The impact of spatial sampling and signal-to-noise ratio on image quality in onshore seismics

An onshore seismic survey is best conducted symmetrically, due to the reciprocity theorem of the wave field. Within the family of symmetric geometries the cross spread is most used. Recent developments show a marked increase of the number of available channels, nowadays 100,000+. This enables the use of point receivers, meaning that every...

Frequency Domain Two-Stage Beamforming for Phased Array Imaging Using the Fast Hankel Transform

The huge amount of data that needs to be transferred between probe and imaging system becomes a major issue when the data transfer capacity is limited, e.g. in handheld systems, wireless probes and miniaturized probes. The amount of data can be significantly reduced by using two-stage beamforming. The first stage consists of a fixed focus...

Combined imaging and velocity estimation by Joint Migration Inversion

Seismic imaging projects aim to reveal the structure of the earths crust from seismic data. These projects typically include three separate processing steps, being: • attenuation of multiple reflections in the seismic data. • estimating seismic wave propagation velocities from the seismic data. • mapping the measured reflection data to the...

Nonlinear imaging condition and the effect of source illumination: Imaging fractures as nonwelded interfaces

Fluid flow through a fractured reservoir is often controlled by the large fractures. Seismically imaging these large fractures has the potential to illuminate their hydraulic properties.We derived a nonlinear imaging condition considering a medium containing nonwelded interfaces such as fractures for high-resolution fracture imaging. This was...

Non-linear imaging condition to image fractures as non-welded interfaces

Hydraulic properties of a fractured reservoir are often controlled by large fractures. In order to seismically detect and characterize them, a high-resolution imaging method is necessary. We apply a non-linear imaging condition to image fractures, considered as non-welded interfaces. We derive the imaging condition from the general correlation...

Green's function retrieval with Marchenko equations: A sensitivity analysis

Recent research showed that the Marchenko equation can be used to construct the Green’s function for a virtual source position in the subsurface. The method requires the reflection response at the surface and an estimate of the direct arrival of the wavefield, traveling from the virtual source location to the acquisition surface. In this paper,...

Imaging velocity and attenuation scatterers with wave equation migration

The thesis deals with wave-equation migration in a visco-acoustic medium, where an ambiguity appears when one tries to image simultaneous velocity and attenuation perturbations.

Comparison of 10–18 GHz SAR and MIMO-based short-range imaging radars

This paper presents an experimental investigation of two approaches to short-range radar imaging at microwaves by means of ultra-wideband (UWB) technology. The first approach represents a classical synthetic aperture radar (SAR) that employs a transmit–receive antenna pair on mechanical scanner. The second one makes use of a multiple input...