盖层研究现状及发展趋势

从盖层分类、封闭机理和盖层评价等三个方面对国内外盖层的研究现状进行了综述，指出了其发展趋势，即日趋综合化、动态化和定量化。     

全球古生界海相碳酸盐岩大油气田特征及油气分布

古生界海相碳酸盐岩油气对中国能源安全具有重要意义。以全球古生界海相碳酸盐岩大油气田的最新资料为基础,系统统计分析了古生界海相碳酸盐岩大油气田的地质特征及其分布规律。截至2013年底,全球15个含油气盆地中共发现了89个古生界海相碳酸盐岩大油气田,油气可采储量达495.9×10⁸,t油当量,占全球海相碳酸盐岩层系油气总储量的20.9%。研究表明,大油气田分布在中东、前苏联、北美和亚太地区,其中,大油田主要分布于前苏联和北美,大气田则主要位于中东和亚太,20世纪70年代是大气田发现的高峰期。大油气田的油气主要来自古生界烃源岩,以志留系、石炭系、二叠系和泥盆系(按重要性排序)为主;烃源岩岩性主要为泥页岩、沥青质泥页岩和沥青质碳酸盐岩。盖层以蒸发岩和碎屑岩为主。层系上,油气主要富集于二叠系、石炭系和奥陶系,白云岩和生物礁储集层占重要地位。埋深上,储量分布相对集中的埋深为2500~3000,m、3500~4000,m和4000~4500,m,分别占总储量的52.6%、15.9%和9.5%。油气藏类型上,以构造圈闭为主,不过近年来发现的大油气田的非构造圈闭比例有所增大。建议中国古生界海相油气勘探应重视白云岩储集层,更重要的是,应加强深层海相碳酸盐岩层系油气成藏机理和分布主控因素的研究。     

Geodynamics of ophiolites and formation of hydrocarbon fields on the shelf of eastern Sakhalin

A model is proposed showing the formation of hydrocarbon fields on the shelf of eastern Sakhalin as being caused by sustained (from the Late Cretaceous to the present) extension in the adjacent deepwater Deryugin Basin with exposure of the upper mantle rocks at the bottom of the sedimentary basin. The thrust faults and detachments formed through this process facilitated the penetration of seawater into ultramafic rocks, thus providing large-scale serpentinization accompanied by generation of hydrocarbons. Extension in the Deryugin Basin was compensated by horizontal shortening at its margins, and as a result, by the formation of ophiolitic allochthons as constituents of the accretionary prism of eastern Sakhalin. Hydrocarbons were injected and pumped in the root zones of the allochthons, giving rise to their westward migration and the formation of petroleum pools in fault-line and underthrust traps on the shelf of Sakhalin Island. The Deryugin Basin is a petroleum-collecting area for oil and gas fields localized in the upper part of its western margin. More broadly, the work considers interrelations between hydrocarbon generation and the geodynamics of tectonic couples of ophiolitic allochthons and adjacent deepwater basins of marginal seas, in particular, in the western Pacific.     

莺歌海盆地高温高压盖层封盖能力定量评价

莺歌海盆地是我国南海重要的新生代含油气盆地,随着浅层常压层系天然气开发程度的逐渐提高,中深层高温高压层系成为天然气勘探的主要目标,超压背景下盖层封闭的有效性受到广泛关注.近年来,不同学者针对莺歌海盆地盖层进行了大量的研究,但是对高温高压的气藏盖层的封闭机理、破坏条件及其定量评价仍存在一定的问题.通过对莺歌海盆地中深层高温高压层系盖层进行系统的分析,明确盖层的封闭机理为毛细管封闭和水力封闭.利用泥岩盖层排替压力、声波时差及孔隙度之间的关系,对莺歌海盆地区域性盖层的毛细管封闭能力进行预测.莺歌海盆地中深层盖层普遍具有较强的毛细管封闭能力.因此,超压诱发的水力破裂是油气多层位聚集的根本原因,进而提出了盖层水力破裂压力系数定量评价盖层水力破裂风险性.评价结果显示,盖层发生水力破裂与底辟构造活动具有明显的相关性,盖层水力破裂风险由底辟中心向外围逐渐减弱.位于莺歌海盆地斜坡近凹带,且紧邻乐东三大底辟的LD-B区块是油气富集的有利区域.      

