A method for evaluating paleo hydrocarbon pools and predicting secondary reservoirs:a case study of the Sangonghe Formation in the Mosuowan area,Junggar Basin

Taking the Jurassic Sangonghe Formation in the Mosuowan-Mobei area of the Junggar Basin as an example, this paper provides a method that evaluates paleo hydrocarbon pools and predicts secondary reservoirs. Through Quantitative Grain Fluorescence （QGF） experiments, well-tie seismic correlation, and paleo structure analysis, the scale and distribution of paleo hydrocarbon pools in the study area are outlined. Combining current structural features and fault characteristics, the re-migration pathways of paleo oil and gas are depicted. Based on barrier conditions on the oil re-migration pathways and current reservoir distribution, we recognize three types of secondary reservoirs. By analyzing structural evolution and sand body-fault distribution, the major control factors of secondary reservoirs are specified and, consequently, favorable zones for secondary reservoirs are predicted. The results are mainly as follows. （1） In the primary accumulation period in the Cretaceous, paleo hydrocarbon pools were formed in the Sangonghe Formation of the Mosuowan uplift and their size and distribution were extensive and the exploration potential for secondary reservoirs should not be ignored. Besides, paleo reservoirs were also formed in the Mobei uplift, but just small scale. （2） In the adjustment period in the Neogene, traps were reshaped or destroyed and so were the paleo reservoirs, resulting in oil release. The released oil migrated linearly northward along the structural highs of the Mobei uplift and the Qianshao low-relief uplift and then formed secondary reservoirs when it met new traps. In this process, a structural ridge cooperated with sand bodies and faults, applying unobstructed pathways for oil and gas re-migration. （3） The secondary hydrocarbon pools are classified into three types： low-relief anticlinal type, lithologic pinch-out type and fault block type. The distribution of the first type is controlled by a residual low uplift in the north flank of the paleo-anticline. The second type is distributed in the lithologic pinch-out zones on the periphery of the inherited paleo uplift. The third type is controlled by fault zones of which the strikes are perpendicular to the hydrocarbon re-migration pathways. （4） Four favorable zones for secondary reservoirs are predicted： the low-relief structural zone of the north flank of the Mosuowan paleo-anticline, the fault barrier zone on the western flank of the Mobei uplift, the Qianshao low-relief uplift and the north area of the Mobei uplift that parallels the fault zone. The study above effectively supports the exploration of the Qianshao low-relief uplift, with commercial oil discovered in the Qianshaol well. Besides, the research process in this paper can also be applied to other basins to explore for secondary reservoirs.

Extensional Tectonics, Rifting, Formation of Sedimentary Basins, Cretaceous Volcanism, Emplacement of Dyke Swarms and Development of Hydrocarbon Pools: Case Studies from Peninsular India and Indian Ocean Region

Prolonged extensional regime in peninsular India resulted in formation of rift and grabens,elongated basins and Gondwana sedimentation along them.Downward progression of rift related faults caused decompression

Possible origin of inert gases in hydrocarbon reservoir pools of the Zindapir Anticlinorium and its surroundings in the Middle Indus Basin, Pakistan

The natural gas in several gas fields in Pakistan is associated with varying percentages of inert gases（e.g.,CO;, N;, and H;S）. The heating capacity of such natural gas is measured in British thermal units（BTU） in Pakistan and is based on the combustion of the natural gases. The study area of this work belongs to the Middle Indus Basin, which also covers some parts of the Sulaiman Foldbelt and the Punjab Platform.Petroleum wells drilled in the study area contain inert gases（mostly CO;and N;） in varying percentages,which decreases the BTU value of sweet gases and the economic value of the gas reserves.Attempts were made to analyze the varying compositions of inert gases（mostly CO;and N;） along the deep-seated basement faults in the Zindapir Anticlinorium, eastern Sulaiman Foldbelt, but no specific relation could be established. Similarly, geothermal gradient zones were identified and the distribution of inert gases in these zones was studied, but even so, no well-established relation could be tracked.However, variations in the amounts of inert gases in the Chiltan Limestone of the Rodho Structure and the Afiband Structure point to the generation of in situ inert gases because both wells were drilled on the same anticlinorium and share the same geology, and possibly, the same source rock. Post-accumulation changes probably play an important role in the generation of in situ inert gases in varying concentrations.H;S is also present in some parts of the Indus Basin. Therefore, a brief discussion about the possible origin of the H;S is also included in this paper.

