摘要
对石油资源的需求激发了海底电磁勘探技术的研究与应用。为了研究海底瞬变电磁测深的可行性,根据海底电磁方法的观测特点,设计了一组三维异常体模型,采用积分方程算法计算了不同模型参数时赤道装置和轴向装置的瞬变电磁响应,模拟了不同海水深度、不同偏移距对异常的影响。模拟结果表明,海底瞬变电磁测深能很好地探测到海底下方电性异常体的存在,异常体的响应特征与陆上电磁响应的特点一致。海水层的影响主要体现在对发射电磁能量的吸收,导致异常信号能量较弱,但同时也屏蔽了外界的环境噪声,净化了测量环境。在海底采用移动源方式,可以容易实现不同偏移距和不同观测角度的测量,为叠加处理与成像提供条件。
The increasing demand of petroleum resources has activized studies and applications of ocean bottom electromagnetic exploration technologies. To study the feasibility of ocean bottom transient electromagnetic method (OBTEM), a group of three-dimensional models of anomalous body beneath sea floor are designed and electromagnetic responses are calculated for various parameters and for equatorial and axial configuration by using integral equation algorithm. The features of anomalies for different ocean depth and different source-receiver offset are examined through simulated results. Modeling results show that anomalous body beneath the sea floor can be well identified by OBTEM, characteristics of anomalous fields are similar to that of TEM measurements on land. The effect of the seawater layer is mainly the absorption of emitted electromagnetic energy and consequently weakens the observed signal, but it is plausive to have shielded the external noises and purified the measuring environment. The mobile source mode for OBTEM makes field measurements for various source-receiver offsets and angles easy, thus it is possible to stack data for enhancing the image of the anomalous body.
出处
《石油天然气学报》
CAS
CSCD
北大核心
2005年第2期190-193,共4页
Journal of Oil and Gas Technology
基金
国际科技合作重点项目(2002DF000022)。
