Oil:Oil Correlation for Some Oil Fields in the North Western Part of the Western Desert,Egypt

Abstract

Physical and specific geochemical analyses are used in detail for the petroleum geochemical studies to permit the correlation of six crude oil samples from Western Desert Egypt. Different analytical techniques, including liquid chromatographic separation, gas chromatography, and gas chromatography-mass spectrometry (GC-MS), were used to characterize the oil samples. The oils were identified using oil characterization parameters including specific gravity (°API), sulfur content, distribution of n-alkanes, carbon preference index (CPI), pristane/phytane ratio, isoprenoid/n-alkane ratios, and detailed biological marker analysis. All these parameters showed that the studied oil samples are correlated with each other, where they are similar in their oil type maturation and source depositional environments.     

准噶尔盆地东南缘油页岩有机地球化学特征及含气潜力

准噶尔盆地页岩气尚属于研究起步阶段,勘探程度低,还未发现页岩气藏。通过对准噶尔盆地东南缘雅玛里克山、水磨沟、三工河等地区上二叠统芦草沟组油页岩样品进行有机地球化学特征系统分析,认为：芦草沟组油页岩有机碳平均含量为9.71%,油页岩氢指数(I_H)平均值为471.56mgHC/g_TOC,有机质类型主要为Ⅱ型,处于低熟—成熟热演化阶段。通过与北美五大页岩气系统地球化学参数和地质参数对比,初步确定准噶尔盆地东南缘存在发育热成因页岩气藏的条件,部分区域可能有生物成因气生成。3个地区中,以三工河地区油页岩有机质丰度最高,有可能成为研究区页岩气勘探开发的有利区域。     

塔里木盆地顺北油田油气来源研究

基于塔里木盆地顺北地区原油和天然气样品的地球化学特征分析,研究了顺北地区奥陶系中下统油气来源。通过饱和烃色谱及饱和烃、芳烃色谱—质谱、全油及族组分碳同位素检测,发现原油样品中C23三环萜烷占优势,伽马蜡烷含量低,C27-C28-C29ααα20R规则甾烷表现为不规则的"V"字形分布,规则甾烷相对重排甾烷含量高,原油碳同位素偏轻,与柯坪露头及孔探1井等下寒武统烃源岩有很好的亲缘性;天然气δ13C1值为-50.7‰^-44.7‰,天然气δ13C2值为-36.1‰^-33.1‰,干燥系数为0.520~0.883,为原油伴生气,油气同源,判断顺北油田油气主要来源于下寒武统烃源岩。通过已钻井岩相、沉积相和全盆地地震相资料,预测下寒武统烃源岩在塔里木盆地广泛分布,厚度在30 m左右,有机碳含量高,生烃潜力大,具有长期生烃、多期供烃的特点,能提供充足的油气资源,是塔里木盆地台盆区最主要的烃源岩。     

油气化探地球化学场分析及研究

地球化学场除具有时间、空间要素,还具有环境约束条件特征,因此,其函数表达式应为Gij=Fij(X,Y,Z,T,C)。油气化探地球化学场是成烃物质油气地球化学场动态演化阶段中因油气勘探需要而在特殊时期设定的,通过油气化探地球化学场分析,研究化探指标物质量(质量、数量)在不同区域空间上的变化,进而为油气勘探服务;油气化探地球化学场因研究内容、目的、目标以及研究方法、手段、范围的不同可划分为多种不同类型地球化学场;微观和宏观、区域和局部、动态和静态相结合的理念应始终贯穿于油气化探地球化学场研究,油气化探地球化学场的客观分析和研究可为油气化探的勘探应用提供理论分析依据。     

Crude Oil Geochemistry and Its Relation to the Potential Source Beds for Some Meleiha Oil Fields in the North Western Desert, Egypt

The results of the geochemical evaluation for eleven crude oil samples from some Meleiha oil fields revealed that, these oils have high specific gravity (°API), low sulfur content and rich in saturated hydrocarbons. Two oil classes were recognized. The first is carbonate oils of high maturity level, originated from marine origin. The second, deltaic oils of moderately level of maturation, derived mainly from terrigenous sources. Oil: source correlation for the productive oils and the extracts of the potential source beds revealed a genetic close relationship between oils and extracts of Khatatba and Alam El Bueib formations. This indicates that the source of the oils in the study area may be related to mixed sources of these formations.     

