东营凹陷不同超压成因的有效应力特征

利用实测流体压力(DST)测试结果,结合声波和密度测井资料,对超压段所识别的不均衡压实作用和生烃作用两种超压成因机制下的实测压力和有效应力随深度的变化特征进行了分析,结果表明:①两种不同成因机制下的实测压力和有效应力特征具有明显的差异性,不均衡压实作用在压实过程中导致流体排出受阻,地层流体承担上覆岩层压力形成超压,表现为阻止了地层有效应力增大,因此其实测压力增大段和静岩压力增大趋势大体一致,而有效应力随深度基本保持不变;生油作用在地层正常压实之后形成超压,发育程度不受上覆岩层压力的影响,因此超压的增大在深度上与上覆岩层压力增大不具有一致性,且超压对有效应力的影响要小于不均衡压实作用;②这两种不同的超压成因使得有效应力的变化随着声波速度而出现加载和卸载两种趋势,从而可以用来判断超压成因,利用实测资料计算的有效应力结果说明东营凹陷超压成因机制包括不均衡压实作用和生油作用,但不均衡压实作用形成超压的范围和规模较小,生油作用对深部大规模超压和强超压的形成至关重要.     

渤海湾盆地东营凹陷北带油包裹体成分特征

油包裹体成分在油源对比和流体包裹体PVT热动力学模拟具有至关重要的作用。本文采用常规荧光光谱、定量荧光技术和在线压碎群体包裹体成分分析方法对东营凹陷北带沙三段和沙四段砂岩储层样品中的油包裹体成分进行分析。荧光光谱分析结果表明油包裹体荧光颜色从黄色-黄白色-白色-蓝白色到蓝色呈现连续变化特征,主波长范围在445nm至550nm之间,指示了东营凹陷北带捕获的包裹体中油的成熟度从低到高呈连续变化。观察到的发蓝白色荧光的油包裹体荧光光谱主波长均小于500nm,黄色荧光的油包裹体荧光光谱主波长大于500nm。油包裹体荧光光谱参数主波长和Q值反映发蓝白色和黄色荧光的油包裹体中饱和烃、芳烃、非烃含量和API明显不同,发蓝白色荧光的油包裹体中的烃类具有密度相对较小、成熟度较高的特征。定量荧光和群体包裹体成分结果也表明由于发蓝白色和黄色荧光的油包裹体成分不同导致QGF光谱以及TSF参数都具有明显的区别,发蓝白色荧光的油包裹体甲烷含量偏高,而发黄色荧光的油包裹体C₇-C₉含量相对偏高。     

东营凹陷下第三系流体-岩石相互作用研究

盆地内地层流体-岩石相互作用导致储层特征和流体性质发生变化,影响油气藏的形成与分布。本文分析了东营凹陷下第三系地层孔隙流体的化学和动力学特征及其分布规律,根据地层中矿物的组成和结构特征对成岩过程中地层古流体的地球化学特征进行了推测。并通过对典型油田泥岩层和砂岩层中矿物组合及其在地层剖面上的变化规律的实例剖析,揭示了东营凹陷下第三系储层中流体-岩石相互作用的基本特点,在此基础上,建立储层中流体-岩石相互作用的地质/地球化学模型。     

渤海湾盆地东营凹陷示烃成岩作用及其演化特征*

富含有机酸的烃类流体在由泥质烃源岩进入储集层后将发生一系列的示烃成岩反应。研究发现有6类成岩现象与烃类活动密切相关,即酸性烃类流体的溶蚀作用、蒙脱石脱水与伊利石化、碳酸盐矿物的铁离子浸染、沥青—铁核的轨迹、自生高岭石的形成以及耗水、底积碳酸盐胶结层的隔层分布。这些特殊的成岩现象是含油气盆地内特有的标识,对指示油气初次侵入程度、运移的方向与轨迹、工业聚集度以及最终成藏场所的确定具有重要的参考价值。基于所发现的示烃成岩矿物而建立的“含油气盆地碎屑岩成岩演化规律”,对胜利油区复杂油气藏勘探起到了指导作用,也可为今后含油气区储集层的有效性确定提供借鉴。     

