Vertical density gradient in interpreting high-precision gravity

Given non-linear (exponential) pattern changes in the density of rocks of sedimentary complexes with depth σ(Z) are studied. A series of direct and inverse problems of detailed and highly accurate gravity typical for Petroleum Geology with and without the vertical density gradient is fulfilled. Received error modeling (interpretation), assuming a constant density, lead to the conclusion not appropriate to improve the accuracy gravimetric survey better than ± 0,20 IPF, if there is no possibility of creating and recording petrogravity dependency σ(Z).