Abstract: In-depth analysis of remaining resources and exploration degree in the Raoyang sag indicated sustainable exploration potential, and made clear future key exploration domains and directionsin the low-lying zone, slope zone and subtle buried hill, and pointed out potential issues in further exploration, such as scattered seismic data, unclear structural relationship and distribution of effective reservoirs, unidentified controlling factors and models of hydrocarbon accumulation. In order to discover more resources and high-quality large-scale reserves, and further increase resource conversion ratio, principles focusing on "overall understanding, comprehensive evaluation and integral deployment" for secondary exploration in the Raoyang sag were put forward, namely,to establish an overall 3D seismic data platform of the whole sag, to rebuild structure model, sedimentary model and reservoir geological model of the sag, to quantify the spatial distribution of hydrocarbon resources, to build multi-field hydrocarbon accumulation models, and to carry out integral and fine exploration in optimized key areas and targets. Following these principles, since 2005, a series of important discoveries have been made and constructed 200 million tons of large-scale economic reserves area in the Raoyang sag. This paper analyzes and summarizes the methods, techniques and experiences of the secondary exploration in the Raoyang sag, which may provide reference to and enlightenment on further exploration in other similar sags.

Key words: Raoyang sag, low-lying zone, slope zone, subtle buried hill, secondary exploration