塔里木盆地塔河油田AT2井区高精度化探异常及其开发地质意义

为了评价塔里木盆地塔河油田AT2井区三叠系中、上油组多个圈闭的含油气性,采用基于烃类微渗漏的高精度化探技术在该井区进行了油气地球化学精查研究。选用的地球化学勘探指标均为活动态指标,包括游离烃、物理吸附烃以及顶空气。采用测网方式采集了近地表土壤样品,网度为0.25 km×0.25 km,在重点圈闭上方采用了0.1 km×0.1 km加密采样网格。以游离烃甲烷、物理吸附烃甲烷、顶空气甲烷为代表性指标,研究了AT2井区地球化学异常特征。在此基础上,确定了5个综合地球化学异常区（对应于5个圈闭）。通过化探—地质双因素评价方法,对上述5个化探异常区进行了排序,评价了圈闭的含油气性,为油田滚动开发提供了地球化学依据。      

川中地区侏罗系天然气与原油轻烃地球化学特征对比

天然气伴生凝析油及轻质油的轻烃地球化学参数常常被用于天然气成因和油—气对比研究,但蒸发分馏等次生作用对天然气和伴生原油的轻烃组成会产生一定的影响。基于川中地区16件侏罗系天然气与伴生凝析油或轻质油样品气相色谱分析,探讨了轻烃组成及相关地球化学参数在天然气和原油中的差异。研究表明：蒸发分馏作用对油气轻烃组成影响明显,相对于伴生原油,天然气轻烃组成具有高异构烷烃和正构烷烃相对含量,而贫环烷烃和芳香烃的特征。蒸发分馏作用对甲基环己烷指数、环己烷指数、Mango参数K₁等成因参数影响不大,伴生原油的这类指标均可以较好地反映天然气的成因类型。蒸发分馏作用对成熟度参数异庚烷值影响较小,而对庚烷值、2,4?DMC₅/2,3?DMC₅值影响明显。轻烃化合物沸点的不同可能是导致天然气与原油中不同类型化合物相对含量存在差异的主要原因,并且沸点较低的化合物在天然气中相对含量更高。组成轻烃参数的化合物的沸点差异越大,该参数受蒸发分馏作用影响越大,天然气与伴生原油的该参数值相差也越显著。而当比值参数中组成分子与分母的化合物的沸点之差小于2 ℃时,该参数基本不受蒸发分馏作用的影响。     

油层水洗级别的热解气相色谱定量判别

应用热解气相色谱资料开展水淹层评价是储层地球化学研究的一个新领域，目前，这方面的研究尚处于定性评价阶段。文章选择位于渤海湾盆地黄骅坳陷的港东油田和羊二庄油田新近系开发层系（包括馆陶组和明化镇组）为研究目的层，以岩心热解气相色谱分析为手段，开展了油层水洗级别的气相色谱定量判别的尝试。在系统分析各气相色谱参数的地质意义及其与油层水洗的关系的基础上，优选出合理的评价参数，并采用交会图技术建立不同级别水洗油层的定量判别标准，通过其他评价方法的验证，表明该定量判别方法具有实际应用价值。     

GEOCHEMICAL CHARACTERISTICS OF CRUDE OILS FROM THE SHARARA-C OIL FIELD,MURZUQ BASIN,SOUTHWESTERN LIBYA

Crude oil samples from the Sharara-C oil field (Concession NC-115, Murzuq Basin, SW Libya) were analysed by organic geochemical methods in order to infer the geochemical characteristics of their respective source rocks. Aromatic hydrocarbons were analysed by gas chromatography – mass spectrometry (GC-MS), and gas chromatography – tandem mass spectrometry (GC-MS-MS) was used to analyse saturated biomarkers. The Sharara-C oils are interpreted to have been generated by marine shales containing mixed terrigenous and marine organic materials deposited in an intermediate (suboxic) environment. Age-specific biomarker ratios indicated that the oils are older than Cretaceous, and maturation-related parameters pointed to their high thermal maturity. Consistent with previous studies, source rocks are inferred to be “hot” shales in the Lower Silurian Tanezzuft Formation. Almost all the parameter ratios calculated varied over a very narrow range, indicating that the investigated oils were compositionally similar. The only significant difference that was noted concerned the sterane/hopane ratios whose variation suggested that there was some variability in the composition of the source organic material. The organic geochemical parameters determined for the Sharara-C crude oils were compared with published data on other crude oils from Concession NC-115. Almost all the parameters agreed well with previously published data on oils from this part of the Murzuq Basin. The greatest deviation concerned the values of some of the maturity parameters. This tended to confirm the conclusions of previous studies concerning the presence of a number of distinct oil families and sub-families in the Sharara oil field area which are genetically related but which have different maturities.     