渤海湾盆地东营凹陷沙四下亚段地层压力演化与天然气成藏

通过实测压力、泥岩声波时差、流体包裹体古压力恢复,对东营凹陷民丰地区沙四下亚段地层压力的演化特征进行了分析。研究表明,民丰地区地层压力纵向上存在“常压-超压-常压”三段式结构;时间上,沙四下亚段地层压力具有“二旋回波动模式”,即存在“常压-弱超压-常压”和“常压-超高压-常压（弱超压）”的演化过程,其中两次地层超压的形成时间与中深层天然气藏的两期成藏时间相对应,为油气藏的形成提供了动力条件。研究区地层压力的动态演化过程是多因素作用的结果,第一次高压的形成是地层快速沉积产生欠压实的结果,生烃贡献相对较小;第二次超压的形成是烃源岩大量生烃和原油裂解成天然气造成的,沉积作用为辅。由于地温梯度降低、断裂-砂体泄压、饱和气藏深埋等作用的影响,现今民丰地区沙四下储层表现为以常压为主,伴生部分超压的分布特征。     

东营凹陷原油单体烃碳同位素特征及其在油源识别中的应用

为揭示东营凹陷部分复杂成因油气的来源,对该区原油、烃源岩单体烃碳同位素进行精细特征分析与油源追踪。东营凹陷不同成因原油具有不同正构烷烃单体烃碳同位素特征。沙三段淡水成因原油碳同位素曲线分别以nC₁₅、nC₃₂为主峰,碳同位素总体偏重、前峰极其富集13C;沙四段咸水成因原油一般以nC₂₃为分界线,近似呈对称的双峰分布,δ¹³C值较沙三段成因原油的轻。沙三段、沙四段成因原油碳同位素分别与沙三段、沙四段烃源岩的聚类相关。牛庄洼陷沙三中段透镜体岩性油气藏原油单体烃碳同位素值介于沙三段、沙四段烃源岩之间,与沙四段烃源岩及相关原油具有更好的相关性,验证以往关于牛庄洼陷沙三中段隐蔽油气藏原油为沙三段、沙四段成因的混源油观点。东营凹陷南斜坡孔店组原油碳同位素总体相对较轻、近直线型分布,与孔店组烃源岩、黄骅坳陷孔店组成因原油的碳同位素曲线聚类相关,指示其与孔店组烃源岩具有成因联系。在正常油窗范围内,成熟度对东营凹陷烃源岩及相关原油碳同位素的影响较小,后者主要受控于母源与古沉积环境。单体烃碳同位素可以很好地应用于东营凹陷油气成因与油源研究,该方法是对以往生物标志物地球化学研究的补充与深化。     

东营凹陷盐-泥构造的样式和成因机制分析

以地震剖面的精细解释为基础,借鉴典型盐或泥构造的研究成果,文中确立了东营凹陷盐-泥构造样式:盐-泥枕构造、盐-泥滚—滑脱断层簇—滚动背斜构造、盐-泥核背斜—拱顶断层簇构造。区域伸展作用下的重力滑动作用是东营凹陷盐-泥构造的主导成因机制。重力滑动作用表现为触发盐-泥层的聚集—隆升和引起薄皮滑脱作用。由此文中将盐-泥构造演化历程划分为盐-泥枕发育期和滑脱断层—盐-泥滚—盐-泥核背斜发育期。最终建立了东营凹陷盐-泥构造的成因-演化模式。     

Sedimentary Processes and Depositional Characteristics of Coarse-grained Subaqueous Fans along Steep Slopes in a Lacustrine Rift Basin: A Case Study from the Dongying Depression, Bohai Bay Basin, China

Coarse-grained subaqueous fans are vital oil and gas exploration targets in the Bohai Bay basin, China. The insufficient understanding of their sedimentary processes, depositional patterns, and controlling factors restricts efficient exploration and development. Coarse-grained subaqueous fans in the Yong′an area, Dongying Depression, are investigated in this study. These fans include nearshore subaqueous fans, and sublacustrine fans, and their sedimentary processes, depositional patterns and distribution characteristics are mainly controlled by tectonic activity and paleogeomorphology. Nearshore subaqueous fans developed near the boundary fault during the early–middle deposition stage due to strong tectonic activity and large topographic subsidence. Early sublacustrine fans developed at the front of the nearshore subaqueous fans in the area where the topography changed from gentle to steep along the source direction. While the topography was gentle, sublacustrine fans did not develop. During the late weak tectonic activity stage, late sublacustrine fans developed with multiple stages superimposed. Frequent fault activity and related earthquakes steepened the basin margin, and the boundary fault slopes were 25.9°–34°. During the early–middle deposition stage, hyperpycnal flows triggered by outburst floods developed. During the late deposition stage, with weak tectonic activity, seasonal floods triggered hyperpycnal flows, and hybrid event beds developed distally.     

