− | Gravity offers significant applications to petroleum exploration. Gravity measurements are affected by changes in rock [[density]]. Surface gravity surveys and subsurface surveys made with a [[borehole gravity]] meter are effective in locating [[fault]]s and geologic structures with density contrasts to their surroundings. The borehole gravity meter has broad application, from locating [[porosity]] in wildcats or through [[casing]] in old wells to monitoring fluid changes in productive [[reservoir]]s. This chapter discusses the traditional application of gravity, from surface surveys to the application of borehole gravity measurements. | + | Gravity offers significant applications to petroleum exploration. Gravity measurements are affected by changes in rock [[density]]. Surface gravity surveys and subsurface surveys made with a [[borehole gravity]] meter are effective in locating [[fault]]s and geologic structures with density contrasts to their surroundings. The borehole gravity meter has broad application, from locating [[porosity]] in wildcats or through [[casing]] in old wells to monitoring fluid changes in productive [[reservoir]]s. |