THE GRAVITY AND MAGNETIC DATA PROCESSING AND THE INTEGRATED GRAVITY, MAGNETIC AND SEISMIC INVERSION OF THE HEFEI BASIN

The Hefei Basin has experinced three regional reconnaissance survey since 1958. In recent years, Shengli oilfield increased investment to the basin and threw in a large amount of funds to carry out seismic and nonseismic exploration, including the high-precision gravity, magnetic and geochemical prospecting covering the whole basin, a 8km×8km 2-D seismic measuring network running through the whole area in length and breadth and eight electrical profiles. In view of the exploration situation of the basin, a wealth of gravity, magnetic and electrical data were used to focus on the target processing of gravity and magnetic data instead of routine processing models.The gravity and magnetic anomaly information and electrical characteristics of regional tectonics, local structures and faults in this area were obtained rapidly and correctly, and the related graphs were drew. This provided reliable, full and accurate bases for the comprehensive hydrocarbon assessment of the Hefei Basin, and resulted in a new set of thinking about gravity and magnetic processing suitable to new area prospecting. Meanwhile, as the Hefei Basin was short of physical property data and rich in geophysical data, a statistical deduction inversion methoel which did not rely upon physical property parameters was proposed. Combined with the 31 seismic traverse data and the gravity and magnetic data of the whole area, a statistical relationship formula was established, the burial depth of the Indosinian discontinuity was calculated by inversion, the integrated gravity, magnetic and seismic inversed Indosinian discontinuity structural mep was drew successfully, and the structural distribution patterns of the areas not involved by the seismic measuring network were depicted in detail. Basides, HF-700 and HF-340 two sections were subjected to integrated gravity, magnetic, electrical and seismic interpretation, and well geological effects were obtained.