东海陆架盆地西湖凹陷渐新统花港组年代标尺及层序界面定量识别

西湖凹陷是东海陆架盆地中重要的含油气凹陷,近期勘探证实渐新统花港组是当前主力产气层段;截至目前,西湖凹陷花港组层序地层划分方案还存在较大争议,严重制约了砂体等时对比及油气精细勘探进程。依据层序地层学结合天文旋回理论,利用小波变换和INPEFA技术对自然伽马曲线进行数学分析得到小波信号曲线、频谱及INPEFA曲线,建立了西湖凹陷花港组年代标尺及高精度层序界面格架。通过小波变换将GR曲线重构成不同阶次的小波信号曲线和频谱,以异常振动和能量团变化趋势凸显层序界面和旋回信息;同时,利用最大熵谱分析技术对GR曲线进行积分处理获得INPEFA曲线,以拐点和正负趋势定量拾取层序界面和旋回特征,将花港组划分为5套三级层序（自下而上分别命名为SQ₁—SQ₅）。利用频谱分析明确三级层序内部地层叠置旋回,结合小波信号曲线变化特征,可将花港组划分为12套四级层序（自下而上分别命名为H₁₂—H₁）。花港组GR曲线的多窗口频谱分析结果表明,5套三级层序发育持续时间介于1 ~ 3 Myr。通过多尺度多方法融合测井技术对缺少岩心和古生物化石区构建多级次等时层序地层格架具有一定推广意义,为渐新统花港组后期勘探开发提供一定的技术支持。     

琼东南盆地南部隆起带渐新统崖城组层序沉积模式

近期在琼东南盆地南部隆起带前古近系潜山基岩储层和渐新统崖城组砂岩储层中连续获得了天然气勘探重大突破。为了进一步明确崖城组沉积物源及沉积相带展布、为该区天然气勘探部署提供技术支撑,基于最新的钻井资料,结合地震资料解释成果,研究了该盆地南部隆起带崖城组层序地层、沉积物源及层序格架下的沉积相展布。研究结果表明：①南部隆起带崖城组发育3个三级层序,每个三级层序受三级海平面变化控制周期性发育海侵体系域和高位体系域,低位体系域以对老层序高位体系域的改造为主;②崖城组具有多沉积中心与多物源的特点,各凹陷缓坡发育宽相带的扇三角洲—陆棚沉积体系,陡坡发育窄相带的水下扇—陆棚沉积体系;③南部隆起崖城组发育海侵体系域、高位体系域和低位体系域3种层序沉积模式;④南部隆起带前古近系潜山花岗岩基底遭受了长期暴露剥蚀,古隆起形成了重要的潜山型花岗岩储层,崖城组残留了较大面积的扇三角洲砂体,低位期暴露剥蚀改造,形成了具一定规模的砂岩储层。结论认为,该研究成果可以为该区崖城组碎屑岩储层分布规律研究提供依据。     

