渤海湾盆地渤中凹陷BZ26—2—1井馆陶组原油两期注入史

渤中地区普遍存在油气多期运聚成藏。BZ26—2—1井馆陶组原油样品的地球化学分析表明,该原油具有降解和未降解的双重特征：①正构烷烃系列分布完整,且丰度高;②GC／MS分析检出相当丰富的25．降藿烷系列,且绝对浓度较高。这一现象表明馆陶组原油至少存在两期充注过程。     

河南省东濮凹陷古近系沙河街组沙三段盐岩沉积特征及其石油地质意义*

东濮凹陷是渤海湾裂谷盆地西南缘临清坳陷的一部分,和其他凹陷相比有一个显著的特征就是盐岩十分发育。东濮凹陷北部中央隆起带及周边沙三段自下而上发育了3套大的盐韵律,每套盐韵律又由若干个小盐韵律组成。在岩盐富集的地区是油田的主力产油区,油气富集与岩盐有着密切关系。通过对岩盐层岩心、测井及地震资料进行分析,总结出了盐岩的岩性、电性及地震响应特征;岩性变化为砂泥岩→含膏泥岩→膏盐→盐岩→膏盐→含膏泥岩→砂泥岩演化规律;电性主要表现为极低密度、极低自然伽马、很高电阻率及淡水钻井液扩井径等特殊电性特征;在地震剖面上常表现为强振幅、低频率的响应特征。在分析研究盐岩发育特征的基础上,总结出了盐岩的时空展布规律,同时对盐岩与烃源岩、储集层及盖层的关系进行了探讨,根据实际生产和盐岩的沉积规律对生储盖组合进行了分级。得出生、盖为同一层及生、储、盖在不同的空间与盐岩层有关的生储盖组合关系模式,在此基础上总结了东濮凹陷含盐地层油气成藏模式,明确了盐岩的石油地质学意义,对老油田的滚动勘探具有指导作用。     

Recovery of the Erosion Thickness and Characterization of the Paleogeomorphology in the Southern Lishui Sag,East China Sea Shelf Basin

The restoration of the denudation thickness is the basis for quantitatively analyzing the basin burial history,thermal evolution history and hydrocarbon accumulation conditions.The well data is not sufficient to do this in the southern Lishui Sag with only 5 wells,so the new,high-quality three-dimensional(3D)seismic data is essential.The methods employed to determine the eroded thicknesses of key unconformities in the study area are the mudstone acoustic time difference(AC)method,vitrinite reflectance(Ro%)method and stratigraphic trend comparison method.On the basis of the structural evolution,the restoration of the paleogeomorphology is carried out.The results show that the Wenzhou formation(E2 w)in the entire study area has been all denuded.The denudation thickness is in the range of 0–550 m,and decreases gradually from west,thicker than 200 m,to east.The erosion of the upper Lingfeng formation(E1l)are mainly occurred in the N-P-1 structural trap(N-P-1),the N-P-2 structural trap(N-P-2)and the N-P-3 structural trap(N-P-3).Among them,the eroded area in N-P-1(near well S-1)and N-P-2 is 200–230 km^2,and the denudation thickness is 0–600 m,which increases from south to north,even up to 200–400 m in the region around well S-1.In N-P-3,the extent of denudation is 30–50 km^2,and the denudation thickness is 0–400 m.In the early stage of the upper E1 l,one north-south strike slip fault began to develop in the southern study area.Affected by this fault,the southern Lingfeng bulge was offset,forming a gorge,and the eastern and western sides of the concave belt connected to each other.On the basis of the paleo-geomorphological characteristics,it is shown that the sedimentary center of the west subsag began to migrate to the south.     

Quantitative evaluation of the reservoir potential and controlling factors of semi-deep lacustrine tempestites in the Eocene Lijin Sag of the Bohai Bay Basin,East China

Ancient lacustrine storm-deposits that act as petroleum reservoirs are seldom reported. The Lijin Sag, which is located in the southeastern corner of the Bohai Bay Basin in East China, is a NE–SW trending Cenozoic half-graben basin. Some of its Eocene deposits (Bindong deposits) were interpreted as lacustrine tempestites. The Bindong tempestites, which developed in the lower part of the upper fourth member of the Shahejie Formation (Es4¹), constitute a new kind of petroleum reservoir and are novel petroleum exploration targets in the Bindong Area. However, the characteristics of the Es4¹ Bindong tempestite reservoirs and their controlling factors are poorly understood. Point-count analyses of thin sections, scanning electron microscope image analyses, X-ray diffractometry data, and the petrophysical parameters of the Bindong tempestite reservoirs were utilized to estimate the reservoir quality. The reservoirs have undergone significant diagenetic alteration, which can be divided into negative and positive aspects. The negative alteration includes compaction, authigenic minerals, and cementation such as carbonates, clay minerals and overgrowths of quartz and feldspar. The uneven distribution of carbonate cement increased the reservoir’s heterogeneity, with carbonate cement commonly precipitating along the sandstone-mudstone contacts. The primary porosity was severely reduced because of compaction and extensive carbonate cementation. Positive alteration includes dissolution, carbonate cementation, undercompaction and fractures. Carbonate cementation exhibited both positive and negative effects on the reservoir quality. Overall, the objective reservoir quality is quite poor. A quantitative evaluation of the reservoirs’ potential was conducted. The cutoff values of several of the reservoir’s parameters were calculated. The lower limits of the porosity and permeability are 8.35–5.85% and 1.2587–0.2753 × 10^–3 μm², respectively, depending on the depth. The upper limits of the carbonate and mud content are approximately 18.5% and 9–10%, respectively. A fundamental understanding of these characteristics will provide necessary information for extracting hydrocarbons from analogous subsurface reservoirs.     

