基于高精度重磁资料的松辽盆地南部十屋断陷基底断裂研究

通过对松辽盆地南部十屋断陷1∶5万重磁资料的处理分析,使用离散的二维小波变换、相关滤波、异常剥离以及常规的重磁位场分离方法来揭示盆地基底及构造特征,结合地质、地震和钻孔资料,对十屋断陷基底断裂进行了综合预测。在十屋断陷基底内部确定了21条主要断裂,主要分为4组,即F1桑树台断裂、F2八屋断裂带、F3金山断裂、F4大榆树断裂。十屋断陷基底主干断裂系统主要由盆地西侧桑树台断裂和盆地内部一系列NE走向的断裂组成。桑树台断裂北部为NE走向,中部近SN走向,南部为NW走向,总体平面形态为弧形。盆地内部具有3组NE向正断层,这些正断层走向与桑树台断裂北段一致,应该和桑树台断裂形成于同一构造应力场作用下。研究结果为十屋断陷基底油气勘探提供了重要的依据。

Faults in Crystalline Basement of Shiwu Faulted Depression in Songliao Basin Determined by High Precision Gravity and Geomagnetic Data

Based on 1∶50,000 size gravity and magnetic data of Shiwu faulted depression in Songliao Basin,twenty-one major faults in Shiwu faulted depression were determined by methods of frequency domain transformation in gravity and magnetic field,discrete 2D wavelet transformation,correlation filtration and anomalies stripping.The faults in basement of Shiwu faulted depression were determined,and could be divided into the following four groups,Shangshutai big fault zone(F1),Bawu fracture zone(F2),Jinshan fault zone(F3) and Dayushu fault zone(F4).Shangshutai fault in western border of Shiwu faulted depression and a series of faults in NE direction inside the depression consist of the structure of basement faults in Shiwu depression.On the whole,Shangshutai fault develops as a segment of a circle in planar configuration,and its direction is NE in its north,SN in the middle,and SW in the south.Three fault groups of F2,F3 and F4 are determined as normal fault in NE direction in Shiwu faulted depression,moreover,the trend of these normal faults are coincide with the northern segment of fault F1,hence,these four fault groups would become into being in a same tectonic stress field,and the four main faults compose of the basement of Shiwu faulted depression.The results provide a significant evidence for prospecting hydrocarbon of the basement.