不同海洋可控源电磁法对海底低阻目标体的探测能力对比分析  

Comparative analysis on detection capability of two marine CSEM methods to seabed conductivity targets

作　　者：周建美[1] 李貅[1] 戚志鹏[1] 

机构地区：[1]长安大学地质工程与测绘学院,陕西西安710054

出　　处：《石油物探》2017年第6期882-889,共8页Geophysical Prospecting For Petroleum

基　　金：国家自然科学基金重点项目(51139004);中国博士后基金项目(332100150023);中央高校基金项目(310826151055)联合资助~~

摘　　要：深海低阻热液硫化物矿海洋可控源电磁法勘探主要采用时间域海底中心回线或重叠回线装置。以往对不同海洋电磁勘探装置探测能力的对比研究主要针对海底高阻油气藏目标体,而对于深海低阻目标体探测能力的讨论和分析较少。为此,研究对比了频率域和时间域深拖拽发射-接收装置对深海低阻目标体的探测能力,通过计算典型深水域三维低阻目标体模型的电场响应、归一化电场响应和空间中电场分布特点,分析了两种不同海洋电磁方法的应用效果,得到以下结论:(1)频率域和时间域深拖拽发射-接收装置均能探测到深海三维低阻目标体的电场异常;(2)对于典型的深海低阻目标体,频率域电磁法的异常幅值大于时间域电磁法。Marine electromagnetic exploration of deep-sea conductivity hydrothermal volcanogenic massive sulfide ore deposits has been widely undertaken, for which the time domain center loop or the overlapping loop system is the most common choice. Many scholars have made comparative studies on the detection capability of different CSEM exploration systems mainly on resistive targets, but performed few analyses on seabed conductivity targets. In view of the above situation, this study performed a comparative analysis on the detection capability to seabed conductivity targets using deep-towed horizontal transmitting-receiving configurations in both the frequency domain and the time domairxBy calculating the electric field response,normalized electric field response,and electric field distribution in a typical 3D conductivity target model of deep waters, we analyzed the application effects for two CSEM methods and derived the following conclusions： 1Deep-towed horizontal transmitting-receiving configuration in both the frequency domain and the time domain can be used to detect the electric field anomaly of the 3D conductivity target in the deep sea. 2For typical deep-sea conductivity targets, the abnormal amplitude from the CSEM method in the frequency domain is greater than that in the time domain

关 键 词：海洋可控源电磁法 发射-接收装置 深海低阻目标体 探测能力 三维正演 

分 类 号：P631[天文地球—地质矿产勘探]