Gravity monitoring at oil and gas fields: data inversion and errors

The present paper considers certain problems of gravity monitoring at oil and gas fields arising due to inversion of repeat measurement data, when finding the positions of water-oil and water-gas contacts. The main sources of noise in gravity data are errors in vertical positioning of the tool, changes in atmospheric pressure, and variations in groundwater level and soil moisture. An algorithm based on using a multisensor borehole tool is proposed for a more accurate inversion. Examples of locating successfully the water front while solving model problems with the help of this algorithm are provided.