f Interpretation of borehole gravity data in crystalline environment

Borehole gravity meter (BHGM) surveys are mainly used in sedimentary environments. Only a limited number of case histories for crystalline rocks is known (Richter 1989). The pilot well of the Continental Deep Drilling Project (KTB) of the FRG has penetrated amphibolites of densities 2.81 to 2.95 g/cm³ embedded within gneisses of lower density (2.12 to 2.74 g/cm³). The apparent densities calculated from the BHGM data are combined with independent information from other sources for the interpretation of dipping structures. The result is an interpretation procedure which is also valid for the sedimentary environment of hydrocarbon exploration.