Hydrocarbon Reservoir Model of Glutenite in the Fourth Member of Shahejie Formation in Northern Dongying Depression

The glutenite in the fourth member of Shahejie Formation(Es^4) in northern Dongying depression straightforwardly penetrated into the muddy bathyal -abyss facies.The conditions of reservoir is very superior:(1) the high quality thick bedded oil source rock is developed very well in the Lijin sag and Minfeng sag of the study area,and it has the higher capability of generating hydrocarbon;(2) the

The coupling of dynamics and permeability in the hydrocarbon accumulation period controls the oil-bearing potential of low permeability reservoirs:a case study of the low permeability turbidite reservoirs in the middle part of the third member of Shahejie

The relationships between permeability and dynamics in hydrocarbon accumulation determine oil- bearing potential （the potential oil charge） of low perme- ability reservoirs. The evolution of porosity and permeability of low permeability turbidite reservoirs of the middle part of the third member of the Shahejie Formation in the Dongying Sag has been investigated by detailed core descriptions, thin section analyses, fluid inclusion analyses, carbon and oxygen isotope analyses, mercury injection, porosity and permeability testing, and basin modeling. The cutoff values for the permeability of the reservoirs in the accumulation period were calculated after detailing the accumulation dynamics and reservoir pore structures, then the distribution pattern of the oil-bearing potential of reservoirs controlled by the matching relationship between dynamics and permeability during the accumulation period were summarized. On the basis of the observed diagenetic features and with regard to the paragenetic sequences, the reservoirs can be subdivided into four types of diagenetic facies. The reservoirs experienced two periods of hydro- carbon accumulation. In the early accumulation period, the reservoirs except for diagenetic facies A had middle to high permeability ranging from 10 × 10-3 gm2 to 4207 × 10-3 lain2. In the later accumulation period, the reservoirs except for diagenetic facies C had low permeability ranging from 0.015 × 10-3 gm2 to 62× 10-3 -3m2. In the early accumulation period, the fluid pressure increased by the hydrocarbon generation was 1.4-11.3 MPa with an average value of 5.1 MPa, and a surplus pressure of 1.8-12.6 MPa with an average value of 6.3 MPa. In the later accumulation period, the fluid pressure increased by the hydrocarbon generation process was 0.7-12.7 MPa with an average value of 5.36 MPa and a surplus pressure of 1.3-16.2 MPa with an average value of 6.5 MPa. Even though different types of reservoirs exist, all can form hydrocarbon accumulations in the early accumulation per- iod. Such types of reservoirs can form hydrocarbon accumulation with high accumulation dynamics; however, reservoirs with diagenetic facies A and diagenetic facies B do not develop accumulation conditions with low accumu- lation dynamics in the late accumulation period for very low permeability. At more than 3000 m burial depth, a larger proportion of turbidite reservoirs are oil charged due to the proximity to the source rock, Also at these depths, lenticular sand bodies can accumulate hydrocarbons. At shallower depths, only the reservoirs with oil-source fault development can accumulate hydrocarbons. For flat surfaces, hydrocarbons have always been accumulated in the reservoirs around the oil-source faults and areas near the center of subsags with high accumulation dynamics.

Division and Characteristics of Shale Parasequences in the Upper Fourth Member of the Shahejie Formation, Dongying Depression, Bohai Bay Basin, China

Shale parasequence analysis is an important part of sequence stratigraphy sudies. This paper proposed a systematic research method for analyzing shale parasequences including their delineation, division, characteristics and origins. The division method is established on the basis of lithofacies. Multi-method analysis and mutual verification were implemented by using auxiliary indicators（such as mineral compositions, geochemical indicators and wavelet values）. A typical shale parasequence comprises a lower interval of deepening water-depth and an upper interval of shallowing water-depth（e.g., a shale parasequence including a high-total organic carbon（TOC） shale-low-TOC limy shale）. Abrupt increases in pyrite content, TOC value, relative hydrocarbon generation potential（（S1＋S2）/TOC）, and wavelet values are indicative of parasequence boundaries. The proposed research method was applied to study the upper fourth member of the Shahejie Formation in the Dongying depression, Bohai Bay Basin. Results show that there were seven types of parasequences developed. A singular and a dual structured parasequences were identified. Three factors controlling the development of the shale parasequences were identified including relative lake level change, terrestrial input and transgression. The development of high-TOC（〉2%） shale parasequences was mainly controlled by biological and chemical sedimentation. The low-TOC（〈2%） shale parasequences were mainly deposited by chemical sedimentation. The diversities of shale parasequences were caused by four major controlling factors including climate, relative lake level change, terrestrial input and emergency（e.g., transgression）.

