基于ASTER数据对中非裂谷系东部地表构造解释及油气信息提取

Surface Structure Interpretation and Oil and Gas Information Extraction from ASTER on East Central African Rift System

获取Doseo盆地和Salamat盆地ASTER遥感数据进行预处理,利用波段比值法及主成分分析法提取粘土蚀变、碳酸盐岩蚀变、铁离子(Fe^(2+)、Fe^(3+))蚀变等异常信息,圈定遥感异常区。异常解译显示,异常区域主要分布在Salamat盆地和Doseo盆地西南侧,异常强度以一级为中心向四周扩散。高渗漏区粘土矿物蚀变异常极为明显,其次为碳酸盐岩异常,铁离子蚀变异常最不明显。地表地质解释表明,中非剪切带为右行走滑断裂,断裂两侧发育与主断裂斜交的雁列式断层或褶皱,主剪切带在宏观影像上呈反"S"形,走向北东,断层转折部位为松弛拉伸区域,形成Salamat和Doseo拉分盆地,盆地内部发育大量扭张类构造样式。异常区域与断裂分布的对应关系较好,指示油气渗漏受断裂控制,断裂带为油气渗漏提供通道,使地表油气异常信息较为明显。该研究为中非裂谷系油气勘探提供参考。

By extracting and preprocessing ASTER remote sensing data of Salamat Basin and Doseo Basin,analyzing anomaly minerals information of clay,carbonate and ferrum,it carried out the remote sensing interpretation of structure and surface geological features,acquired hydrocarbon remote sensing anomaly area and conducted the petroleum geological evaluation. The results of surface structures and geological interpretation indicate that tectonic characteristic of the Central African Rift System is a shear zone while Salamat Basin and Doseo Basin are pull-apart basins that formed when the shear faulted. Salamat Basin and southern Doseo Basin are distributed with fractures and both sides of the fault have development of echelon fault or fold obliquely crossing with the main fracture. The main shear zone in the macro-view image appears converse "S" to the north east. Comparing with the known oil well,it shows that clay mineral alteration anomaly at the well is obvious,followed by carbonate alteration anomaly,and the iron ion alteration anomaly is weakest. Through analyzing on remote sensing area of Salamat and Doseo Basin,the Level 1 anomaly areas are mostly distributed in the fracture development zone,showing that seepage of oil and gas is controlled by fracture,and the fracture zone provides favorable channel for the seepage,which makes the ground oil and gas anomaly information obvious. The research has extracted alteration anomaly area which provides reference for further exploration.