窑街油页岩热解特性及产物分析

采用铝甑低温干馏和TG-DTG、FT-IR、GC、GC-MS等分析手段研究了窑街油页岩（YJOS）的热解特性及其热解产物页岩油、半焦和干馏气的组成。结果表明,YJOS的最佳热解温度约为510℃,油页岩中的无机质组分一方面对有机质的热解起着催化剂的作用,降低了热解初始温度,同时也因为其与有机质的紧密结合阻碍了热解产物的顺利逸出;半焦中的脂肪烃几乎完全消失,有机质的缩合度和芳香度增加;干馏气的主要可燃成分是H2和CH4,其次是C2H6、CO和C2H4,干馏气的平均相对分子质量约为20.4,平均比热容约为51.9 J/(mol?℃),平均热值约为40.13MJ/ Nm3;页岩油的密度为0.938g/mL,其中饱和烃和芳烃的质量分数分别为35.91%和26.51%,同时还含有较多的含氧、氮、硫等杂原子的有机化合物。     

吉木萨尔页岩油藏泡沫辅助注气吞吐试验研究

吉木萨尔页岩油藏储层渗透率极低,改造后存在大量人工裂缝和天然裂缝,采用注氮气吞吐方式开采易发生气窜,造成氮气波及范围小,页岩油采收率低.为了增大氮气波及范围、提高吉木萨尔页岩油藏的采收率,在评价泡沫封堵页岩裂缝能力的基础上,利用吉木萨尔页岩岩样进行了泡沫辅助注气吞吐试验,分析了泡沫辅助注气吞吐提高采收率的机理,研究了吞...     

油气化探技术预测复杂类型油气藏富集区

为探索寻找复杂类型油气藏富集区的方法，以松辽盆地北部的西部地区为例，列举来36井区、古龙-茂兴地区和古81井区的勘探实例，运用常规化探、放射性热释光和测氡等技术，结合该区已有的钻井、地质和物探资料进行综合分析，对该区岩性和地层油气藏富集区带进行了预测和评价。同时，利用油气化探新方法预测了油气产层的深度，实际效果与预测结果吻合较好。在此基础上，总结了利用油气化探技术在勘探具有多套油气组合、含油错叠连片地区寻找复杂类型油气藏的低成本、高效益方法；给出了对于勘探复杂类型油气藏时应遵循的正确方法和勘探程序；表明将油气化探常规技术方法与新技术、新方法相结合，仍然能够在勘探老区发挥重要作用。     

Bulk Geochemical Characteristics of Crude Oils From Wells in the North Western Desert,Egypt

Abstract

Different oil samples were collected from oil fields in the North Western Desert; namely, Meleiha, Razaak, and North Qarun fields. These oils were analyzed geochemically, including sulfur content, American Petroleum Institute (API) gravity, and gas chromatography The results showed that API gravity and sulfur content indicate that the crude oils have high mature level of marine origin. Distribution of n-alkanes (Carbon Preference Index [CPI], pr/ph, and isoprenoide/n-alkanes ratios) reflects that the oil samples originated mainly from marine organic sources deposited in a reducing environment. This indicates that the oil samples under investigation are well correlated with each other in the western part of the North Western Desert.     

地震属性的油气模式识别

文章介绍了地震属性油气模式识别的方法。计算多种地震属性,进行综合研究,找出对油气比较敏感的地震属性。收集油气井与非油气井的井旁道地震属性组成学习样本,进行神经网络的学习,并利用学习的结果对集集层进行油气预测。     

川西坳陷天井山古油藏油源判识及其与深层油气成藏关系厘定

四川盆地西部坳陷北段天井山古隆起区具有丰富油气显示,古油藏油源示踪与成藏破坏过程厘定对川西坳陷北段深层油气成藏过程与机理研究具有重要意义.天井山古隆起构造解析明确寒武纪—奥陶纪之交的构造事件在川西坳陷北段有显著表现.天井山古隆起的形成是早古生代绵阳—长宁拉张槽形成后构造—沉积性质由拉张转向挤压的重要节点.川西坳陷北段油...     