Formation mechanism of carbonates in the lacustrine muddy shale and it implication for shale oil and gas: A case study of source rocks in Member 4 and Member 3 of Shahejie Formation, Dongying sag

Through analysis of microscopic characteristics,mineral components,elements and isotopes,the genetic mechanism of carbonates in the deep lacustrine source rocks in the upper submember of Member 4 and lower submember of Member 3 of Shahejie Formation in Dongying sag,is well investigated.The results show that four types of carbonates in the deep lake,i.e.,lenticular coarse crystalline carbonate,lamellar micro-fine crystalline carbonate,lamellar cryptocrystalline carbonate and massive cryptocrystalline carbonate.Of which,the lenticular coarse crystalline carbonate is formed by diagenetic recrystallization.For the lamellar micro-fine crystalline carbonate and the lamellar cryptocrystalline carbonate,through the alga photosynthesis,the carbon dioxide(CO_(2))is constantly extracted from water,thus the concentration of CO_(3)^(-2) ion in water increases,and then the CO_(3)^(-2) ion reacts with Ca2+ ion in lake water surface to form the carbonates;the saline water environment is favorable for preservation of carbonate particles which mostly occur in lamellar micro-fine crystalline;in the brackish water environment,the water is deep,and the carbonate crystalline beneath the carbonate compensation depth surface is usually is dissolved,and most of lamellar cryptocrystalline are preserved.The massive cryptocrystalline carbonate is formed by the sedimentary carbonate which transport from shallow water to deep water by gravity flow.To some extent,the carbonates control reservoir property and compressibility of muddy shale in the upper submember of Member 4 and lower submember of Member 3 of Shahejie Formation in Dongying sag,and provide important information for reconstruction of sedimentary environment of the ancient lake.

Space-Time Evolution and Controlling Factor of Fine-Grained Sediments in the Upper Fourth Member of Shahejie Formation, Dongying Depression

Fine-grained rocks（FGR） are the important source rocks and reservoirs of shale hydrocarbon which is the prospect hotspot at present. Widely distributed fine-grained sediments（FGS） of the upper fourth member of Shahejie Formation in Dongying depression are taken as an example to study the space-time evolution and controlling factor of FGS in this paper. Based on the analysis of well cores, thin sections, inorganic and organic geochemistry indicators, FGR are divided into 7 types of lithofacies. Through the study of ‘point-line-plane＇, this study shows that FGS has the characteristics of rhythum, diversity and succession. The first stage is characterized by clayey FGS（massive claystone）. The second stage is characterized by carbonate FGS（low-TOC laminated limestone） and dolomitic FGS（dolomitic-silty shale） formed by transgression. The third stage is characterized by organic-rich carbonate FGS（middle/high-TOC laminated limestone） distributed in cycle. The fourth stage is characterized by FGS mixed carbonate and siliciclastic sediments（calcareous-silty shale）. A variety of space-time evolution of FGS are controlled by multiple factors including tectonism, climate and lake conditions.

Depositional Environment of Es_4~u and Es_3~l Shales Based on Biomarkers from the Boxing Sag of Dongying Depression, East China

The Boxing Sag is located in the southwest of Dongying Depression, southern Bohai Bay Basin of East China. It is one of the main petroliferous sags in the Dongying Depression, and has two major source rocks, namely the upper 4th Member （Es4u） and lower 3rd Member （Es31） shales of Eocene Shahejie Formation, which are the new exploration targets in recent years. In this study, 16 core samples were collected from Es4u and Es31 shales in the Boxing Sag, and the saturate hydrocarbons were analyzed by gas chromatography （GC） and gas chromatography-mass spectrometry （GC-MS）, respectively. The results show that Es4u shale has obvious phytane and gammacerane predominance, higher concentration of tricyclic terpanes and regular steranes, and very low concentration of 4- methly steranes; Es31 shale has pristane predominance, lower concentration of tricyclic terpanes, gammacerane and regular steranes, and higher concentration of 4-methly steranes. The Es4u shale can be further divided into two types based on the distribution of n-alkanes in gas chromatograms： normal distribution and double peak pattern. The biomarker characteristics and sedimentary facies distribution show that Es4u shale was deposited in the saline-hypersaline semi-deep （Type A Es4u shale, sag center） to shallow （Type B Es4u shale, sag edge） lacustrine environments, Es31 shale was deposited in the freshwater-brackish semi-deep-deep lacustrine environments, and the former sedimentary facies maps of Es4u and Es31 in the Boxing Sag are further modified.