塔里木盆地塔中礁滩体大油气田成藏条件与成藏机制研究

中国海相碳酸盐岩油气勘探近年来进展很快,发现了一批大型油气田。塔中地区是塔里木盆地的重点勘探区和富油气区,奥陶系蕴藏了丰富的油气资源。奥陶系良里塔格组受塔中I号坡折带的控制发育陆棚边缘礁滩体,储层性质为低孔-特低孔、低渗灰岩储层,埋深在4500~6500m。储层的形成和分布受早期高能沉积相带、溶蚀作用和断裂作用等因素的控制,有效储层的空间展布控制了油气的分布与大面积成藏。油源对比认为,塔中良里塔格组礁滩体油气藏的原油主要来自于中上奥陶统烃源岩,并混有寒武系烃源岩成因的原油;天然气主要来自于寒武系油裂解气,沿塔中I号坡折带断裂向内充注。成藏过程分析表明,塔中地区曾存在三期主要成藏期,第一期为加里东晚期成藏,油气来自于寒武系-下奥陶统烃源岩,但早海西期的构造运动,对该期油气破坏严重,造成大范围油藏破坏。第二期成藏期是晚海西期,也是塔中地区最重要的油气充成藏期,油气来自于中上奥陶统烃源岩。第三期成藏期是晚喜山期,受库车前陆冲断影响,台盆区快速沉降,埋深急速增大,寒武系原油裂解气形成,沿深部断裂向浅部奥陶系充注,对油藏进行气洗改造,从而形成大面积分布的凝析气藏。     

Application of scattered and emitted seismic waves for improving the efficiency of exploration and development of hydrocarbon fields

The success of drilling oil and gas wells is largely determined by a high hydrocarbon content and reservoir permeability at the point of penetration. Microseismic emission and scattered reflection waves are used for the reliable study of these parameters. The Seismic Location of Emission Centers and Side-View Seismic Location technologies have been developed for the observation, selection, and positioning of waves in a geological environment, which significantly extend the range of problems that are solved during seismic exploration of hydrocarbon deposits. Examples of application of these technologies in the exploration and development of hydrocarbon deposits are described.     

大型火山岩气田成藏控制因素研究——以松辽盆地大型火山岩气田成藏控制因素研究——以松辽盆地庆深气田为例

松辽盆地大型火山岩气藏的发现,揭开了我国火山岩油气藏全面勘探的序幕。本文以油气钻探实践结果为基础,应用地质、地球物理和地球化学相结合的分析方法,探讨了松辽盆地大型火山岩气藏的成藏控制因素。结果表明,气源岩发育区控制气藏的宏观分布范围,气藏与源岩区的横向距离一般小于8km,源岩与火山岩厚度比大于2的区域对成藏尤为有利; 大断裂控制火山岩体呈条带状或串珠状展布,延断裂带火山岩厚度大,最大厚度超过1600m; 火山岩相和火山旋回控制储层发育状况,火山口或近火山口叠合相储层发育,储层厚度一般100~200m,有利储层常发育于火山旋回的顶部; 火山机构中心部位具有局部构造高、储层物形较好、断裂发育等特点,在气源条件优越时,是短距离垂向运移成藏的最有利地区。     

A Study of Stress Change and Fault Slip in Producing Gas Reservoirs Overlain by Elastic and Viscoelastic Caprocks

Geomechanical simulations were conducted to study the effects of reservoir depletion on the stability of internal and boundary faults in gas reservoirs overlain by elastic and viscoelastic salt caprocks. The numerical models were of a disk-shaped gas reservoir with idealized geometry; they mimic the structure of a gas field in the northern Netherlands which has experienced induced seismicity during gas production. The geomechanical simulations identified the area of the internal fault most sensitive to fault reactivation as coinciding with the epicenters of the largest seismic events associated with gas production. Depletion-induced shear slip is initiated at the depth of the reservoir, in the fault areas where the vertical fault throw ranges between 0.5 and 1.5 times the reservoir thickness. The extent of reactivated area differs depending on whether the caprock is viscoelastic or elastic: when it is viscoelastic, there is more down-dip shear displacement. High initial horizontal stresses in the rock salt and lower stresses in the elastic side-seal and the reservoir promote unloading of the internal and reservoir-bounding faults even before the reservoir is depleted. Particularly prone to fault reactivation are the fault zones along the interface between the reservoir rock and the salt caprock, which may already be critically stressed before depletion and are likely to be reactivated early during gas production. Stress relaxation and associated geomechanical changes affecting fault stability and ground surface deformation may continue long after production has ceased, due to the viscous behavior of the salt.     

