海底油气藏及天然气水合物的时频电磁辨识

提出了伪随机多频海洋电磁法观测方案.采用伪随机多频信号作为激励场源,多偏移距同线偶极-偶极同时观测,相关辨识海底地电系统的频率特性和冲激响应,可以在时间域和频率域同时辨识海底高阻薄层.在时间域,瞬变冲激时刻可以直接指示海底地层电导率的变化;在频率域,利用多个频率的电场响应计算的频散率及其道闻变化量,相对相位道间变化量对高阻薄层有很好的反映.从而实现对海底油气及天然气水合物的多参数辨识.

Identification of seafloor hydrocarbon reservoir and gas hydrate using controlled-source electromagnetics in time and frequency domain

The pseudorandom multi-frequency marine controlled-source electromagnetic method is proposed in this paper. Two types of pseudorandom multi-frequency are adopted as source signal. The electric field response are simultaneously observed with multi electric dipole receivers configuring inline with the source dipole. The frequency characteristics and impulse response of the seafloor geoelectric system are identified at the same moment. So the seafloor thin resistor can be detected both in the time domain and frequency domain. The transient impulse peak time can be an indicator for seafloor conductivity in the time domain. The percent frequency effect, differentiation of percent frequency effect with offset and differentiation of relative phase with offset computed with multi frequency electric field response can be used to detect the seafloor thin resistor in the frequency domain. So the seafloor hydrocarbon reservoir and gas hydrate can be identified by multi parameters.