Diversity of depositional architecture and sandbody distribution of sublacustrine fans during forced regression: A case study of Paleogene Middle Sha 3 Member in Dongying Sag, Bohai Bay Basin, East China

Currently, the differences in gravity flow deposits within different systems tracts in continental lacustrine basins are not clear. Taking the middle submember of the third member of Paleogene Shahejie Formation(Sha 3 Member) in the Shishen 100 area of the Dongying Sag in the Bohai Bay Basin as an example, the depositional architecture of sublacustrine fans during forced regression and the impact of the fourth-order base-level changes on their growth were investigated using cores, well logs and 3D seismic data. Sublacustrine fans were mainly caused by hyperpycnal flow during the fourth-order base-level rise, while the proportion of slump-induced sublacustrine fans gradually increased during the late fourth-order base-level fall. From rising to falling of the fourth-order base-level, the extension distance of channels inside hyperpycnal-fed sublacustrine fans reduced progressively, resulting in the transformation in their morphology from a significantly channelized fan to a skirt-like fan. Furthermore, the depositional architecture of distributary channel complexes in sublacustrine fans changed from vertical aggradation to lateral migration, and the lateral size of individual channel steadily decreased. The lobe complex's architectural patterns evolved from compensational stacking of lateral migration to aggradational stacking, and the lateral size of individual lobe steadily grew. This study deepens the understanding of depositional features of gravity flow in high-frequency sequence stratigraphy and provides a geological foundation for the fine development of sublacustrine fan reservoirs.

断块油藏注采耦合提高采收率机理及矿场实践

针对渤海湾盆地济阳坳陷东营凹陷古近系断块油藏水驱开发后期流线固定导致注入水无效循环的问题,基于渗流力学和油藏工程原理,通过室内物模模拟和油藏数值模拟,提出了“细分开发层系、轮注轮采”的注采耦合开发调整技术,并验证了该技术可提高采收率的原理。研究结果表明:(1)利用注采耦合开发技术建立的“注入期间的高渗通道与低渗通道吸水量比模型”和“采油期间主流线和非主流线产油量比模型”均揭示了“改变压力场促进渗流场调整,实现均匀注入和均匀采出,扩大水驱波及系数和增加驱油效率”的注采耦合渗流力学机制。(2)注采耦合技术可以实现“扩大波及系数、增加驱油效率”,起到类似“调剖”的作用,高含水期通过此项技术可将低渗透岩心的分流率由1.0%提到18.6%,模型驱替更均衡;经过2个轮次的注采耦合调整,高、低渗透岩心的原油采收率分别提高了10.3%和16.1%。(3)研究区D断块古近系沙河街组沙二段Es236含油小层油藏注采耦合开发数值模拟结果显示,主流线和非主流线驱替更均匀,两者压力梯度极差由2.3下降至1.4。经过3个轮次注采耦合开发调整,沙二段3—6砂层组油藏平均综合含水率下降了3.2%,累计增油1 760 t,提高原油采收率2.1%,增油降水效果显著。

