化黑木耳饮料配方。【结果】0.3%~1.5%的AWE与ACP溶液都具有明显的剪切稀化特征,表现为假塑性流体,且为非牛顿流体;随着AWE与ACP质量浓度的降低,其流动行为指数增加,稠度系数降低(P<0.05),0.3%~0.6%AWE溶液和0.3%ACP溶液呈现稳定的流体特性。4~12 MPa均质处理显著提高0.6%AWE和ACP溶液的流动行为指数,同时降低稠度系数,均呈现稳定的流体特性;相同均质压力下0.6%AWE比ACP溶液的黏度更低、流动性更佳。8 MPa均质压力处理的0.6%AWE溶液的平均粒径(6.51±0.02)μm和稳定系数(0.926±0.024)达到平衡。单因素和正交试验优化黑木耳饮料配方为:AWE0.6%、冰糖6%以及柠檬酸0.1%;饮料呈浅褐色,具黑木耳特有风味,口感细腻丝滑。【结论】0.3%~1.5%AWE和ACP溶液均为假塑性流体,且为非牛顿流体;4~12 MPa均质提高了0.6%的AWE和ACP溶液流动性,8MPa均质处理0.6%AWE溶液体系的稳定性最佳,从而确定黑木耳饮料加工以0.6%AWE为生产原料,采用8 MPa作为均质压力。黑木耳饮料最佳配方为:AWE 0.6%、冰糖6%以及柠檬酸0.1%。

胶凝原油水力悬浮输送教学实验装置设计研究

我国大部分油田采用加热集输方式输送,能量消耗较大。原油不加热集输技术是油田节能领域的研究热点之一,该文提出原油水力悬浮输送的理念,即使用技术手段将胶凝原油整形为分散颗粒,在不加热的条件下借助水动力实现流态化,并以悬浮状态输送。该文根据原油生产实际,研制了胶凝原油水力悬浮输送模拟实验装置,该装置不仅能服务于多相流方向研究生实践能力的培养,同时也有助于本科流体力学开放性实验的开展,还可以进行胶凝原油整形效果和不同条件下水-胶凝原油流动特性等的实验研究,助力相关科研工作。

油滴的宏观聚并机制及油膜分子之间的微观相互作用研究

为研究油滴聚并过程中油滴之间的微观相互作用,通过有限元模拟方法,结合乳状液稳定性实验与分子动力学模拟技术,研究了油井采出液中乳化油滴的聚并行为,并分析了油滴聚并的影响因素。研究结果表明:2个油滴在聚并过程中液膜位置处流体流速较高,聚并完成后达到稳定;油滴尺寸与聚并时间并不存在明显的对应关系,当2个油滴半径不同时,较大的油滴移动位移较小;初始时刻,油膜和水相之间存在明显的界限;碳链越长,乳状液越稳定,在碳原子数量相同的条件下,原油组分对乳状液稳定性的影响由小到大为饱和烃、碳碳双键、碳碳三键、环烷烃;沥青质含量升高是造成乳状液体系乳化能力和乳化稳定性增强的主要原因。该研究对提高原油油水分离效率,降低原油储运成本有重要意义。