3D Full Tensor Gradiometry: a high resolution gravity measuring instrument resolving ambiguous geological interpretations

Abstract

The high-resolution, high-precision gravity gradient measuring technology, Bell Geospace's 3D FTG (Full Tensor Gradiometry), is presented as an exploration tool to enhance and solve ambiguous geological interpretations from conventional methods. Its high frequency character produces a Total Gravity Field that identifies subtle density contrasts within section, allowing it to be used in detailed hydrocarbon and mineral exploration projects, both offshore and onshore. This paper presents two case histories describing the results from an airborne and a marine survey. Both studies demonstrate the technology's ability not only in determining target shape but also in mapping target prospects across large sedimentary basins. The first example presented in this paper images a salt dome onshore Louisiana, USA, making inferences about its emplacement through direct mapping of controlling structure. The second identifies and maps a series of low-density sedimentary deposits on the flanks of the Judd Basin offshore NW Europe. The implications for exploration initiatives are significant as FTG data reduce risk in geological interpretation, thus facilitating a rapid decision making process.