Tight oil play characterisation: the lower–middle Permian Lucaogou Formation in the Jimusar Sag,Junggar Basin,Northwest China

The lower–middle Permian Lucaogou (P₂l) Formation is a “sandwich-type’’ combination of source rocks and reservoirs that is considered to be a potential tight oil reservoir in the Jimusar Sag (JS). We investigated the P₂l Formation using a designated workflow to assess its potential as a viable tight oil reservoir play using geological, petrographical, petrophysical, and geochemical characterisation of core samples. The results showed that the P₂l source rocks have a widespread distribution (up to 1500 km²), a huge thickness (up to 160 m), a relatively high abundance of organic matter (averaging 3.12 wt%), a good sapropelic quality, and a moderate thermal maturity. The reservoir consists mainly of dolomites and siltstones, predominantly characterised by secondary dissolved pores, with medium–high porosity (averaging 9.1%) and relative low permeability (averaging 0.26 mD), high abundance of brittle minerals (averaging 87.1%), and low abundance of clay minerals (averaging 11.2%) with low water sensitivity. The results demonstrate that in the JS area the P₂l Formation has great potential for tight oil production with its considerable hydrocarbon expulsion quantities, good oil storage capability, and reservoir frackability potential and provide a basis for further evaluation of the tight oil potential of the P₂l Formation in the wider Junggar Basin and for identifying similar plays elsewhere.     

黄骅坳陷歧口凹陷沙河街组二段物源分析

为弄清歧口凹陷沙二段物源-沉积体系展布特征,通过碎屑组分、重矿物、稀土元素等多参数物源分析方法,对歧口凹陷周边源区分布及其各自对凹陷内部沉积的影响范围进行系统研究。发现各源区母岩岩石类型以中基性喷出岩为主。研究区存在北部、西部和南部3大物源区,可细分为北部燕山、西北沧县隆起、西部港西和港东凸起以及南部赵北和张东6个分支物源。其中北部燕山和西北沧县隆起分支物源控制了北大港潜山北部以及板桥凹陷一带的大部分三角洲沉积,并与西部港西凸起分支物源在港中一带形成混源滩坝沉积。而港西、港东、赵北和张东4分支物源仅控制其周边的扇三角洲和滩坝相沉积。总之,古物源区与沉积体系具有良好的空间配置关系,为沙二段岩性地层油气藏的形成提供了良好的物质基础。     

渤海海域郯庐断裂带新生代活动方式与演化规律——以青东凹陷为例

青东凹陷东边界为郯庐断裂带在渤海海域内西支断裂所在,平面上由4条北北东向断裂呈左阶雁列式排列,剖面上以上盘下降为主,局部具有张扭性和压扭性花状构造现象。青东凹陷东界上的郯庐断裂新生代经历了古近纪右行平移正断层活动、古近纪末盆地挤压反转中的逆右行平移、新近纪的弱拉张活动和第四纪以来的逆右行平移4个演化阶段。古近纪断陷期,先存的郯庐断裂带由于具有较低的强度,在南北向伸展应力场作用下复活并表现为具有右行平移分量的斜向拉张活动,在浅部新生4条左阶雁列式断层,并与盆地内北西向基底断裂系统和东西向新生正断层共同控制了古近系的沉积格局。古近纪末发生了盆地反转,结束了断陷盆地发育阶段,在北东东-南西西向区域挤压应力作用下郯庐断裂表现为逆右行平移活动。新近纪坳陷阶段,盆地内构造活动较弱,主要受控于岩石圈热沉降作用,但郯庐断裂仍具有较弱的伸展活动。第四纪以来,郯庐断裂再次转变为逆右行平移活动。     

基于岩性相单元和孔隙结构的低孔低渗储层有效性测井识别方法:以西湖凹陷NB1构造为例

东海西湖凹陷是近海最大的盆地之一,近些年在中深层花港组储层中获得重大发现.然而,由于储层具有厚度大、非均质性强、低孔低渗、孔隙结构复杂等特征,给精细评价和甜点储层的预测带来极大困难.利用高分辨率电成像资料,在岩性和层理构造识别的基础上,将研究区储层划分成槽状交错层理细中砂岩、板状交错层理细中砂岩、槽状交错层理细砂岩、板...     

文南油田沙一下亚段沉积微相及其与油气的关系

文南油田位于河南东濮凹陷中央隆起带向南的倾伏端,紧邻前梨园生油洼陷。研究区构造面积约55km2,是极为有利的油气聚集带。古近系沙河街组一段下亚段(Es1x)是该油田开发中的一个主要接替层系,油藏类型属于岩性、断层岩性和断块型油藏,油气聚集受砂体展布和断裂输导系统的控制。砂体展布受物源区性质和古沉积环境制约,因此,沉积微相与油气分布有密切关系。储集层主要发育在前梨园—席城集以西、胡状集—庆祖集以东地区,属于三角洲前缘水下分流河道、河口坝及前缘席状砂沉积。水下分流河道及河口坝砂层较厚,约4—7m,研究区分布广泛。研究区还存在分布广泛而稳定水下分流河道侧缘、河口坝侧缘以及席状砂砂体,砂层较薄,厚约2—3m。在水下分流河道的主河道沉积中,微相油层的层数多、厚度大,因此当其与构造高点得到合理配置时,常形成高产油流聚集区。     

歧口凹陷沙三段成岩作用对储层物性贡献率研究

为定量描述各种成岩作用对储层物性变化的影响,提出成岩综合系数(C),该系数由压实作用(α)、胶结作用(β)、溶蚀作用(γ)等3个成岩要素贡献率之和构成。通过对研究区大量岩芯薄片分析统计,经多元回归,建立各种成岩作用与孔隙度之间的关系式,得出它们对储层物性的贡献率,认为胶结作用是储层物性的主控因素。