資源開発技術・岩盤工学

[3201-10-05] 3D Gravity forward modelling with spherical particles for integrated analysis with other geophysical observations

○Qian Yin¹, Hitoshi Mikada¹, Junichi Takekawa¹ (1. Kyoto University)

司会：加藤 昌治（北海道大学）

Keywords:gravity, forward modelling, integration

Time-lapse gravity surveys have been applied to a wide range of study fields, such as reservoir fluid surveillance and volcanic activity monitoring. In gravity data processing, although surface deformation plays an essential role in gravity correction process because of its superficial position, however the deformation effects to gravity data processing have been underestimated in current studies. In the meantime, it is possible to evaluate the surface deformation from the hydrodynamic properties of reservoirs or volcanic chambers under a mesh-free environment. To implement the nowadays feasible studies, from the hydrogeology and reservoir simulation, of deformation phenomenon from reservoirs’ or volcanic chambers’ dynamic properties into geophysical potential field methods, it is important for us to study the two subjects in a conjunct framework. Since this is a preliminary study of the subject, in this study, our main object is to convert the existing model unit (prisms) of gravity monitoring technique into mesh-free particles (spheres) and to introduce a sphere-wise forward modelling to gravity methods.

We calculate gravitational attraction of numerical mass bodies with various densities from a prism-based approach and a sphere-based approach. This abstract first discusses some plausible methodologies to convert a gravity modelling unit from a prism to sphere or spheres and their corresponding application conditions. The results show that gravity of a single prismatic model can be generated or revealed by a particle model or a combination of particle models. This observation enables us to conduct forward modeling of any mass body with an arbitrary shape by stacking both model unit of a prismatic or a spherical shape. In the end, we calculate gravity force from the two approaches to some density models of more realistic and practical values. The results show that it is feasible to conduct gravity forward modeling of density objects through a particle model.