Structural And Lithological Inversion Using Gravity And Magnetic Data Integrated With Geological Infomation

Abstract

This paper presents the techniques and results of a depth to basement inversion effort over the South China Sea area of Southeast Asia. Integrating the results of the inversions with geoseismic, well and geological data results in an accurate and informative description of the tectonics and structure of the area. Results show that significant packages of sediments of exploration interest exist that have not been exploited. Basin geometry and structure can be derived from the inversion of gravity and magnetic data. Using some newly developed techniques these inversions can also discriminate between different lithologies. Magnetic data can be inverted for magnetic basement and for intermediate layers of volcanic material. Gravity data can be inverted for structures which produce density contrasts in basins. Combining these results, basin structure can be explored to determine depth to basement, to high density structures such as carbonates, and to high susceptibility structures such as volcanics. New high resolution data sets for gravity and magnetic data have been merged and now cover all of greater Southeast Asia. These data allow us to extend our interpretation to all offshore basins and some onshore as well. We use the structural interpretations described above along with enhancements of gravity, magnetic and digital elevation model data. Combining these interpretations and enhancements with published data in a GIS environment allows us to constrain additional interpretations of tectonic development, and sedimentary facies and structures in basins. Examples are shown for basins around the South China Sea. Early results from offshore South America will also be presented.