大庆长垣以东朝长—双城地区扶余油层沉积微相特征

Characteristics of sedimentary microfacies of Fuyu reservoir in Chaochang-Shuangcheng area,eastern Daqing placanticline

在岩芯观察描述的基础上,依据岩石学特征、沉积构造、生物化石及测井曲线响应特征等标志,对大庆长垣以东朝长—双城地区扶余油层沉积相类型及特征进行了分析,结果表明区内扶余油层(Kf)发育浅水三角洲相和曲流河相两种沉积相类型,进一步可以划分为5种亚相和11种微相,主要砂体类型为河床边滩沉积、三角洲平原分流河道砂体和三角洲前缘水下分流河道砂体。在此基础上结合高分辨率层序地层划分,将扶余油层划分为2个长期基准面旋回和7个中期基准面旋回。编制了层序地层格架内研究区沉积微相平面展布图,并分析了其平面展布和垂向演化规律。研究表明,垂向上沉积水体表现为由深逐渐变浅再变深的过程,在MSC4下降半旋回至MSC5上升半旋回沉积时期,达到最浅。该时期全区范围内发育河床亚相和三角洲平原亚相,河道砂体规模最大,为储集砂体发育的最佳时期。

Based on core observation and description,combined with various marks,such as rock types,sedimentary structure,fossils and characteristics of logging curve response,the authors analyzed depositional facies and characteristics of Fuyu reservoir（ Kf） in Chaochang-Shuangcheng area,eastern Daqing placanticline. The results show that two types of facies,shallow-water delta and meandering river sedimentary facies are developed in the studied area. They are further divided into five subphases and eleven microphases. Types of sand bodies mainly include bed-side beach deposition,delta plain distributary channel sand body,as well as delta front underwater distributary channel sand body. On this basis,combined with high-resolution sequence stratigraphic division,Fuyu reservoir can be divided into two long-term cyclic sequences,seven middle-term cyclic sequences. Sedimentary microfacies plane distribution maps are established according to analysis results and the regulations on the planedistribution and vertical evolution are analyzed. Vertically,changes of depth of water show such procedure： it starts from deep to shallow,and then gradually varies from shallow to deep. In turning point of MSC4 drop-half cycle to MSC5 rise-half cycle,the depth of water reaches the shallowest value. Results show that the shallow-water delta sedimentary facies are developed in the studied area and types of sand bodies are mainly delta plain. In this period,river and delta plain are developed in the whole area,channel sand body is in max thickness,and it is the best time for the development of sand body as reservoir.