THE OLIGOCENE–MIOCENE MENILITE FORMATION IN THE UKRAINIAN CARPATHIANS: A WORLD‐CLASS SOURCE ROCK

This study investigates the hydrocarbon potential of Oligocene–Miocene shales in the Menilite Formation, the main source rock in the Ukrainian Carpathians. The study is based on the analysis of 233 samples collected from outcrops along the Chechva River in western Ukraine in order to analyse bulk parameters (TOC, Rock‐Eval), biomarkers and maceral composition. In Ukraine, the Menilite Formation is conventionally divided into Lower (Lower Oligocene), Middle (Upper Oligocene) and Upper (Lower Miocene) Members. The Early Oligocene and Early Miocene ages of the lower and upper members are confirmed by new nannoplankton data. The Lower Menilite Member is approximately 330 m thick in the study area and contains numerous chert beds and turbidite sandstones in its lower part together with organic‐rich black shales. The shales have a high content of silica which was probably derived from siliceous micro‐organisms. The TOC content of the shales frequently exceeds 20 wt.% and averages 9.76 wt.%. HI values range between 600 and 300 mgHC/gTOC (max. 800 mgHC/gTOC). The Middle Member contains thin black shale intervals but was not studied in detail. The Upper Member is about 1300 m thick in the study area and is composed mainly of organic‐rich shales. Chert layers are present near the base of the Member, and a prominent tuff horizon in the upper part represents a volcanic phase during shale deposition. The member grades into overlying molasse sediments. The average TOC content of the Upper Menilite succession is 5.17 wt.% but exceeds 20 wt.% near its base. Low T_max and vitrinite reflectance measurements for the Lower (419°C and 0.24–0.34 %R_r, respectively) and Upper (425°C and 0.26–0.32 %R_r, respectively) Menilite Member successions indicate thermal immaturity. Biomarker and maceral data suggest a dominantly marine (Type II) organic matter input mixed with varying amounts of land‐plant derived material, and indicate varying redox and salinity conditions during deposition. Determination of the Source Potential Index (SPI) shows that the Menilite Formation in the study area has the potential to generate up to 74.5 tons of hydrocarbons per m². The Chechva River outcrops therefore appear to have a significantly higher generation potential than other source rocks in the Paratethys realm. These very high SPI values for the Menilite Formation may explain why a relatively small area in Ukraine hosts about 70% of the known hydrocarbon reserves in the northern and eastern Carpathian fold‐thrust belt.     

FACIES HETEROGENEITIES AND 3D POROSITY MODELLING IN AN OLIGOCENE (UPPER CHATTIAN) CARBONATE RAMP,SALENTO PENINSULA,SOUTHERN ITALY

Appraisal of the volumes of fluid in a carbonate reservoir will typically require a reliable predictive model. This can be achieved by combining studies of well-exposed carbonate successions with 3D models in order to obtain reliable quantitative data. In this paper, we present a detailed outcrop study and a 3D porosity model of a well-exposed Oligocene carbonate ramp (Salento Peninsula, southern Italy) to investigate the nature of small-scale facies and porosity heterogeneities. Porosity and permeability in the ramp carbonates appear to be controlled by the original mineralogy of skeletal components and by depositional textures. The aims of the study were therefore to identify the factors controlling porosity development in an undeformed carbonate ramp; to model the scale-dependent heterogeneities characteristic of the facies associations; and finally to produce a 3D model of the porosity distribution. The upper Chattian Porto Badisco Calcarenite which crops out along the coast of the Salento Peninsula consists of six lithofacies ranging from inner ramp deposits to fine-grained outer ramp calcarenites. The lithofacies are: inner ramp small benthic foraminiferal wackestone-packstones associated with (i) sea grass meadows (SG) and (ii) coral mounds (CM) consisting of coral bioconstructions with a floatstone/packstone matrix; middle ramp (iii) large rotaliid packstones to wackestone-packstones (LR), (iv) rhodolith floatstone-rudstones (RF), and (v) large lepidocyclinid packstones (LL); and (vi) outer ramp fine-grained bioclastic calcarenites (FC). A total of 38 samples collected from six stratigraphic sections (A, B, D, J, E, LO), measured in the Porto Badisco ravine, were investigated to discriminate the types of porosity. Effective and total porosity was measured using a helium pycnometer. The 3D porosity modelling was performed using PETREL™ 2016 software (Schlumberger). Four main types of porosity were recognized in the carbonates: interparticle, intraparticle, vuggy and mouldic. Primary porosity (inter- and intraparticle) is limited to middle ramp lithofacies (LL and LR) and outer ramp lithofacies (FC), whereas secondary porosity (vuggy and mouldic) was present in both inner ramp lithofacies (CM and SG) and middle ramp red algal lithofacies (RF). In the Porto Badisco carbonates, stratigraphic complexity and the distribution of primary porosity are controlled by lateral and vertical variations in depositional facies. Significant secondary porosity was produced by the dissolution of aragonitic and high-magnesium calcite components, which are dominant in the sea-grass and coral mound facies of the inner ramp and in the rhodolith floatstone-rudstones of the middle ramp. 3D models were developed for both effective and total porosity distribution. The porosity models show a clear correlation with facies heterogeneities. However of the two models, the effective porosity model shows the best correlation with the 3D facies model, and shows a general increase in effective porosity basinwards in the middle ramp facies.     