东营凹陷流体动力系统研究

根据东营凹陷地层孔隙流体的压力、盐度以及运移动力和流动样式,划分出3个流体动力系统:静水压力-低压淡水流体动力系统、静水压力低盐度流体动力系统、超压高-中盐度流体动力系统.超压高-中盐度流体动力系统以有效烃源岩、流体超压和盐度较高[ρ(TDS)≥35 g/L]为特征,压力驱动为主导;静水压力低盐度流体动力系统以常压、低盐度[ρ(TDS)=10～＜35 g/L]流体、运移通道和储层特别发育为特征,运移动力为盐度差和浮力;静水压力-低压淡水流体动力系统以静水压力-低压、淡水为特征,运移动力以浮力和重力为主.     

渤海湾盆地东营凹陷现河矿区古近系断裂体系及形成演化

受双重动力背景控制,渤海湾盆地东营凹陷现河矿区古近系伸展与走滑作用叠加明显,明确断裂体系叠加关系对油气勘探意义重大。文章运用高精度地震资料及钻井资料,通过井震结合解释、构造样式识别、断裂活动性定量表征及平衡剖面恢复等技术手段,从断裂类型与组合样式、断裂叠加关系、断裂活动及演化、区域动力学背景等方面开展了深入研究。结果表明:现河矿区古近系发育伸展与伸展-走滑两套断裂体系,伸展-走滑断裂基于先期伸展断裂叠加走滑作用形成。古近系主干断裂存在沙三中期和东营早期两次活动高峰,受控于伸展-走滑应力叠合作用,现河矿区古近系共经历初始伸展阶段（Ek—Es₄）、强伸展阶段（Es₃下—Es₂下）、走滑-弱伸展阶段（Es₂上—Es₁）、再活化伸展阶段（Ed）和定型保留阶段（N—Q）5个主要的断裂演化阶段。      

渤海湾盆地冀中坳陷寒武纪岩相古地理及其演化

冀中坳陷位于渤海湾盆地西部,是发育在华北地台之上的中新生代沉积坳陷,在寒武系主要发育海相碳酸盐岩。从寒武系露头剖面入手,结合钻井地层,建立露头和钻井之间的地层对比格架。对单井相、地震相、连井相的研究表明,冀中坳陷在寒武纪构造活动平缓,各区域的地层厚度差异小。通过野外露头剖面实测、岩心观察、样品分析以及各岩性含量的统计,识别出了台地、缓坡、陆棚等3种相类型。台地相中可以识别出潮坪、局限台地、开阔台地、鲕粒滩、竹叶状砾屑滩等5种类型。潮坪主要指潮上坪和潮间坪,并进一步识别出了潮上泥坪、潮上云坪、潮上云灰坪、潮间灰坪等类型。基于各沉积相类型的分析,建立了冀中坳陷寒武系的碳酸盐岩沉积相模式,并编制了9张岩相古地理图。对古地理的研究表明,冀中坳陷在府君山期开始海侵,发育了局限台地和潮坪;至馒头期、毛庄期海侵进一步发展,主要发育了潮上泥坪;到徐庄期以后,潮坪、鲕粒滩共存,并在张夏期海侵达到高潮。崮山期开始海退,潮坪沉积又开始出现。长山期、凤山期进一步海退,分别发育了竹叶状砾屑滩和潮上云坪、潮间灰坪等。     

Dynamic Systems of Petroleum Accumulation in the Nanpu Depression,Bohai Bay Basin,China

