System Architecture for 3D Gravity Modelling

Abstract

A flexible software architecture for gravity modelling is establishedand the advantage is discussed of having several alternative programs tohandle complex 3D models. The flexible architecture consists of four parts, implemented in a distributed computer environment:the three-dimensional model builders and visualizers (GOCADsoftware, version 7.0), the model representation translators (GOCADsoftware or GEOMOD sofware), the forward simulation algorithmsof gravimetric data (alpplying Talwani-Ewing and Goetze- Lahmeyermethods in the finite-element representation class), and the inversion(model updating) scheme manager based on the Cordell - Hendersoninversion procedure.A good software architecture should at least keep the model building and updating software separate from the forward simulation software. Inversion schemes can then be realized by communication between the two parts of software.Several synthetic cascs are shown to demonstrate the use and thecapability of the architecture and methods applied. The gravity fieldsof complex 3D models, i.e. overhanging and non-overhanging saltdomes, are simulated. The gravimetric anomalies for both cases havevery similar shapes. Gravity modelling can distinguish between these,because the existing mass differences result in anomaly differencesboth for surface profiles and X-sections. The capability of the inversionprocedure is also shown in the discussed synthetic case. The inversion manager is able to create the global structural forms representedas a horizon with constant density contrast (a two-layer model) from residual gravity anomalies.