【作者】 袁红旗；

【导师】 吕延防； 朱筱敏；

【作者基本信息】 大庆石油学院 ， 矿产普查与勘探， 2008， 博士

【摘要】 以高分辨层序地层学理论、储层定量描述理论为指导,综合利用岩芯资料、测井资料和地震资料以及室内化验分析资料,以计算机为手段,对宋芳屯地区葡萄花油层进行层序地层学及砂体展布定量研究。首先在总结多种地层划分对比方法的基础上,充分借鉴前人研究成果,确定适用于研究区自身地质特点的层序划分对比方法。然后,进行跨区域过油田最密井网区主干大剖面的高分辨率层序地层划分对比工作,了解宋芳屯地区葡萄花油层地层发育特点及总体沉积特征,为全区高分辨层序地层划分对比打下坚实基础。进而以多条贯穿研究区的南北向和东西向骨架剖面的精细层序地层划分对比为依托,建立宋芳屯油田葡萄花油层的高分辨率层序地层格架,同时通过对跨大庆长垣与宋芳屯地区密集骨架大剖面的精细层序地层划分对比工作,建立了宋芳屯地区葡萄花油层与大庆长垣对于地层的联系。在等时精细地层格架的基础上,通过对邻区杏13高密度井网区的精细解剖得到葡萄花油层砂体发育的一系列几何参数及展布特征,指导宋芳屯油田低密度井网区葡萄花油层砂体定量及砂体展布特征的研究工作。研究区目的层对应于长垣白垩系葡萄花油层的PI1～PI3砂层组,可以划分为一个长期基准面半旋回、2个中期基准面旋回和12个短期基准面旋回。对研究区可能存在的4种地层模式分别加以论证,最终确定顺源逐层上超为宋芳屯地区葡萄花油层的地层沉积模式。详细研究了地层展布特征,北厚南薄,下部的3个短期基准面旋回p1900、p1800、p1700依次向南尖灭减薄。在层序格架内,对密集井网区进行单砂体成因解剖,进行沉积微相研究,确定研究区为河控浅水三角洲沉积。其具有建设性三角洲沉积特征,岩性主要以细砂岩、粉砂岩、泥质粉砂岩及薄层泥岩为主,岩性较粗,粒度概率曲线多为反映牵引流沉积的两段式。沉积构造上冲刷界面极为发育,水道多且规模小,反映深水沉积或海相的古生物化石少见。单井大多数下部为进积准层序组,上部为退积准层序组,具有典型的两端对称的“菱形”垂向沉积序列。三角洲的三层结构不发育,三角洲相带分异明显,各亚相带发育齐备,且三角洲前缘亚相带十分宽广。砂体一般顺物源分布,具有明显的方向性,并且河口坝砂体不发育。研究区主要微相类型为河控浅水三角洲分流平原亚相的分流河道、道间砂、道间泥微相;内前缘亚相的水下分流河道、水下道间砂、水下道间泥微相;外前缘亚相的残留水下分流河道、席状砂、远砂坝微相和前三角洲泥微相。沉积微相及其垂向演化受控于地层基准面变化。葡萄花油层沉积早期,地层基准面下降,沉积相向湖中央迁移,自下而上依次形成前三角洲、外前缘、内前缘、分流平原,构成水体向上变浅的沉积序列;葡萄花油层沉积晚期,地层基准面上升,沉积相向陆迁移,自下而上依次形成分流平原、内前缘、外前缘,构成水体向上变深的沉积序列。采用类别方法和储层定量描述技术开展砂体展布定量研究。首先确定定量研究的对象为分流河道砂、废弃河道砂、道间砂、水下分流河道砂、水下道间砂、残留水下分流河道、席状砂、远砂坝内坝砂、中坝砂和外坝砂。然后确定定量研究的指标,最终选择了砂体平均厚度、厚度标准差、厚度偏度、厚度峰度、砂体宽度、宽厚比、砂体长度、长厚比、河道分叉范围角α、河道分叉范围法线角β共10个定量研究指标。各类砂体其定量研究指标有着各自的特点,定量反映出各种不同类型砂体各自的沉积特征及分布特点。研究表明,宋芳屯地区葡萄花油层河道砂体自北向南分叉延伸,其中分流河道砂体厚度最大(平均值为4.07m),砂体厚度离散程度最大,厚度频率曲线十分平缓;平面上分流河道砂体在河道砂体中也最宽(158m～986m),延伸很远(延伸长度大于1500m),宽厚比与长厚比也比较大;废弃河道砂体厚度居中(平均值为2.89m),厚度标准差较大,厚度频率直方图上各厚度区间所占频率差异较大,呈连续变化形态,表明废弃河道砂体厚度变化较为剧烈,主要由突然废弃和逐渐废弃两种不同的废弃方式造成;平面上废弃河道砂体呈弯曲状,规模较小(83m～144m),延伸长度较短(139m～690m),砂体大多成弯曲状分布,连续性较差;水下分流河道砂体同前两种河道砂体比较砂体厚度较小(平均值为2.28),厚度标准差也较小,为1.26,表明砂体厚度离散程度较小,砂体厚度较为集中;平面上水下分流河道砂体规模也很大,宽度分布范围较广(70m～537m),既有较为宽阔的砂体,也有比较窄小的砂体,延伸长度也较远(466m～1683m)。统计表明,宋芳屯油田葡萄花油层分流河道方位角范围角α为117°,河道分叉法线角β为30°,类似现代沉积,表明次一级分流河道大致分布在主干河道的两侧,偏离不大,砂体主要受河流控制,波浪和沿岸流作用较小。道间砂和水下分流河道道间砂平均厚度、厚度标准差、厚度偏度、厚度峰度都相差不大;但二者的平面分布有所差异,道间砂宽度范围与延伸长度范围同水下分流河道道间砂相比都要小,表明尽管同样是河道之间的砂体沉积,但是前者河水严格受河道限制,而后者河道限制大大减弱,因此,水下分流河道道间砂的发育程度要比分流河道道间砂的发育程度要好,延伸要远,范围更大。更多还原