Formation Dynamics and Quantitative Prediction of Hydrocarbons of the Superpressure System in the Dongying Sag

Based on the theory of formation dynamics of oil/gas pools, the Dongying sag can be divided into three dynamic systems regarding the accumulation of oil and gas： the superpressure closed system, the semi-closed system and the normal pressure open system. Based on the analysis of genesis of superpressure in the superpressure closed system and the rule of hydrocarbon expulsion, it is found that hydrocarbon generation is related to superpressure, which is the main driving factor of hydrocarbon migration. Micro fractures formed by superpressure are the main channels for hydrocarbon migration. There are three dynamic patterns for hydrocarbon expulsion： free water drainage, hydrocarbon accumulation and drainage through micro fissures. In the superpressure closed system, the oil-driving-water process and oil/gas accumulation were completed in lithologic traps by way of such two dynamic patterns as episodic evolution of superpressure systems and episodic pressure release of faults. The oil-bearing capacity of lithologic traps is intimately related to reservoir-forming dynamic force. Quantitative evaluation of dynamic conditions for pool formation can effectively predict the oil-bearing capability of traps.

Enhancement of catalytic and anti-carbon deposition performance of SAPO-34/ZSM-5/quartz films in MTA reaction by Si/Al ratio regulation

In order to further improve the catalytic performance of zeolite catalyst for methanol to aromatics(MTA)technology, the double-tier SAPO-34/ZSM-5/quartz composite zeolite films were successfully synthesized via hydrothermal crystallization. The Si/Al ratio of SAPO-34 film was used as the only variable to study this material. The composite zeolite material with 0.6Si/Al ratio of SAPO-34 has the largest mesoporous specific surface area and the most suitable acid distribution. The catalytic performance for the MTA process showed that 0.6-SAPO-34/ZSM-5/quartz film has as high as 50.3% benzene-toluenexylene selectivity and 670 min lifetime. The MTA reaction is carried out through the path we designed to effectively avoid the hydrocarbon pool circulation of ZSM-5 zeolite, so as to improve the aromatics selectivity and inhibit the occurrence of deep side reactions to a great extent. The coke deposition behavior was monitored by thermogravimetric analysis and gas chromatograph/mass spectrometer, it is found that with the increase of Si/Al ratio, the active intermediates changed from low-substituted methylbenzene to high-substituted methylbenzene, which led to the rapid deactivation of the catalyst. This work provides a possibility to employ the synergy effect of composite zeolite film synthesizing anti-carbon deposition catalyst in MTA reaction.

The distribution and geological significance of carbazole compounds in Silurian paleo-pools of the Tarim Basin, Northwest China

The results presented in this paper indicated that the carbazole-type compounds have high thermal stabil- ity and also show stability in oxidation and bio-degradation. This kind of compounds still has high concentrations and a complete distribution in the analyzed dry asphalt samples, showing that they are particularly useful in the study of hydrocarbon migration of the paleo-pools. The difference in the contents of nitrogen compounds in the Silurian dry asphalts from the Awati, Tabei and Tazhong areas is attributed to the difference in the extent of oxidation and (or) bio-degradation for the areas; the Awati and Tabei areas underwent relatively strong oxidation and bio-degradation. During the first stage of hydrocarbon pool formation in the Silurian system in the Tazhong and Tabei areas of the Tarim Basin (at the end of the Silurian period) and at the second stage in the Awati area (in Permian), the hydrocar- bons experienced a long-distance migration.

Origin of Oils in“Subtle pools”in the Dongying Depression,Bohai Bay Basin, China

Subtle traps or oil pools have become an important exploration play in the Dongying Depression, Bohai Bay Basin, east China. Despite recent successes in exploration, the formation mechanisms of subtle traps are still not well understood. The majority of subtle oil pools in the Dongying Depression are developed in the middle interval of the Es3 Member of the Paleogene Shahejie Formation with the subtle traps being primarily of lenticular basin-floor turbidite sands encompassed in mudstones. Oil in the subtle traps was previously thought to have migrated directly from the surrounding source rocks of the same formation （Es3）. Detailed geochemical investigation of 41 oils and 41 rock samples from the depression now indicates that the oils from the subtle traps cannot be correlated well with the surrounding Es3 source rocks, which are characterized by high Pr/ Ph （〉1）, low Gammacerane/C30hopane, representing a freshwater lacustrine setting. In contrast the oils features low Pr/Ph （〈1） and relatively high Gammacerane content, showing a genetic affinity with the underlying Es4 source rocks, which also have the same qualities, indicating a brackish lacustrine setting. Oils in the Es3 subtle traps are probably derived from mixed sources with the contribution from the upper Es4 source rocks predominating. Therefore unconventional oil migration and accumulation mechanisms need to be invoked to explain the pooling of oils from the ES4 source rocks, which probably came through a thick low interval of the Es3 source rocks with no apparent structural or stratigraphic pathways. We suggest that the subtle oil migration pathway probably plays an important role here. This finding may have significant implications for future exploration and the remaining resource evaluation in the Dongying Depression.

