塔河东部三叠系阿四段水下分流河道内部结构及夹层分布特征

由于油藏开发处于中期阶段,地层能量严重衰竭,为了达到更好的注水效果,利用录井、测井和取心等资料,以三叠系阿四段水下分流河道内部结构的研究为基本出发点,识别和划分有效夹层,进而对夹层分布特征进行研究。结果表明:三叠系阿四段河道砂体岩性为一套浅灰色、灰绿色中–细粒砂岩,砂体内部由前积体和前积层构成,叠加样式为前积层的垂向、侧向加积型和进积型的复合式叠加,前积体的进积型叠加;夹层的分布与河道的形态及所处的位置相关,不同类型的夹层因发育形态和位置不同,分布具有规律性;有效夹层在纵向上发育1–2套,平面上呈不规则长片状分布,向边部减薄,空间上夹层产状近水平展布。研究结果客观地反映了水下分流河道砂内部的三维结构特征,为油藏的注水开发提供可靠的资料和依据。

Internal structure and interlayer distribution characteristics of underwater distributary channel in the fourth member of Triassic Akekule formation in the eastern Tahe oilfield

Due to the serious depletion of formation energy in in the middle stage of reservoir development, in order to achieve better water injection effect, logging, coring and other data are used to identify and divide effective interlayers based on the study of internal structure of underwater distributary channel of the fourth member of Triassic Akekule formation, and then to carry out research on the distribution characteristics of interlayers. The results show that the lithology of the channel sand body of the fourth member of the Triassic system is a set of light gray, gray green medium fine grained sandstone, and the internal structure of the channel is composed of the foreset bodies and foresets. The superimposition style is the compound type with vertical and lateral accretion type of the foresets and progradation type, and the progradation type of the foreset bodies. The interlayer distribution is related to the shape and location of the channel. Different types of interlayer have regular distribution due to different development morphology and location. There are 1-2 sets of effective interlayers in the longitudinal direction, which are distributed irregularly in the plane and thinned to the edge, and the occurrence of intercalation is nearly horizontal in spatially. The research results objectively reflect the 3 D structure characteristics of underwater distributary channel sand, and provide reliable data and basis for water injection development of reservoirs.