玛湖凹陷夏子街斜坡坡折带发育特征及控砂作用

Characteristics of Xiazijie Slope Breaks in Mahu Sag and Control Effect on Sand Bodies

准噶尔盆地玛湖凹陷夏子街斜坡发育多级坡折带。以三维地震资料为主,结合测井、录井及野外踏勘资料,对坡折带发育特征展开深入研究。根据坡折带成因机制,将其划分为断裂坡折带、挠曲坡折带和侵蚀坡折带,并结合地震剖面特征进一步划分为5亚类。在确定三叠系沉积前具有控砂作用的坡折带平面位置的基础上,根据坡折带在纵横向上分布特征进行分级。其中断裂坡折带作为该地区坡折带的主要类型,对砂体的平面与空间分布起到了重要的控制作用,主要体现在对砂体相带、厚度、层数及砂体演化等方面。通过对夏子街斜坡区坡折带与砂体发育规律统计,建立了沟控、断控、坡挡、坡阶、坡交等5种控砂模式。

Mutli-grade slope breaks were found in Xiazijie slope area of Mahu depression, Junggar basin. 3-D seismic data, combined with logging data and field reconnaissance information were used to study the characteristics of these slope breaks. Based on the genetic mecha- nism, the slope break can be classified as fault slope break, flexure slope break and erosion slope break. Considering with the seismic pro- file features, it can be further divided into 5 sub-categories. The plane positions and the grades of the slope breaks with sand-body control effect before Triassic deposition can be determined based on their lateral and vertical distribution characteristics. The fault slope break is considered to he the main type in this area, and it plays a significant controlling part in sand body distribution in lateral and vertical, which includes sand facies, sand thickness, sand layer number and sand evolution, etc. Finally, 5 kinds of sand-body control models are established, such as groove control, fault control, slope barrier, slope step and slope intersection on the basis of statistics of these slope breaks and sand distribution.