【Abstract】 The quantitative study of sequence stratigraphy and distribution of sandbody has been done on Putaohua reservoir in Songfangtun area, using the data of core, laboratory analysis, well logging and seismic, realized by computer, under the direction of high resolution sequence stratigraphy theory and reservoir quantitative description theory. After comparing the advantages and disadvantages among different methods of stratigraphic classification and correlation, the method available to the study area is found on the base of the former researches by others. And then the high resolution sequence stratigraphic classification and correlation of bone sections is started, which are interregional and cross the densest well network, and the knowledge of the characteristics of strata and the general deposition of Putaohua reservoir in Songfangtun area applies strong bases for this work.The plan for stratigraphic classification, which is suitable for the study area, has been established, after summing up the former achievements by others about the classification of Cretaceous in Songliao basin. On this base, the high resolution formation skeleton of Putaohua reservoir in Songfangtun area is built up, dependent on the stratigraphic classification of several north-south and east-west bone sectons through the whole area. moreover, the relationship between Putaohua reservoir in Songfangtun area and the one of placanticline in Daqing oilfield has been founded through the classification and correlation of bone sections in both areas.The target stratum of the study area are equivalent to PI1～PI3 of Putaohua reservoir of placanticline, and it can be divided into one symmetric long-basal level-hemicycle, two medium-basal level-cycles, and twelve short-basal level-cycles. And four potential stratigraphic models are discussed separately, and then the stratigraphic model is found that the strata were onlap zone by zone with the source. Through the detailed study, it is concluded that the horizones in the north were thick, while the ones in the south were thin, and that the strata of the lower three short-basal level-cycles p1900, p1800 and p1700 ordinally became thinner, and ultimately died out southtowards.This paper does genetic anatomy to single sandbody in the densest well network beside the formation skeleton, and analyses the microfacies. It confirms that it was fluvial dominated shallow delta, and then generalized its characteristics. The main microfacies are distributary channel, intrachannel sand and intrachannel mud microfacies in delta plain subfacies; and underwater distributary channel, underwater intrachannel sand and underwater intrachannel mud microfacies in inner front subfacies; and relic underwater distributary channel, sand sheet and distal bar microfacies in outer front subfacies; and prodelta mud microfacies, and so on. The vertical evolution suggested the control of basal-level to microfacies: the basal-level descent in the early stage of Putaohua Formation, and sediments migrated towards lake, and formed a shallowing-upward sequence that it was prodelta, outer front, inner front and delta plain ordinally from bottom to top; while in the late period, the basal-level ascent, and sediments migrated towards land, which formed a deeping-upward sequence that it was delta plain, inner front and outer front ordinally from bottom to top.Lastly, this paper studies the distribution of sandbody quantitatively. Firstly, it defines the objects, such as the sandbody of distributary channel, abandoned channel, intrachannel, underwater distributary channel, underwater intrachannel, relic underwater distributary channel, sand sheet, and the inner, middle and outer of distal bar. Secondly, it gets the index for quantitative study, and selects ten parameters such as average value, standard difference, bias angle, peakedness of sandbody thickness, width, width to-thickness ratio, length, length to-thickness ratio, channel offset amplitude angleα, and channel offset amplitude normal angleβ, and so on. Different index has different characteristics and they can reflect the individual sedimentary characteristics and the distribution of sandbody of different type.更多还原