SNIC
SUPR
SNIC SUPR
3D modelling and inversion of geophysical electromagnetic data
Dnr:

SNIC 2017/3-112

Type:

SNAC Small

Principal Investigator:

Maxim Smirnov

Affiliation:

Luleå tekniska universitet

Start Date:

2018-01-01

End Date:

2019-01-01

Primary Classification:

10505: Geophysics

Webpage:

Allocation

Abstract

The purpose of the project is to build a software facility at LTU with the capability to do advanced 3D modeling and inversion of geophysical data. The software developments are specifically directed towards (1) multi variate data analyses and (2) modelling and inversion of geophysical data. The project follows the concept of Common Earth Modeling (Mcgaughey, 2016) which enables easy and full integration of geophysical, geochemical and geological models. This is also inline with EPOS geoscientific database project where LTU is responsible for magnetotelluric data across the entire Europe. As an integral part of the project we will continue to develop state of the art simulation techniques for electromagnetic geophysical methods. This will facilitate the internal LTU use of geophysical methods for various research applications and education. This development is directly linked to the usage of HPC resources as realistic 3D simulations are often very resource demanding. High resolution and joint data inversions are required in particular to simulate mining targets with high accuracy. In our development we target the following requirements in addition to being able to produce reliable 3D models: • Ability to deliver models in relevant commercially accepted formats • Ability to incorporate 3D models from other software packages for soft and hard constraints in inversion • Ability to include borehole information as constraint in inversion • Ability to include petrophysical data as constraints • Ability to handle multiple data types • Ability to handle airborne, ground and borehole data • Include topography in modeling • Joint inversion of multiple data types • Inclusion of geological information as á priori information (to constrain the final geophysical model) The software packages will be build using modern object oriented techniques that facilitates easy maintenance and expansion of the software to include modeling and inversion of data from all geophysical methods. Priority is initially given to (1) the electromagnetic forward modeling code, (2) calculations of derivatives needed for data inversion and (3) the construction of a general purpose inversion module. In recent years, combining different geophysical techniques into a single computational approach that explains all observables simultaneously, usually termed joint inversion, has started to gain popularity. The idea of performing joint inversion is not new, but computational limitations have previously put severe restrictions on its practical use and thereby also hampered the development of the method. The approach will allow us to create more accurate 3-D models of geological targets, by using an advanced inversion and modeling techniques. We have chosen to build the software package in Matlab which is a high-level computer language with an interactive environment. There are several reasons for this choice: (1) The software can be built on existing software already in use by one of the proposers (Maxim Smirnov); (2) access to advanced visualization facilities; (3) access to parallel programming facilities for high-speed performance; (4) Matlab is introduced to most students at LTU; (5) Matlab is in use world-wide and by other research groups at LTU for a multiple type of applications.