Abstract：Yangqiao prospect in Riyang depression is an area high-degree is an area where very high-degree exploration has been done. The complicated complicated seismic and geological conditions in the border area of the depression cause very poor seismic data, so that exact structural configuration can not be known. Thus, high-precise gravimetric-magnetic surveys were done. Mean square errrr in gravity observation is ±6.3μGal, the mean square error in latitude correction is ±3.5μGal, and the mean square error in Bouguer correction is ±5.5μGal. Terrain correction is respectively performed in near, mid and far areas. The mean square errors of terrain correction in the near, mid and far areas are less than ±10μGal, ±5μGa1 and ±4μGal respectively. The gross mean square error of Bouguer anomaly is only ±15μGal. The sensitivity of the magnetometer used is 0.1 nT. The difference between two adjacent observed values which have undergone daily-variation correction is less than 1.0 nT. The mean square error of magnetic observation is ±0.3 nT. We can see that observed gravimetric and magnetic values all satisfy highaccuracy requirements. The interpretations of gravimetric and magnetic data are mainly based on the properties of gravitational and magnetic fields. Local gravimetric and magnetic anomalies at Wangzhuang were discovered by performing forward fitting of observed gravimetric and magnetic data. The repeated seismic interpretation by reference to the gravimetric-magnetic interpretation result confirms the existence of an anticline structure in the local gravimetric and magnetic anomaly area. The effect of direct hydrocarbon prediction using high-precise gravimetric and magnetic data were checked in known Anpeng and Yiaermen oil fields. The check shows good effect.