<正>It is significant to distinguish the dynamic systems of petroleum accumulation(DSPA) for the understanding of petroleum accumulation and distribution.According to the formation pressure framework,genetic types of petroleum and characteristics of conduit systems,three dynamic systems of petroleum accumulation were identified in the vertical profile in the Nanpu depression,Bohai Bay basin.The deeper DSPA(including formations Es_3 to Es_2) is a sealed system with high-overpressure and high-mature self-sourced oil.Most of the crude oil in the system accumulated in the periods of late Oligocene(23.5 Ma) and late Pliocene(2.4 Ma).The middle DSPA(including formations Es_1 to Ed_1) is an overpressured half-sealed system with mature or lower-mature self-sourced oil.The accumulation of oil in the system also occurred in the late Oligocene(23.5 Ma) and late Pliocene(2.4 Ma).The shallower DSPA(including formations Ed_2 to Q) is a hydrostatic system with lower-mature aliensourced oil from the middle system.Oil within this system accumulated only in the late Pliocene period.The oil in the shallower system migrated vertically along the faults from the formerly accumulated oil in the middle system by lateral migration along the sandbodies,whereas petroleum accumulation in the deeper system was mainly derived from the system itself by lateral migration along the sandbodies and rarely migrated out of the system.In this case,it seems that the deeper system is a more potential exploration prospect in addition to the other two proved favorable systems.     

Multiple overpressure systems and their relationship with hydrocarbon accumulation in the Qikou Depression of the Bohai Bay Basin,China

Pressure measurements using drill stem tests and estimates from log data calculation indicate that three vertically stacked regional pressure compartments exist in the Qikou Depression of Bohai Bay Basin, N. China. The compartments comprise hydrostatic, upper weak, and lower overpressure systems. Laterally, overpressure (pressure coefficient > 1.2) occurs in the deeper areas and weakens gradually from the centre to the margin of the depression. The accumulation of oil and gas exhibits the interesting characteristics of oil‐bearing layers above gas‐bearing layers in the Qikou Depression. The pattern can be accounted for by the evolution of overpressure system, the maturity process of the source rock and the main fault activity. In the late Dongying Formation (Ed, 30 Ma), the lower overpressure system began to form shape, and the hydrocarbon sources generated a large volume of oil. However, because there was no migration pathway, the oil only accumulated in the original strata. In the late Guantao Formation (Ng, 12 Ma), the gas was generated, the upper overpressure system formed gradually, and the activity of the main fault gradually increased. Then, the overpressure pushed the early gathered oil to flow from the lower overpressure system into the upper overpressure system. Afterwards, the activity of the main fault decreased again and remains weak until now. Thus, later generated natural gas cannot keep migrating along the main fault and can only accumulate in the lower overpressure system. Copyright © 2014 John Wiley & Sons, Ltd.     

渤海湾盆地东营凹陷始新世三角洲供给型重力流地震沉积学研究*

陆相盆地三角洲前端滑塌型重力流砂岩因富含油气而广受关注,其厚度薄、面积较小、期次多,储集层预测难度大,长期以来制约了油气的精细勘探开发。利用全覆盖三维地震资料和已有钻孔信息,对东营凹陷东辛地区始新世三角洲—重力流沉积体系开展了以层序地层学和沉积学研究为基础的地震沉积学研究。研究表明,沙三中亚段对应二级基准面下降背景的三级层序,以6期大规模高位域三角洲(第5准层序组—第10准层序组)的发育为特征。以第8准层序组为例,以四级层序为研究单元落实了来自不同物源的3个三角洲—重力流沉积体系;再根据地层切片进一步分期落实了其内部薄砂岩储集层的空间分布。地层接触关系特殊,地层厚度和岩性的横向变化剧烈,导致三角洲—重力流发育区地震波速纵横向变化较大。基于目的层精细标定的相位调整成为地震沉积学研究的基础,四级层序(而不是体系域或层序)的约束成为保障地层切片等时性的关键。研究结果表明,四级层序约束下的地震沉积学研究,为三角洲前端滑塌型重力流薄砂岩储集层的横向预测提供了有效的技术支撑,也为恢复深水重力流发育区沉积过程、深化重力流沉积规律奠定了基础。     

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.     

济阳坳陷构造样式及其与油气关系

通过对济阳坳陷几何学和一系列钻井和地震资料的综合分析,认为盆区存在伸展式、走滑式、反转式等三种基本构造样式;按几何学和成因学特征,可进一步分为翘倾断块式、滑动断阶式、潜山披覆式、重力背形式、底辟等5种次级构造样式。伸展式是济阳坳陷最重要的构造样式,次级构造样式的发育和演化与地质体在坳陷中的构造位置关系密切：翘倾断块构造大部分形成在坳陷的缓坡带．滑动断阶构主要发育在坳陷的陡坡带,底辟构造常见于坳陷的洼陷带,潜山披覆构造多发育在盆地四周隆起区与洼陷中的潜山带,而重力背形构造大多发育在主断层的下降盘。盆地内的重力构造作用可随着沉积加厚作用的持续或加剧而逐渐增强,发育在济阳坳陷东部地区的一系列雁列式和帚状构造是郯庐断裂强烈走滑剪切作用的结果。研究证实,受早、晚白垩纪之交区域构造背景变化的影响,盆区应力场曾发生过从挤压作用向伸展作用的转换,导致济阳坳陷中的反转构造普遍发育,并具有东强西弱的时空演化规律。因此,走滑剪切式构造是郯庐断裂走滑剪切的结果,而反转式构造则是区域构造背景发生转化的产物。     