Uncertainties in hydrocarbon charge prediction

Computer simulations allow the prediction of hydrocarbon volumes, composition and charge timing in undrilled petroleum prospects. Whereas different models may give different hydrocarbon charge predictions, it has now become evident that a dominant cause of erroneous predictions is the poor quality of input data. The main culprit for prediction errors is the uncertainty in the initial hydrogen index (H/C) of the source rock. A 10% uncertainty in the H/C may lead to 50% error in the predicted hydrocarbon volumes, and associated gas–oil ratio. Similarly, uncertainties in the maximum burial temperature and the kinetics of hydrocarbon generation may lead to 20–50% error. Despite this, charge modelling can have great value for the ranking of prospects in the same area with comparable geological histories.     

若尔盖地区酸解烃与热释烃影响因素研究

近地表油气化探影响因素众多,不同地区主导因素也不尽相同。若尔盖地区受复杂地表景观及岩性等因素的影响较大,而且没有已知油气田可供试验研究,可供参考对比的资料也很少,仅仅采用一种技术是不能断言油气信息的真实性、有效性,而是有必要采用不同指标相互补充,相互印证。这里从采样季节、采样深度、岩性、碳酸盐和不同地表景观等因素分析,探讨这些因素对化探指标的影响规律,提出酸解烃和热释烃是适合高原草原地形的合适指标。并给出初步的数据校正方法探讨。     

济阳坳陷沾化凹陷古近系水化学场对湖盆演化的响应及其油气意义*

通过对沾化凹陷古近系1160条数据体的试油资料、原油物性资料的分析,对沾化凹陷古近系沙河街组四段到东营组的水化学场特征进行了研究,结果表明：沾化凹陷古近系水化学场分布特征与湖盆演化的旋回性有良好对应关系,从湖盆的断陷初期阶段到断陷鼎盛阶段（沙河街组四段到三段）,湖盆水体加深及淡化,矿化度及氯离子含量平均值逐渐下降;而在湖盆的总体萎缩阶段（从沙河街组二段到东营组沉积期）,水体总体变浅,矿化度及氯离子含量平均值总体增大。在各阶段,地层水类型均以NaHCO₃型占绝对优势（比例达到80％）,显示了典型的开放型湖盆的地层水场特征。NaHCO₃型地层水主要分布于地层水矿化度较低（<15 g/L）的地层中,指示了水交替活动强烈的开放水文环境,对油气保存不利;而相对较高矿化度（≥15 g/L）的NaHCO₃型地层水主要分布于生烃洼陷（渤南洼陷等）内部及义东断裂构造带附近,其成因主要与油气田形成和高含量的、以深部幔源为主的CO₂气及断裂沟通有关,其对应的原油密度基本小于0.9 g/mL,指示了相对有利的油气保存环境。     

浅层地下水卤代烃污染初步研究

笔者通过对某地区浅层地下水中卤代烃（三氯甲烷、四氯化碳、三氯乙烯、四氯乙烯和三溴甲烷）的测试、研究和分析，阐明了该地区浅层地下水中卤代烃污染物主要是三氯甲烷、三氯乙烯和四氯乙烯，主要污染来源是露天堆放的垃圾场、排污河渠和特殊工业企业；确定了污染源分布和包气带岩性是决定该地区卤代烃污染的两个主要因素，冲洪积扇顶部和潜水－承压水过渡带是卤代烃污染的高浓度区；最后对该地区卤代烃污染物的形成和迁移转化机理进行了初步探讨。     