渤东凹陷新生代伸展-走滑叠合断裂时空差异演化模式及控藏效应

以三维地震精细解释为基础,通过构造剖面恢复,系统分析了渤东凹陷新生代伸展-走滑叠合断裂的时空差异演化特征及控藏作用。研究结果表明:(1)渤东凹陷新生代广泛发育以NNE向为主干、NE向为派生、NW向为叠加的伸展-走滑叠合断裂体系,可划分为强伸展-弱走滑断裂和强走滑-弱伸展断裂2类;整体具有深浅分层、南北分段的特征,纵向上,古近系主要发育强伸展-弱走滑断裂,断裂大而稀,新近系—第四系主要发育强走滑-弱伸展断裂,断裂小而密;平面上,同一断裂在不同段的构造组合样式存在差异。(2)研究区新生代伸展-走滑叠合断裂的演化主要表现为北部断裂活动强度“早强晚弱”,中部断裂继承性持续发育,南部断裂活动强度“早弱晚强”;演化模式分为初始断陷(孔店组—沙四段沉积期)、强烈断陷(沙三段—东营组沉积期)和走滑坳陷(馆陶组—平原组沉积期)3个阶段,初始断陷阶段,NNE—NE向强伸展与弱走滑叠合,NE向强伸展-弱走滑断裂为主控,NW向先存断裂活化,分割凹陷;强烈断陷阶段,NNE—NE向强伸展与弱走滑叠合,NNE向强伸展-弱走滑断裂变为主控,NW向断裂活动减弱或停止;走滑坳陷阶段,NNE向强走滑与弱伸展叠合,断裂不控制沉积,但对地层展布具有调整作用。(3)研究区伸展-走滑叠合断裂的发育演化与油气成藏密切相关,整体具有“早期伸展控源、晚期走滑控运、多期叠加控圈”的特征,东部斜坡带是油气运聚的有利区。

古盐度对陆相页岩发育的控制作用:以东营凹陷古近系沙三下页岩为例

陆相优质烃源岩发育大多与湖泊咸化相关,但湖泊咸化对页岩发育的影响仍不清晰。以东营凹陷古近系页岩重点取心井樊42井为例,通过岩石薄片观察、XRD、岩石热解测试、XRF二维元素扫描、微量元素测试等分析,结合有机地球化学测试数据、微量元素含量的垂向变化等,分析不同盐度演化阶段页岩成分、纹层结构、有机质丰度的变化。结果表明,研究区目的层段页岩可划分为5种岩相类型。目的层段环境演化可以划分为5个阶段,受控于气候、陆源输入等因素。古气候在沙三下亚段沉积时期呈现暖湿—相对湿冷—暖湿—相对干冷—相对暖湿的变化特征。陆源输入量呈多期旋回变化。不同类型岩石的沉积环境特征各异,高盐度的湖泊水体营养盐浓度高,具有较高的初级生产力,水体分层强烈,水体循环较弱。氧/盐度跃层位置相对较高,富氧带水深较浅,使得有机质更快脱离氧化环境沉降进入还原性水体,有利于有机质的保存。碳酸盐矿物含量高,且呈纹层状发育于滞水层中。

陆相断陷咸化湖盆细粒沉积地层有机质富集特征及控制因素分析——以东营凹陷沙河街组第四段上亚段纯上次亚段为例

【目的】湖相细粒沉积泥页岩储层“甜点段”的发育与有机质富集密切相关,但目前针对断陷咸化湖盆泥页岩有机质富集控制因素的探究及富集模式的建立等相关研究较少。【方法】东营凹陷沙河街组第四段上亚段纯上次亚段(Es4scs)时期发育典型的陆相断陷咸化湖盆,为深化对研究该区细粒沉积地层有机质富集规律的认识。从沉积学、地球化学、古生物学及分子地层学等方面入手,利用薄片鉴定、X射线衍射、氩离子抛光—扫描电镜、孢粉鉴定、生物标志物色谱—质谱分析等技术手段,运用各项指标详细探究有机质富集的控制因素,建立适用于研究区各环境演化阶段的有机质富集模式。【结果】(1)有机质具有条带状、充填式、分散式等微观赋存状态,母质来源主要为藻类等低等水生生物,在中上部地层出现少量的陆源高等植物来源;(2)沉积环境经历了较浅水半干旱弱氧环境—深水半湿润还原环境—次深水半干旱贫氧环境三个演化阶段;(3)有机质富集的主要控制因素为古气候、古盐度、古氧化还原性、古生产力和沉积速率,而次要控制因素为古水深、陆源输入、火山作用和热液活动。【结论】本次探究了有机质富集的主控因素,建立了适用于陆相断陷咸化湖盆细粒沉积地层的有机质富集模式,研究成果对我国陆相页岩油气勘探开发具有重要意义,即高生产力、还原环境、适宜的盐度和沉积速率主导了高有机质富集,该环境的沉积产物是页岩油气勘探的有利层段。