基于水成膜泡沫叠加灭火法的油烃池火处置效能试验

为检验水成膜泡沫(AFFF)叠加灭火法的可行性,通过油烃池火扑救试验,分别对比不同风向和泡沫流量下AFFF叠加灭火法的灭火效能,油池燃烧过程由热成像设备实时记录。结果表明:相较于非AFFF叠加的灭火方法,AFFF叠加灭火法处置油池火的整体效能较高,符合油池火扑救要求。AFFF叠加灭火法具备如下优势:对泡沫灭火剂通用性强,灭火所需的低倍数、中倍数AFFF均可使用低倍数AFFF原液调制;具有良好的灭火性能,能够克服AFFF热稳定性不足的缺陷、提升AFFF的覆盖效果;能够提升泡沫延展性,使泡沫叠层达到油池远端的铺展覆盖。该灭火战术对处置燃烧面积较大的平面流淌火灾具有积极意义。

溶洞充填物判识的频率差异分析技术

寻找碳酸盐岩油藏的关键就是要找到充满流体的大型溶洞。塔河油田的勘探实践表明 ,应用频率差异分析技术可以有效的鉴别溶洞充填物的性质。当溶洞全为流体充填时 ,其地震波具有强振幅、低速度及调谐性的特征 ;当充填粘稠的半流体时 ,其调谐反射相当于绝对反射的 90 ;当充填物为疏松沉积物时 ,其调谐反射也相当于绝对反射的 77 。以上几种介质 ,都很有可能是油的储集体。对于主频集中在 2 0～ 30Hz的反射波而言 ,只要溶洞高度在 2～ 3m以上就能识别。该技术在塔河油田进行了应用 ,其连片三维区溶洞分布层及纵、横向连通情况清晰可见 ;在S4 8井中的风化面下 ,发现了

东营凹陷西部潜山油气藏特征

东营凹陷西部发育太古界、古生界及中生界潜山。受郯庐断裂活动的影响 ,潜山在平面上呈带状分布 ,自东南向北西形成了NW向潜山构造带 ;自西南向北东形成了NE向潜山构造带。新生界的沙河街组、孔店组及中生界和古生界的石炭二叠系的烃源岩为潜山油气藏的主要油源。储集层由太古界变质岩和下古生界碳酸盐岩组成 ,平均孔隙度多在 1 4 ～ 5 0 之间。石炭 -二叠系、第三系及中生界下侏罗统构成潜山油气藏的 3套盖层。根据圈闭类型的差异 ,潜山油气藏分为潜山顶部及内幕两种类型。烃类潜山油气藏多分布于近源的断裂带附近 ,而非烃气往往沿深大断裂、火山通道向上运移 。

“油气成藏模式”的概念、研究现状和发展趋势

通过对国内外油气成藏模式典型实例的剖析,对同类实例的共性进行了概括和简化,将油气成藏模式归纳为5大类,进而提出了油气成藏模式的新定义。研究认为,油气成藏模式分析的要素包括油气藏形成的基础条件、动力介质、形成机制和演化历程等,成藏模式应是基于全部要素的复合分析,但各类成藏模式的建立方法和适用范围应与不同的勘探程度和研究程度相适应。在实际工作中,可根据资料的情况,以4种要素中的一种或多种为主线,兼顾其他要素,来分别建立盆地级、坳陷级、凹陷级或圈闭级的成藏模式。