柴达木盆地英西地区渐新统下干柴沟组上段储层微观孔隙结构特征

柴达木盆地英西地区渐新统下干柴沟组上段为“自生自储”型油气藏。利用X射线衍射全岩矿物含量分析、薄片鉴定、扫描电镜观察、二氧化碳吸附、氮气吸附/脱附、高压压汞、核磁共振、自发渗吸等实验手段,系统分析柴达木盆地英西地区渐新统下干柴沟组上段储层特征,精细表征了其微观孔隙结构特征。研究结果表明：(1)英西地区渐新统下干柴沟组上段储层为细粒沉积岩,其矿物成分主要为白云石和铁白云石等碳酸盐,含有长石、石英等陆源碎屑,伊蒙混层和伊利石等黏土矿物。(2)研究区储集岩整体较为致密,孔隙度为1.0%～14.5%,平均为4.0%,渗透率为0.011～6.146 mD,平均为0.125 mD,具有低孔特低渗特征。(3)研究区储集岩的孔隙类型以晶间孔、溶蚀孔、溶洞和裂缝为主,储层孔隙形态为平行狭缝型。(4)研究区微孔的质量体积平均为0.005 6 mL/g,占总孔的质量体积的34.70%;中孔的质量体积平均为0.006 6 mL/g,占总孔体积的40.84%,宏孔的质量体积相对较小,为0.003 9 mL/g,占总孔体积的24.46%,因此,对岩石储集性贡献最大的为中孔,其次是微孔。     

Cr3+聚合物弱凝胶调驱剖面变化规律及改善方法

采用分子内交联为主的Cr³⁺聚合物弱凝胶,通过“分注分采”岩心驱替实验研究调驱剂段塞尺寸、岩石渗透率和原油黏度对储层吸液剖面和产液剖面的影响。针对渤海油田LD10-1区块渐新统东营组进行了“堵/调/驱”实验。研究结果表明：①调驱剂段塞尺寸对注采两端液流转向和剖面返转时机没有影响,但超过0.3 PV后单位体积段塞尺寸Cr³⁺聚合物弱凝胶提高原油采收率增幅减小,随储层渗透率级差和原油黏度增大,注采两端液流转向时机延后,剖面返转时机提前;②“有机/无机”复合凝胶体系封堵高渗透率层、聚合物微球调控微观非均质性和稠油流度改善剂提高驱油效率等3种措施同时实施,可提高聚合物弱凝胶调驱后的采收率;③“堵/调/驱”组合提高采收率机理为：封堵优势渗流通道扩大非均质储层宏观波及体积、聚合物微球在变径孔隙或喉道处发生桥堵实现微观液流转向、高效驱油剂可进入未波及孔喉区域发挥降黏原油、降低油水界面张力和高效驱替等3种作用。     

利用镜质体反射率计算泥岩排替压力

本文在大量实验数据的基础上，建立了泥岩排替压力与镜质体反射率之间的函数关系。并以汤原断陷主要油气盖层———始新统—渐新统泥岩为例，利用镜质体反射率研究了其排替压力在平面上的变化规律。     

Palynological evidence sheds new light on the age of the Liuqu Conglomerates in Tibet and its geological significance

The Liuqu Conglomerates consist of a suit of terrestrial molasse deposits formed in a foreland basin of the Himalaya-Tibet orogenic belt before the collision of India and Eurasia.These deposits record considerable geological information regarding the late tectonic evolution of the Neotethyan ocean.The palynological study of interlayers of mudstone and mud-sandstones indicates an Oligocene age.The palynological assemblage consists mainly of deciduous broad-leaved angiosperms,with some coniferous gymnosperms ...