1. State Key Laboratory of Petroleum ��esources and Prospecting��China University of Petroleum��Beijing 102249��China; 2. Faculty of Earth Sciences��China University of Petroleum��Beijing 102249��China; 3. ��esearch Institute of Petroleum Exploration �� Development��Beijing 100083��China

The Oriente Basin is a back- arc foreland basin��located in front of the Andes in South America�� A large number of low- amplitude structures with close relationship to hydrocarbon accumulation are developed in the eastern slope zone of the Oriente Basin�� Based on deep analysis of development characteristics and corresponding structural physical simulation��formation process and main controlling factors of the low- amplitude structures are ad- dressed�� The results show that the low- amplitude structures in the eastern slope zone of the Oriente Basin are usual- ly accompanied by thrust faults��inversion faults and strike- slip faults�� They are generally situated on the hanging walls of these faults�� The main dynamic mechanism controlling the development of the low- amplitude structures in- volves inversion and strike- slipping movement of faults�� In addition�� the pre- exiting normal faults with lower dip an- gle in deep layer have also exerted positive influence on late fault inversion and development of low- amplitude struc- tures��