渤海湾盆地东营凹陷古近系沙河街组页岩储层润湿性及其主控因素

润湿性影响储层页岩油的赋存状态和渗流规律,是评价页岩储层的重要内容。对渤海湾盆地济阳坳陷东营凹陷古近系沙河街组页岩开展接触角测定和自发渗吸实验,定量表征储层的润湿性特征,分析研究润湿性的主控因素,从而对储层进行优选评价。研究结果表明:沙河街组页岩储层孔隙连通性中等,具有斑状润湿特征,总体为水湿-弱水湿。储层润湿性受有机质特征、矿物组成、孔隙孔径大小和页岩油组分控制。有机质和矿物组成对润湿性的影响由固体颗粒本身的界面张力决定。有机质丰度越高,矿物组成中钙质含量越高,储层的水湿性越差,油湿性越好。含油性和页岩油组分改变了液体的表面张力,从而影响储层润湿性。储层含油性越好,原油中极性组分越多,油湿性越好。孔隙结构通过毛细管力作用影响固、液表面的界面张力,进而影响润湿性。储层孔隙孔径越大,水湿性越差,油湿性越好。从润湿性特征评价,纹层状富有机质富钙质页岩的亲油性最好,且在弱水湿条件下页岩油较易富集成藏,相对容易开采,是页岩油勘探开发的有利选择。

东营凹陷西部沙河街组三段上部泥岩中白云岩夹层成因研究

本文以东营凹陷西部沙河街组三段上部泥岩中白云岩夹层为研究对象，通过泥岩及白云岩夹层在岩石学和地球化学等方面对比研究后认为区内白云岩形成于半深湖环境，是湖盆演化过程中特定阶段由于水深条件、古气候条件、水介质条件等均有利于白云石排除动力学和热力学的障碍而从水介质中沉淀形成的原生白云岩。

东营凹陷南斜坡东段沙河街组砂岩输导层连通性量化表征

以东营凹陷南斜坡东段王家岗油田沙河街组二段为重点解剖对象,利用开发动态资料,结合原油全烃气相色谱指纹特征分析,确定了砂岩输导体间的连通性,建立了利用砂地比判定砂体连通性的数学概率模型,并应用该模型量化描述了东营凹陷南斜坡东段沙河街组主要砂岩输导层的连通特征。研究表明,当砂地比低于20%时,砂体间基本不连通;当砂地比大于20%时,砂体间连通的概率随砂地比增加而逐渐变大;当砂地比大于80%时,砂体间完全连通。除王家岗油田、八面河及研究区西南部一带外,沙河街组三段中亚段输导层砂体连通性较差,沙河街组三段上亚段和沙河街组二段输导层砂体间连通性良好。

烃源岩非均质性的控制因素研究——以东营凹陷为例

下第三系沙河街组是东营凹陷最重要的生储组合。通过对沙河街组烃源岩的研究,发现厚度大、分布广的沙四段和沙三段烃源岩在有机质组成和岩性等方面存在多种尺度的非均质性。从宏观到微观系统分析烃源岩的非均质性后发现,沙河街组烃源岩的非均质性明显受其体系域、沉积相带、有机质保存条件和古生产力等多种因素控制。其中,不同的体系域和沉积相带控制了烃源岩的岩性和岩相组合及生、排烃能力,高的古生产力是有机质富集的前提,缺氧还原环境使有机质能够保存的决定因素,同时,局部环境下发育的火山活动,对优质烃源岩的形成也具有重要作用。

东营凹陷沙四中亚段盐湖相烃源岩研究

东营凹陷下第三系沙河街组沙四中亚段蒸发岩十分发育 ,其中与泥岩共生的含盐系地层在胜坨南部及中央隆起带等地区厚逾千米。通过大量样品的分析测试和对这套蒸发岩沉积体系的研究 ,认为沙四中沉积时期湖盆充填呈现出欠补偿的饥饿状态 ,并建立了深水蒸发成盐的沉积模式。蒸发岩夹层中的深灰色泥岩和页岩的地球化学特征充分体现了盐湖沉积环境标志。高盐环境有利于有机质的富集和保存 ,沙四中亚段的灰色泥岩和页岩为东营凹陷的一套有效烃源岩。