东营凹陷王家岗孔店组油气成因解析

东营凹陷南斜坡东段王家岗地区孔店组原油特征明显不同于沙河街组为主的上部层系.孔店组原油具有高含蜡量、低含硫特征;多项生物标志物成熟度指标一致显示其成熟度高于上部层系,反映母源岩相对较高的成熟度.同区沙河街组原油具有相对低蜡、高硫、低熟-中等成熟等相反的特征,表明研究区内孔店组、沙河街组原油为不同成因原油.油-油、油源对比显示孔店组原油既有沙四段烃源岩的典型特征(如高含量伽玛蜡烷),也有沙四段烃源岩不具备而孔店组烃源岩具备的特征(如C29-规则甾烷优势).正构烷烃单体烃同位素δ13C值揭示孔店组原油与沙河街组原油有别,与深层孔店组烃源岩接近.综合研究认为,王家岗地区孔店组原油具有混源性,油气主要来自深层沙四段、孔二段烃源岩.研究区孔店组油气的发现及其与以往发现油气的不同表明深层另一套烃源岩的存在及广阔的深层油气勘探前景.     

Fluid Dynamic Field in Bozhong Depression, Bohai Bay Basin

The physical accumulation process of oil and gas, as thenatural nuids buried in the underground, follows the mechanism of fluid flow dynamics (Tao, 19831 Hubbert, 1953,1940). More and more lines of evidence show that the underground fluid dynamics not only controls hydrocarbon expulsionand accumulation directly, but also influences hydrocarbongeneration and preservation. Therefore, this research has beenpursued with great interests by worldwide petroleum geologists(GOng and Yang, 19993 Ye et…     

Lithology and formation conditions of paleogene rocks in the Dongying Depression (Bohai Bay Basin,China)

The Dongying Depression is one of the largest depressions in terms of hydrocarbon reserves not only within the Bohai Basin, but also in the whole Pacific region. This is related to the inherited pattern of geological evolution, as well as the optimal combination of oil source rocks, reservoirs, and caprocks, which alternate in both lateral and vertical directions. Diversity of the lithofacies composition of Eocene and Oligocene sediments in thick (proluvial, deltaic, fan deltaic, and deep-water) hemipelagic and gravitational deposits in the composition of various fans, predetermined the wide distribution of sandstone and gritstone beds with good filtration-capacity properties. The beds were filled with hydrocarbons that migrated from the adjacent layers of oil shales and clays. The role of the principal reservoirs was played by sandstones, which were deposited in distributary channels of Eocene deep-water fans. The detailed study of these underwater fans will make it possible to expand the reserves of hydrocarbons explored now in the Dongying Basin.     

渤海湾盆地东营凹陷沙河街组页岩油储层微观孔隙特征

通过场发射环境扫描电镜、低温氮气吸脱附实验、高分辨率背散射电子图像定量分析等技术方法,对渤海湾盆地东营凹陷沙河街组页岩油储层的微观孔隙类型、结构特征及孔隙分布进行了系统研究。结果表明:沙河街组页岩油储层微观孔隙类型多样,包括粒间孔、粒内孔、晶间孔、溶蚀孔和晶内孔5类孔隙。有利储集空间为孔径在100~3000nm的孔隙,以粒间孔、粒内孔和溶蚀孔为主。泥岩类和灰岩类孔隙形态包括细颈瓶状(墨水瓶状)和平行板状;白云岩类孔隙形态为平行板状,连通性最好。白云岩类定量面孔率最大且孔隙发育最好,其次为泥岩类,灰岩类较差。影响微观孔隙特征的主要因素包括矿物成分及含量、有机质生排烃和热液作用,其中黏土矿物和泥级颗粒有利于储层微孔发育,方解石的胶结作用和重结晶作用不利于孔隙发育。生排烃产生的有机酸和热液作用增进了次生孔隙的形成。