准噶尔盆地克拉美丽气田油气源特征及成藏分析

通过对新疆准噶尔盆地克拉美丽气田烃源岩特征、油气来源以及天然气成藏过程的分析,并利用烃源岩分析技术、油气源对比技术和成藏综合分析技术等方法解释了克拉美丽气田的主力气源岩,初步明确了气田的成藏过程和形成主控因素。研究认为克拉美丽气田主力气源岩为石炭系烃源岩,油气成藏以近源为主,具有"早期聚集、晚期保存"的成藏过程,油气成藏经历了海西晚期、印支晚期和燕山中期的多期油气充注,不同地区油气成藏具有时序性。石炭系烃源岩展布、火山岩体展布和二叠系乌尔禾组区域盖层是克拉美丽大气田成藏的主控因素。

南堡凹陷的含油气系统分析

根据油 岩对比分析 ,南堡凹陷存在两个已知的含油气系统 :(1)沙河街组含油气系统 ;(2 )东营组含油气系统。前一含油气系统在东营组沉积末时 ,沙河街组三段的烃源岩开始生烃 ,形成自生自储型原生油气藏 ,明化镇组沉积末 ,烃源岩二次生油 ,除形成原生油气藏外 ,还形成了上第三系次生油气藏 ;后一含油气系统在明化镇组沉积末时 ,东营组三段烃源岩在高柳断层以南开始生烃 ,形成东营组自生自储型油气藏及上第三系次生油气藏 ,而在高柳断层以北 ,烃源岩尚未开始生烃 ,不能形成含油气系统。因此 ,在南堡凹陷进行油气勘探时 ,高尚堡及柳赞地区 ,应以寻找沙河街组含油气系统的油气为主 ;北堡和老爷庙地区以寻找东营组含油气系统的油气为主。

塔中奥陶系碳酸盐岩油气成藏机理

在塔里木盆地塔中Ⅰ号构造带发现了目前中国最大的奥陶系生物礁型碳酸盐岩凝析气田,为没有明显边底水、油气水分布复杂的非常规油气藏。研究了其油气成藏地质条件和油气成藏机理。结果认为:目前发现的油气主要分布在上奥陶统良里塔格组大型镶边台地边缘礁滩相中,礁滩体储层纵向叠置、横向连片,沿台地边缘大面积分布,低孔低渗储层的储集空间以次生溶蚀孔洞为主;塔中Ⅰ号构造带历经多期油气充注与调整,油气成藏系统生储盖组合配置优越,储层是油气富集的主控因素;低孔低渗碳酸盐岩储层的非均质性是油气赋存差异的基础,多期油气充注是油气水分布复杂化的重要原因,晚期气侵则是形成非常规凝析气藏的重要机制,多期油气充注与储层非均质性造成了油气产出的复杂性。

南堡凹陷周边凸起地区碳酸盐岩古岩溶与油气成藏

通过地层对比、野外露头剖面观测、单井岩心观察,样品测试等手段,对南堡凹陷周边凸起地区的岩溶作用、成岩作用、油气成藏及控油因素进行了详细研究。结果发现,该区的岩溶作用较为发育,主要为:①野外露头见大的溶洞,岩心观察有岩溶角砾、溶蚀孔洞及黄铁矿集合体等;②录井表现为钻时突然降低甚至钻具放空,井漏;③测井解释有大型溶蚀孔洞发育带、溶蚀孔洞发育带等。成岩作用分为建设性成岩作用、破坏性成岩作用以及双重性成岩作用。油气藏类型主要有潜山不整合油气藏和构造块状油气藏,控制油气成藏的关键因素是岩溶缝洞型储层有效储集体发育程度、烃源岩的好坏及与构造的关系,尤其是油气运移通道是否发育直接影响了周边凸起有利部位的油气富集程度。

珠江口盆地珠三坳陷油气成藏模式与分布规律

珠江口盆地珠三坳陷是一个典型的南断北超的箕状断陷,属于边缘海盆地,具有丰富的油气资源。受到主干断裂的强烈控制作用,该坳陷可以划分为3个石油系统,分别为文昌A凹、B凹和C凹石油系统。在不同的构造部位发育不同的油气藏类型:在缓坡带和周边隆起带上发育潜山或潜山披覆油气藏,局部发育地层超覆油气藏;在主干断层附近发育岩性-构造油气藏;在陡坡带发育扇三角洲前缘滑塌体隐蔽油气藏;在盆地中心位置,可发育远源浊积扇透镜状油气藏。其中,缓坡带的地层不整合-岩性油气藏和盆地中心远岸浊积砂体形成的透镜体油气藏应该是最为有利的近期勘探目标。

