Impulse response of seafloor hydrocarbon reservoir model
海底油气藏地质模型的冲激响应

The time-domain impulse response feature of marine controlled-source electromagnetic(mCSEM) can be used to identify the seafloor thin resistor of hydrocarbon reservoir.The step response and impulse response of homogeneous earth half space,marine double half space and four-layer earth models to horizontal electric dipole source were computed in this paper.A concept of transient impulse time was put forward.The denote relationship between the conductivity of the earth and the transient impulse time of the conductive medium to horizontal electric dipole was analyzed.It is suitable surveyed with multi offsets simultaneously for seafloor thin resistor of hydrocarbon reservoir exploration in that the electromagnetic energy diffused so faster in lower conductive medium,and the transient impulse time can come early at appropriate offsets.The differential of transient impulse time with offsets was calculated,and it was used as a clearly indicator for presence and depth of thin resistor.The effect of sea water depth on transient impulse time was also analyzed.The observation of transient impulse time was limited to a certain offsets for the airwave effect.How to eliminate the airwave effect is now a main research point in both time domain and frequency domain mCSEM data process.