Features of the Transient Electromagnetic Survey Applying in Situation of Highly Conductive Sediments in Southeast Asia

Electroprospecting works have been performed over one of the blocks in the Southeast Asia. Two techniques were used: Transient Electromagnetic Soundings in Time Domain (TEM) and Induced Polarization Electromagnetic method (EM-IP). The objective is to conduct a comprehensive study of the sedimentary cover using TDEM. This includes mapping of zones with potential reservoirs properties from TEM, and to qualify these areas with Induced Polarization (IP) anomalies, usually related to presence of hydrocarbon system.

From TEM investigations was found that sediments of surveyed area are highly conductive. Total conductivity exceeds 2000 S. Furthermore, the high noise level is common for the survey area. The most influence on the EM data has 50 Hz noise due to its unstable parameters: amplitude and frequency. Nevertheless EM technique has shown sensitivity to geoelectric parameters changes to the depth up to 4 km. It was possible with development of special algorithms of EM signals processing.

Overall investigations show possibility of TEM and EM-IP application even in highly conductive environment and complicated noise situation.