【作者】 李延平；

【导师】 林振宏； 陈树民；

【作者基本信息】 中国海洋大学 ， 海洋地质， 2007， 博士

【摘要】 大庆长垣及周边地区扶杨油层是近期提交储量的首选地区,扶杨油层属于松辽盆地大型坳陷阶段沉积形成的下部旋回,以浅水湖泊-三角洲沉积体系为主。该区存在的主要问题是受多物源控制形成的错叠连片分流河道砂体,主要呈条带状,河道规模小,砂体薄,物性差,产能低;地层岩性横向变化快,开发效果差;地层埋深深,后期成岩作用强,波阻抗差异小,地震反射特征不明显;河道砂体岩性圈闭发育,主要形成岩性、断层-岩性油气藏。勘探的主要目标是要预测渗透性储层,寻找主河道和识别有利于成藏的主体河道砂体。由于扶杨油层特定的地质沉积条件,给识别河道砂体带来很大的难题。为此,开展扶杨油层河道砂体地质-地震识别技术联合攻关,以州201开发区块为试验区,在密集井网控制下深入解剖扶杨油层高分辨率层序地层格架特征和沉积微相时空演化,搞清河道砂体类型、几何形态和空间展布规律,为扶杨油层河道砂体地震识别提供精确的地质模式,形成有效、实用的扶杨油层河道砂体识别方法与技术,指导勘探部署。本文综合采用层序地层学、高分辨率层序地层学、沉积学、地震地层学、石油地质学等多学科理论和方法,从研究沉积微相及小层准层序的划分、对比入手,重点研究泉四段扶余油层地层沉积特征、层序特征、沉积相带展布、纵横向变化规律,建立了精细地层格架,阐明了扶余油层小层沉积相演化规律,为扶杨油层河道砂体地震识别提供精确的地质模式。综合研究认为该区扶杨油层发育浅水湖泊三角洲相和浅水湖泊相,主要河道类型有近端和远端曲流型分流河道、近端和远端低弯型网状分流河道、近端和远端顺直型分流河道及水下分流河道。分流河道砂储层类型较为发育,河道砂体厚度薄、粒度细,河道宽一般150～500m左右。扶余油层浅水湖泊存在向上变深的准层序,是河湖共同作用的结果,湖水覆淹,造成溺谷,形成远端分流河道。泉四段扶余油层是一个三级气候层序,泉四段与泉三段地层分界是其层序的底界;T2反射层也是(Ⅱ型)层序边界,是泉四段层序的顶界。该层序发育水进体系域和顶部薄层强制水退边缘体系域,水进体系域早期发育近端和远端曲流河沉积,晚期发育远端低弯型网状河和顺直河沉积。泉四段扶余油层沉积微相以泛滥平原泥、滨湖泥、浅湖泥最为发育。这些泥相常常包裹或覆盖水上、水下分流河道砂体以及天然堤、决口扇、河口坝、薄层砂砂体,可形成良好的储盖组合,有利于形成岩性圈闭油气藏。认清沉积相的演化特点、层序发育规律及砂体微相的展布特征,对于地震河道砂体识别、储层预测、储量估算、寻找岩性油气藏等都具有重要的指导意义。更多还原

【Abstract】 Daqing placanticline and around areas of Fuyang oil-bearing layer is the first region where will provide reserves in recently, Fuyang oil-bearing layer belongs to low depositional cycle of large depression stage in Songliao basin, its depositional environment belongs to shallow lacustrine-delta system mainly. The major problem in this areas is that the geological condition is complicated. Distributary channel sand bodies is controlled by poly-provenience, it interchanges in vertical and horizontal, takes on strip, has small scale, thin thickness, bad physical properties and low produce. Stratigraphic lithologic composition change frequently in transverse direction, caused poor development effects. The strata is deep in subterranean, strong in diagenesis and littlie difference in wave impedance, its seismic reflect feature is not clear. Lithologic trap of sand bodies is common, form lithologic and fault-lithologic oil-gas pool mainly.The main exploration target is predicting permeable reservoirs, looking for and identifying channel sand bodies that is favorable to forming oil-gas pool. Owing to Fuyang oil-bearing layer special geological condition, it is rather difficulty to identify channel sand bodies.Therefore it is necessary for us to develop technology of identifying channel sand bodies of Fuyang oil-bearing layer with geology and seism together to tackle key problem. The Zhou 201 site is chose as experiment areas, under control of dense well array, which will be studied deeply from high resolution sequence formwork to sedimentary facies time-space evolutionary rule of Fuyang oil-bearing layer. Making clear types of sand body, shape of its geometry and characteristics of its distribution in space, will provide a precise geological model for Fuyang oil-bearing layer channel sand bodies seismic identifying, form a effective and utility Fuyang oil-bearing layer channel sand bodies identifying methods and technology to guide exploration deployment.Various kinds of comprehensive theories and methods is applied in this paper, such as sequence, high resolution sequence, sedimentology, seismic stratigraphy, petroleum geology. Beginning with study of sedimentary microfacis, parasequence stratigraphic division and correlation, Fuyu oil-bearing layer sedimentary characteristics, sequence formwork, sedimentary facies belts rules of distribution in vertical and horizontal have been mainly studied. Through the above study, stratigraphic subtle formwork has been established, sedimentary facies evolutional rules have been known, that provided a precise geological model for Fuyang oil-bearing layer channel sand bodies seismic identifying.Through this comprehensive study, it has been determined that Fuyang oil-bearing layer belongs to shallow lacustrine-delta facies and shallow lacustrine facies, the main kinds of channel include proximal and distal meandering distributary channel, proximal and distal low-sinuosity distributary channel , proximal and distal straight distributary channel and subaqueous distributary channel. The distributary channel sand developed most, and it is favorable reservoir. The hannel sand body is thin in thickness, fine in grain. The channel width is 150～500m. Upward water deepen parasequence is existent in Fuyu oil-bearing layer shallow lake, it is result of river and lake working together, flooding and submerging of lake water cause drowned valley, form distal distributary channel .Quan4 member Fuyu oil-bearing layer is a third-grade climate sequence, the boundary between Quan4 member and Quan3 member is sequence boundary below, T2 reflect layer is sequence boundary above. This sequence include both trangressive systems tract (TST) down and forced regressive margin systems tract (FRMST). TST develop distal and proximal meandering river deposit early, and distal and proximal low-sinuosity river deposit late.The muddy rock microfacies in Quan4 member Fuyu oil-bearing layer is large development, and often contain sand that belong to overwater and subaqueous distributary channel, natural levee, crevasse as well as mouth bar. Consequently, form good reservoir and seal assemblage, which is favorable for the formation of lithologic trap hydrocarbon reservoir.Clear understanding of the evolution features of sedimentary facies, law of sequence evolutioin and distribution rules of sand body microfacies is meaningful to channel sand body seismic identifying, reservoir prediction, reserve estimation and lithologic trap oil-gas pool discovery.更多还原