陆相断陷咸化湖盆地层水化学场响应及与油气聚集关系——以渤海湾盆地东营凹陷为例

东营凹陷古近系水化学场分布与湖盆演化有着良好的对应关系,矿化度从深到浅逐渐降低,体现出沉积环境开放性的增强。高矿化度分布是咸化湖盆重要特征,盐岩溶解、扩散、运移和断裂沟通是其主要成因。在这种高矿化度地层水化学场中主要发育CaCl_2水型,在盆地边缘低矿化度地层水中,以NaHCO_3水型为主,同时发育有少量低—较高矿化度的Na_2SO_4水型和MgCl_2水型。对东营凹陷大量实测地层水及油气性质资料分析表明:东营凹陷CaCl_2水型指示地层封闭性条件较好的还原环境,在该环境中油气藏分布最为广泛,目前发现的高矿化度(100 g/L)油藏与CaCl_2水型相关;低矿化度(10 g/L)NaHCO_3水型指示封闭性条件差、水交替强烈的水文流畅环境,对油气聚集不利,可形成次生油气藏;高矿化度(30～100g/L)的NaHCO_3水型对油气聚集也有利,在该水型中多形成原生油气藏,其成因与地幔高浓度的CO_2运移及断裂通道的沟通作用有关;研究区高矿化度(30 g/L)Na_2SO_4水型的形成与膏盐有关,其中可形成原生油气藏;低矿化度Na_2SO_4水型指示封闭性条件差的氧化环境,对油气聚集不利。研究结果表明,在东营凹陷断陷咸化湖盆中,含NaHCO_3水型的地层环境更能代表地层水交替强烈的开放性沉积环境,而Na_2SO_4水型分布多与硫酸盐有关;东营凹陷表现出高矿化度的NaHCO_3水型和Na_2SO_4水型等异常地层水环境,但在各类型地层水环境中油气藏都有所发现,显示出典型断陷咸化湖盆中水化学场分布特征及与油气成藏之间独特的相互关系。     

Revealing hydrocarbon migration pathways

In this paper a general concept for revealing hydrocarbon migration pathways in rock sequences is introduced. The concept uses a multidisciplinary approach based on a geochemical and a petrophysical (or mineralogical) index. These two indices provide together the migration plot which shows the direction of hydrocarbon movement.With the help of this technique, serrerai hydrocarbon migration effects were established for a sequence of continous cores from the Upper Carboniferous. The results were verified by comparing gradients of hydrocarbon concentrations relative to pore volume. In this way the relative importance of individual migration pathways were recognized, as well as presently or formerly active migration pathways.The strong influence of permeability changes on hydrocarbon movement in source beds requires the use of the »atypical pore network« model to supplement the kerogen network model. Both models help in understanding the mechanisms of primary migration, but in certain stiuations, one might be more effective than the other.

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Zusammenfassung In diesem Aufsatz wird ein Konzept vorgestellt zur Erkennung von Erdölmigrationsbahnen in Gesteinsabfolgen. Das Konzept ist multidisziplinär ausgerichtet und beruht auf der Anwendung eines geochemischen und eines petrophysikalischen (oder mineralogischen) Parameters. Beide zusammen genommen erlauben die Erstellung eines Migrationsdiagramms, das angibt in welche Richtung sich die Kohlenwasserstoffe bewegen.Mittels dieser Methode wurden in einer fortlaufenden Abfolge von Bohrkernen aus dem Oberkarbon mehrere Trends für die Migrationsrichtung von Erdöl erkannt. Diese Trends wurden durch Vergleich mit Kohlenwasserstoffkonzentrationsgradienten, bezogen auf das Porenvolumen des Gesteins, verifiziert. Auf diese Art und Weise ließ sich sowohl die Bedeutung der einzelnen Migrationsbahnen relativieren als auch zwischen jetzigen und früheren Migrationswegen unterscheiden.Der starke Einfluß von Permeabilitätsänderungen auf die Bewegung von Kohlenwasserstoffen auch in Erdölmuttergesteinen fordert die Anwendung des »Atypischen Porennetzwerk-Modells« als Ergänzung zum Kerogennetzwerk-Modell. Beide Modelle tragen wesentlich zum Verständnis der Mechanismen der primären Migration von Erdöl bei, jedoch kann im Einzelfall die Verwendung des einen Modells effektiver sein als die des anderen.

