1. College of Earth Sciences��Jilin University��Changchun 130061��China; 2. ��esearch Institute of Exploration and Development��Liaohe Oilfield Company��PetroChina��Panjin 124010��Liaoning��China; 3. Geology ��esearch Institute��Erlian Branch��Huabei Oilfield Company��Petrochina��Xilinhaote 026000��Inner Mongolia��China

Based on the basalt cores of 305. 79 m long�� 176 rock slides and their corresponding logging data of 45 wells in the eastern depression of Liaohe Basin�� the basalts are divided into the massive�� vesicular and brecci- ated basalts in category�� The massive basalt is dense and massive��underwent a low degree of alteration��and its logging is characterized by high density (in average of 2. 71 g·cm ^��3 ) and low natural gamma (in average of 36 API)�� The vesicular basalt is developed in vesicles��mostly filled with zeolite and calcite��underwent the most seri- ous alteration��and its logging is characterized by low density (in average of 2. 47 g·cm ^��3 ) and high acoustic time (in average of 72 μs·ft ^��1 )�� The brecciated basalt is in autobrecciated form��developed in inter- breccia spaces�� and its logging is characterized by low resistivity (in average of 8 Ω·m)�� The mechanisms of well- logging re- sponse of the basalts depend on mineral composition��structure��alteration type and degree��reservoir space and later modification��and hydrocarbon saturation��etc��