特征元素比值在沉积物物源分析中的应用——以东营凹陷王58井区沙四上亚段研究为例

利用Ni/Co、V/Co、Mg/Mn、Mn/Sr、Ba/Mn、Fe/K、Mg/Ca、Ba/Sr、Mg/Al、Al/Na十个特征元素比值,通过分布模式、物源指数、Q型聚类等方法,对东营凹陷王58井区沙四上亚段砂体物源进行了研究。沙四上亚段沉积时期,王58井区存在南北两大物源体系,王58井及其以北地区沉积物主要来自北部物源体系,王斜583和王126井及其以南地区主要为南部物源体系,中部牛114—斜1井一带具有南北混源特点。研究表明利用特征元素比值判别沉积物物源方向,能够有效地避免水动力及成岩作用的影响,更加准确地判断沉积物的物源方向。

陆相断陷湖盆滩坝沉积模式——以东营凹陷古近系沙四上亚段为例

东营凹陷古近系沙四上亚段发育的滩坝沉积主要有砾质滩坝、砂质滩坝和碳酸盐岩滩坝。滩坝的形成与物源存在一定的关系,这种关系主要受物源类型、物源供应强度及水动力等的综合影响。东营凹陷各地区滩坝的宏观分布特征与微观沉积特征存在明显差异。在详细分析沉积特征的基础上,认为东营凹陷主要存在基岩—滩坝沉积体系、正常三角洲—滩坝沉积体系、扇三角洲—滩坝沉积体系和碳酸盐岩滩坝沉积体系,并建立了相应的沉积模式,为该区油气勘探提供了指导。

东营凹陷东营三角洲沙三段中亚段古地貌特征及其对沉积的控制

东营凹陷沙三段中亚段发育9期特征明显的三角洲进积单元,古地貌对三角洲进积单元的控制作用明显。利用东营凹陷丰富的钻井和高精度三维地震数据,采用适用于该区的定量高精度古地貌恢复方法——滨线轨迹法,来重建研究区9期三角洲进积单元的古地貌特征,并揭示古地貌对沉积的控制作用。研究结果表明,东营三角洲在沙三段中亚段沉积时期古地貌整体呈现南缓北陡、斜坡向西迁移的特征。沉积体的分布范围和沉积样式与古地貌特征具有良好的耦合关系:三角洲沉积主要沿着东部和东南部凸起逐渐向湖盆推进,受物源供给能力和古地貌特征的影响,三角洲朵体沿斜坡向西延伸;深洼区主要发育半深湖—深湖相沉积,在坡度较大的斜坡前端沉积物易发生失稳而形成浊积砂体。

泥页岩沉积特征与生烃能力——以东营凹陷沙河街组三段中亚段—沙河街组四段上亚段为例

泥页岩的沉积环境与形成方式都将控制其矿物、有机质特征并影响岩石的生烃潜力。选取东营凹陷古近系沙河街组泥页岩,开展岩石薄片观察、X射线衍射和热解等检测,研究岩石的矿物学特征和有机质特征,解析各类泥页岩成因与生烃能力的差异。研究发现,研究区的块状、纹层状和含石膏构造泥页岩中构造特征各异,矿物成分(碎屑、黏土、碳酸盐矿物和石膏类矿物等)含量变化大,有机质特征也各不相同。综合分析矿物与有机质的特征及组合关系,发现细纹层页岩和断续纹层页岩是以生物作用为主导形成的沉积产物,生烃能力最强;宽纹层页岩和均匀块状泥岩属化学沉积作用的产物,具有较强的生烃能力;含碎屑块状泥岩主要通过机械作用沉积而成,含石膏构造泥岩则在蒸发环境下通过化学沉淀形成,两者的生烃能力较弱。比较东营凹陷沙河街组三段中亚段—沙河街组四段上亚段的泥页岩类型,发现沙河街组三段中亚段和沙河街组四段纯下次亚段以机械和化学作用形成的含碎屑块状和含石膏构造泥岩为主,导致2个层段的生烃能力较弱;沙河街组三段下亚段和沙河街组四段纯上次亚段以生物或化学沉积作用形成的纹层状页岩为主,导致2个层段的生烃能力较强。因此,关注泥页岩矿物和有机质组合关系,从机械、化学和生物等沉积方式差异的角度探讨各类泥页岩的成因和生烃能力的变化,能够为非常规油气勘探提供新的思路。