我国海相地层膏盐岩盖层分布与近期油气勘探方向

以"勘探反演"的思路,总结了近年来膏盐岩下油气勘探研究的现状,分析了膏盐岩盖层的分布特点,讨论了我国膏盐岩下海相地层的勘探潜力与方向。研究认为,膏盐岩是优质盖层,在我国四川和塔里木两大盆地的海相地层中分布广泛;膏盐岩下油气资源潜力大,是我国未来油气勘探的重点领域。在南方地区,除白垩-古近系外,膏盐岩盖层分布的层位主要有中-下寒武统和中-下三叠统。膏盐岩盖层平面上分布范围很广,但不同地区分布差异性大。其中,中-下三叠统膏盐岩盖层与四川盆地油气分布关系密切;寒武系和中-下三叠统膏盐岩盖层较厚,对海相油气的封盖能力最强。石炭系在湖南中部地区已有一定范围分布。塔里木盆地也发现和落实了多套膏盐岩盖层。在塔里木台盆区最主要的盖层有两套,即寒武系膏盐岩层和石炭系中上部膏盐泥岩层,同样显示出优越的封盖条件。特别是石炭系,是塔里木台盆区最主要的区域性盖层;寒武系膏盐岩盖层在巴楚-麦盖提地区分布面积广,连续厚度大。综合考虑膏盐岩下油气成藏的地质条件,特别是斜坡带、枢纽带的控油气作用,提出了南方和塔里木盆地2个地区5个领域或区带为近期有利勘探区。其中,四川盆地3个领域或区带,分别是三叠系膏盐岩下镇巴区带、寒武系膏盐岩下川南区带和寒武系膏盐岩下鄂西渝东区带;塔里木盆地两个领域或区带,分别是寒武系膏盐岩下巴-麦区带和石炭系膏盐岩下勘探有利区带。

中国南方古隆起对中、古生界原生油气藏的控制作用

乐山—龙女寺、黔中及江南隆起主要控制了上震旦统及下古生界原生油气藏的发育,泸州、开江隆起及南盘江—十万大山地区的晚古生代—三叠纪(孤立)台隆控制了上古生界及三叠系原生油气藏的分布。南方古隆起均被不同程度地改造,使完整的隆起面貌已不复存在。南方现存的中、古生界原生油气藏很少,四川盆地的早期原生油气藏绝大多数被改造变成了次生气藏,四川盆地以外的扬子区及华南区的原生油气藏则基本被破坏成为古油藏。提出南方中、古生界油气勘探应主要考虑次生油气藏及再生烃油气藏的勘探,上扬子地区主要考虑次生气藏的勘探,中、下扬子地区主要考虑再生烃油气藏的勘探。文中还指出了具体油气勘探有利区,并已经得到苏北盆地盐城凹陷朱家墩气田及江汉盆地沉湖地区南部开先台西含油构造勘探发现的证实。

深大断裂在油气藏形成中的作用

纵观我国东部裂谷系中松辽、渤海湾、江汉及南海等几个重要的含油气盆地发现油气田的分布与盆地中断开基底、地壳或岩石圈的深大断裂有相伴出现的现象，分析深大断裂与沉积、构造、地温场及压力场的相关性后发现：深大断裂控制了沉积体系及沉积相带的展布；控制了地温场的展布；从而控制了油气藏形成条件的生、储、盖因素。深大断裂还控制了盆地内构造区带的展布、控制了流体压力场的展布，从而控制了油气藏形成条件的运移与聚集因素。因此，深大断裂控制了含油气盆地中油气藏的分布；查清深大断裂的分布是提高勘探成功率的重要途径。

准噶尔盆地玛湖凹陷东斜坡深层成藏领域研究

为深化准噶尔盆地玛湖斜坡区的油气勘探,通过分析成藏特征与有利条件,研究了东斜坡地区深层的油气成藏和勘探新领域。结果发现,二叠系/三叠系不整合界面上下是油气成藏和勘探的重要目标,其目的层系油质轻、保存条件好、存在有利相带与相对优质储层,因而具备形成高产的潜力,并可能主要位于扇三角洲前缘亚相。通过单井相、地震相分析和井震结合等方法,预测了有利相带的空间分布及主要发育的圈闭类型,发现有利勘探面积大,岩性—地层圈闭广泛发育,且当前勘探程度低,故勘探前景广阔,可望开辟勘探新领域,值得在下步勘探中加强探索。