Land time-lapse CSEM: Collecting, modeling and inversion of CSEM data for a steam-injected oil field

Geophysical methods are widely used for hydrocarbon exploration and time-lapse measurements. One method that can be applied in place of or in addition to the routinely used seismic method, is the Controlled-Source ElectroMagnetic (CSEM) method. The work described in this thesis explores various aspects to improve the land CSEM method for...

Seismoelectromagnetic homogeneous space Green's functions

We have developed explicit expressions and the corresponding computer code for all homogeneous space Green’s functions for coupled electromagnetic fields and poroelastic waves. The Green’s functions are derived from the basic equations in closed form in the wavenumber- and space-frequency domains. They are given for point sources of any type....

Three-dimensional inversion of inductions logs in real-time

In petroleum production and exploration, having good information about a hydrocarbon reservoir is paramount to successful exploitation. A popular tool is to probe the electric conductivity in a well to obtain direct information of the well surrounding. As wells are nowadays mostly horizontally drilled, this information is becoming more important...

The electromagnetic response in a layered vertical transverse isotropic medium: A new look at an old problem

We determined that the electromagnetic vertical transverse isotropic response in a layered earth can be obtained by solving two equivalent scalar equations, which were for the vertical electric field and for the vertical magnetic field, involving only a scalar global reflection coefficient. Besides the complete derivation of the full...

An approximate 3D computational method for real-time computation of induction logging responses

Over many years, induction logging systems have been used to create well formation logs. The major drawback for the utilization of these tools is the long simulation time for a single forward computation. We proposed an efficient computational method based on a contrast-type of integral-equation formulation, in which we applied an approximation...

Electromagnetic interferometry in wavenumber and space domains in a layered earth

With interferometry applied to controlled-source electromagnetic data, the direct field and the airwave and all other effects related to the air-water interface can be suppressed in a data-driven way. Interferometry allows for retreival of the scattered field Green’s function of the subsurface or, in other words, the subsurface reflection...

Marine Controlled-Source Electromagnetic Interferometry

In marine Controlled-Source Electromagnetics, a boat tows an electric source, whose signal is travelling on various paths to the receiver stations at the ocean bottom. Unfortunately, the signal does not only travel via the subsurface to the receivers, but also directly through the water and via the air-water interface. Signals travelling on the...

Analytical synthesis technique for linear uniform?amplitude sparse arrays

A novel analytical approach to the synthesis of linear sparse arrays with uniform?amplitude excitation is presented and thoroughly discussed in this paper. The proposed technique, based on the auxiliary array factor concept, is aimed at the deterministic determination of the optimal array element density and excitation phase tapering...

Three dimensional rigorous model for optical scattering problems

We present a three-dimensional model based on the finite element method for solving the time-harmonic Maxwell equation in optics. It applies to isotropic or anisotropic dielectrics and metals, and to many configurations such as an isolated scatterer in a multilayer, bi-gratings and crystals. We shall discuss the applications of the model to high...

Electro-quasistatic field simulation of an endosteal cochlea implant

Cochlea implants can help deef patients to regain hearing. The implants consist of a microphone, a speech processor and an electrode array implanted in the inner ear in order to directly excite the auditory nervs. Recently, an electrode array has been designed to be implanted without inner ear trauma aiming at combining rest hearing with the...

Electrodynamics in deformable solids for electromagnetic forming

The behaviour of matter in an electromagnetic field may be considered as a very complex problem, involving not only electromagnetism but also mechanics and thermodynamics. The interaction field-matter is not simple even for a rigid body, and it becomes more complicated for a deforming body, as long as all the physical quantities that...

Directional Decomposition of Electromagnetic and Acoustic Wave-Fields - Applications in integrated optics, exploration seismics and underwater acoustics