IDENTIFICATION OF IGNEOUS ROCK RESERVOIRS IN EASTERN DEPRESSION OF LIAOHE BASIN BY TIME-FREQUENCY ELECTROMAGNETIC METHOD

Time-frequency electromagnetic method(TFEM), characterized by strong excitation signal, large detection depth and high precision, is one of the most promising techniques for the fine identification of igneous rock reservoirs and surface oil-gas detection, which can determine the oil-gas content by detecting the electrical and electrochemical anomalies of oil-gas reservoirs. Through analyzing the electrical logging data of HX sag in Liaohe Basin, it is confirmed that TFEM has the physical basis to identify different igneous rocks. The fault structure characteristics as well as the igneous rock inner structures of Shahejie Formation are obtained by the well seismic-TFEM joint inversion, and 5 stages of volcanic activities within the third member of Shahejie Formation are identified. A set of classification standard for polarizability evaluation is summarized through the extraction of amplitude and phase anomalies related to resistivity and polarizability, and comparison of oil production condition of the known wells. Combined with the seismic data, the oil-gas migration mechanism in HX sag is reversed by TFEM. The oil-gas evaluation template in the area is obtained through the research, by which several oil-gas favorable areas are identified and verified by subsequent drilling work. The method can provide reference for oil-gas evaluation in similar areas.