An automatic new approach to gravity anomaly’s profile separation, inversion and interpretation, using an infinite horizontal slab model

Abstract

ABSTRACT The goal of this research is to develop a new, fast-applying, non-conventional 2D semi-inversion technique that uses data from a previously known control point (e.g. a borehole). The method successfully separated a digitised profile over the Bouguer gravity anomaly map into its components, each of which corresponded to a rock formation being prior chosen from a borehole or control point. The importance of this technique stems from its capacity to automatically analyse the shape of the Bouguer gravity anomaly, as well as its propriety, approximation and given accepted equivalent geological cross-section, utilising an infinite slab model. A preliminary synthetic guidance model (SGM) in this proposed new method is being created from borehole data to simulate the homogeneous density distribution of the rock formations that fill a hypothetical sedimentary basin so that it represents to far extent the history of the region’s sedimentation process. The theoretical gravitational effect for each rock formation is estimated using the infinite horizontal slab model for all rock formations of such a hypothetical basin model. The total of these gravitational effects is utilised to invert any gravity profile that crosses the Bouguer gravity anomaly map. The gravity anomalies of the Bouguer profile are then separated and inverted into the comparable rock formation thicknesses or/and depths tracked along the gravity’s profile using a simple method. The technique was tested on a synthetic model, a synthetic noisy contaminated model, and real data from two different field cases with different geological and lithological characteristics. The first was in the Tucson Basin in Southeast Arizona, USA, and the second on the Mors Salt Dome in North Jutland, Denmark. The method has demonstrated results comparable with prior known information of the borehole existing in the study areas.