白25井区上乌尔禾组沉积相研究

Study on sedimentary facies of Upper Wuerhe Formation in Bai 25 block

沉积相研究对控制储集砂体的空间展布有重要意义。为了对白25井区的沉积相类型进行有效的研究,在前人关于白25井区沉积相研究的基础上,结合白25井区的岩心资料、测录井资料,分析化验数据等相关资料后,认为白25井区上乌尔禾组发育的主要岩石相类型有:下部主要是红褐色、红色砂砾岩,发育块状构造;中部发育灰色、灰绿色砂砾岩,可见一定的粒序性,发育平行层理或交错层理。上部发育灰色、灰绿色砂岩以及泥岩,泥岩中可见水平层理。自下而上沉积物粒度逐渐变细,在垂向上反映了一个砂体不断向岸退积的沉积序列。白25井区上乌尔禾组发育的沉积相类型为扇三角洲,而不是冲积扇,可以识别出扇三角洲平原,扇三角洲前缘,前扇三角洲三个亚相以及扇面河道,水下分流河道等9个微相。

The study of sedimentary facies was of great importance in studying the distribution of the sandy reservoir.Aiming at studying the sedimentary facies type of Upper Wuerhe Formation of Bai 25 block,based on the observation of cores,and well logging,mud logging,analytical experiment data,it was believed that Upper Wuerhe Formation of Bai 25 block developed,a set of red and brown sand stone and glutenite sediment in the bottle,developing massive structure,grayish-green glutenite in the middle of the formation with Parallel bedding or cross beding,grayish-green mud stone on the top.From bottle to top,the granularity of the rock decreased,reflecting a sedimentary sequence of retrogradation.And Upper Wuerhe Formation of Bai 25 block developed a sedimentary facies of fan delta,in stead of fan.The sedimentary facies can be divided into 3 subfacies of fan-delta front and frontal delta and plain delta and 9 corresponding micro-facies,including stream channel and underwater distributary channel and so on.