地面化探识别油气成因

提出了一种新型油气化探指标--成因信息.成因信息指标是通过如下研究步骤获得的:以吸附丝-居里点热解色谱分析为手段,先通过井中化探提取各层源岩的成因“指纹”或特征化合物;后从油气成因单一或以一种成因油气占主导的油气田上方去追寻上述“指纹”,并将所有与之呈“共消长”关系的化合物谱峰合并为某种成因油气的“地面响应特征峰群”;最后用特征峰群分量或“总烃分母剥离法”计算的参数勾画某种成因油气的地面化探异常图.以陕甘宁盆地某气田为例,在其上方勾画了上古生界煤系气、中生界含油和奥陶系腐泥气的异常展布.同时对某油田的扩边勘探提出建议.用成因信息指示油气其意义十分明确.通过油气成因的识别可进一步推测含油气层位或发现新的含油气层系,同时可在多套油气复合地区逐一反映每套油气的异常展布,从而提高了异常叠加情况下资料解释的符合程度.     

塔里木盆地塔中隆起寒武系深层油气地球化学特征及成因

塔中隆起寒武系碳酸盐岩储层油气资源丰富,然而由于复杂的构造地质背景,油气来源和天然气类型还存在较大争议。通过详细分析ZS1井、ZS1C井和ZS5井寒武系不同层段中凝析油和天然气的组成、碳同位素等特征,并结合寒武系-下奥陶统与中、上奥陶统烃源岩地球化学特征,对其油气来源和天然气成因类型进行了判别。研究结果表明,该区天然气为典型的腐泥型干酪根裂解气,其中寒武系肖尔布拉克组天然气干燥系数大于0.98,N₂含量介于2.5%~4.0%,为过成熟干气,且凝析油族组分与和饱和烃单体烃碳同位素偏重,nC₉-nC₂₀碳同位素介于-28.8‰~-26.3‰,表明油气来源为寒武系-下奥陶统烃源岩。而寒武系阿瓦塔格组和吾松格尔组天然气干燥系数介于0.63~0.78,N₂含量介于0.2%~0.8%,为低成熟湿气,且凝析油族组分和饱和烃单体烃碳同位素相对较轻,nC₉-nC₂₃碳同位素介于-37.25‰~-32.56‰,表明油气来源为中、上奥陶统烃源岩。     

页岩气勘探的地球化学指标及测井分析方法初探

页岩气有别于已经大量开采的常规天然气,在成藏机理及赋存特征方面都有其独特的特点,识别页岩气的方法也有别于以往对常规天然气气藏的判别模式。总有机碳含量、成熟度是其重要的判别指标。通过对这些地球化学指标的认识,作为对可用地化分析样品的补充,利用测井资料计算这两个参数将有助于对页岩气藏的识别。总有机碳含量代表了页岩气源岩的生气潜力,成熟度则表现干酪根的演化程度,两者综合指示页岩储层中可能存在的天然气量。     

我国油气化探近几年来的成果与问题

在“八五”科技攻关中,作者系统地研究了我国主要含油气盆地的化探资料,指出以含油气盆地为基本单元研究化探背景值的变化提高了异常的可靠性;建立不同级次化探异常的系统概急是科学地获取油气信息、正确应用化探技术的重要方面;总结了识别天然气的烃类气体特征、光谱参数等6项指标及物化探直接找油气技术;认为井中化探录井技术有广阔的应用前景。      

Geochemical Characterization of Offshore Western Niger Delta Source Rock

Abstract

A geochemical characterization of rock samples obtained from three offshore fields, MJ, MF, and ML, was carried out. Offshore oil and onshore oil samples were also studied for correlation. The gas chromatographic data showed that the three offshore fields studied exhibited different and unique geochemical signatures. Most rock samples from the MJ field have moderate thermal maturity; n-alkane and their isoprenoid hydrocarbon distribution indicated predominant mixed organic matter with some terrestrial organic matter. The organic matters were deposited in alternating oxic and anoxic environments. In the MF field, sedimentation of the organic matter in the shallow depths was under reducing environments, whereas that of the deeper depth horizons was under oxidizing environments. The rock samples in the field had predominant input from marine organic matter with moderate thermal maturity. In the ML field, the geochemical data indicated that oxic conditions prevailed during sedimentation of the organic matter. About half of the rock samples from this field are thermally mature, with almost equal distribution of marine and terrestrial organic facies. Marine organic matter was prevalent in the shallow depth horizons, whereas terrestrial organic matter was prevalent in deeper depth horizons. The offshore oil samples and offshore rock extracts are also correlative. This study indicates that there are two petroleum systems in the offshore western Niger Delta—marine and terrigenous petroleum systems—though the terrigeonous system is more pervasive.