Experimental study of marine magnetotellurics in southern Huanghai
南黄海海底大地电磁测深试验研究

Seismic energy is disturbed and attenuated seriously under the bad geological conditions for seismic exploration in southern Huanghai (Yellow Sea) basin, and therefore the Meso-Paleozoic wave group of marine reflection seismic cannot be recognized and the seismogram does not meet the requirement for evaluation of pre-Tertiary oil/gas resources in southern Huanghai basin. In May 2006, marine magnetotelluric (MT) sounding experiment was carried out and reliable data were acquired. In the experiment, 3 MT stations were deployed in regions of Wulian slope and Jiaozhou depression. On the basis of analysis on discrimination between marine and land MT data processing and discussion of marine electromagnetic noises, the correct methods of marine MT data about instrument obliquity and orientation and marine noise are presented. The result of MT data processing and inversion integrating geological and petrophysical data shows the existence of Paleozoic formations and is significant for the evaluation of pre-Tertiary oil/gas resources in the southern Huanghai basin. The experiment provides the evidence that marine MT technique can play an important role in the investigation of Paleozoic sediment basins.