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Résumé L'auteur présente une méthode générale permettant de déterminer le chemin suivi par les hydrocarbures lors de leur migration à travers les roches. Cette méthode utilise une approche multidisciplinaire basée sur un indice géochimique et un indice pétrophysique (ou minéralogique). Ces deux indices combinés fournissent l'indice de migration, qui indique la direction du déplacement des hydrocarbures.Cette méthode a permis d'établir les effets de plusieurs migrations d'hydrocarbure dans une série continue de carottes du Carbonifère supérieur. Les résultats obtenus ont été vérifiés en comparant les gradients du rapport concentration d'hydrocarbure/volume des pores. On peut reconnaître, de cette manière, l'importance relative des voies individuelles de migration, ainsi que celle des voies de migration actives aujourd'hui ou dans le passé.Etant donné le rôle important joué par les différences de perméabilité dans le déplacement des hydrocarbures au sein des roches, on se réfère au modèle Atypical Pore Network, qui complète le modèle Kerogene Network. Les deux modèles sont utilisés de manière complémentaire pour comprendre les mécanismes de la migration primaire; dans des cas extrêmes, l'un d'eux peut être plus effectif que l'autre.Cette approche constitue un nouveau pas vers une meilleure identification et une meilleure quantification des effets de la migration; elle offre des avantages considérables en raison de la diversité des paramètres qui peuvent être utilisés. Comme n'importe quel autre outil d'exploration, elle ne peut être utilisée seule dans les travaux d'évaluation et d'interprétation. Pour porter tous ses fruits, elle doit être intégrée aux données géologiques, géophysiques et surtout hydrodynamiques.

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松辽盆地三肇凹陷青山口组泥岩盖层封闭能力形成时期

泥质岩盖层并非沉积开始就具有封闭油气能力的,而是随其埋深增加,压实成岩程度增强、粘土矿物转化脱水及有机质向烃类演化到一定阶段才开始具封闭油气能力的。本文在对盖层各种封闭能力进行地史恢复的基础上,确定出三肇凹陷青山口组泥岩盖层的毛细管、压力和烃浓度封闭能力开始形成时期分别为青山口组沉积末期、青山口组沉积末期和嫩江组四段沉积末期,都远远晚于上侏罗统气源岩的排气期（侏罗系沉积末期）,因此,造成上侏罗统天     

Causes of geothermal fields and characteristics of ground temperature fields in China

There are many arguments on energy sources and main controlling factors of geothermal fields, so a systematic study on the distribution of ground temperature fields shall be necessary. In this paper the thermal conduction forward method of geothermal field is used to simulate cooling rate of abnormal heat sources and heat transfer of the paleo-uplift model. Combined with a large number of geothermal field exploration cases and oil exploration well temperature curves of domestic and foreign, the following conclusions are drawn:(1) According to the magmatic activity time, the magmatism activities are divided into two categories: Magma active areas(activity time 500 000 years) and weak/magma inactive areas(activity time 500 000 years). The latter has a fast cooling rate(the cooling time of the magma pocket buried around 10 km is less than 200 000 years) after it has intruded into the shallow layer and it has no direct contribution to modern geothermal fields;(2) China belongs to a weak/magma inactive area such as Tengchong region and Qinghai-Tibet region because the chronological data of these regions show that its magma activity time is more than 500 000 years;(3) The temperature of most geothermal fields can be obviously divided into three segments in the vertical direction: A high geothermal gradient segment(Segment H) at the surface, then a low geothermal gradient segment(Segment L) at a secondary depth, and finally a lower temperature segment(Segment D) at a deeper depth. The temperature isoline presents a mirror reflection relation on the temperature profile, indicating that geothermal field is dominated by heat conduction, rather than having an abnormally high temperature "heat source" to provide heat;(4) Near-surface(0-5 km) materials' lateral heterogeneity caused by tectonic movement shall probably be the main controlling factor of ground temperature fields.     

Nonconventional hydrocarbon targets in the crystalline basement, and the problem of the recent replenishment of hydrocarbon reserves

Analysis of the distribution of oil pools in sedimentary cover has shown that known platform hydrocarbon fields are closely associated with faults in the crystalline basement and the sedimentary cover itself. Oil pools in the lower productive beds of the sedimentary cover are linked to faulted zones in the crystalline basement. A genetic relationship between oil fields and tectonic dislocations indicates a dominant role for vertical migration in the accumulation of commercial hydrocarbons in the Paleozoic. The conducted geochemical, palynological, geophysical and geological studies have shown that oil and gas pools in the upper sedimentary cover have been formed due to the vertical migration of hydrocarbons, which is also confirmed by the vertical alignment of the oil pools.