1,720,983 research outputs found
Estimation of petrophysical parameters by linearized inversion of angle domain pre-stack data
No full textWe describe a linear Bayesian inversion method to estimate the relevant petrophysical
properties of the media forming a reflecting interface from the observations of
amplitude variation with incidence angle. Three main steps characterize the proposed
approach:
– information from borehole logs are statistically analysed to estimate the empirical
models that describe the functional relationship between petrophysical (e.g. porosity,
saturation, pressure or depth) and seismic variable(P and S velocities and density);
– the pure-mode (PP) reflection coefficient is parameterized in terms of the relevant
petrophysical variables and is linearized in order to implement the linear inversion;
– the sought petrophysical parameters are estimated from the seismic reflected amplitudes
by applying the linearized inversion where a priori information, data and
model errors and solutions are described by probability density functions.
We test the method on synthetic and real data relative to reflections from a
shale/gas-sand interface where the amplitude versus angle response, besides the lithological
contrast, is mainly controlled by the saturation and porosity of the sand layer.
The outcomes of the linearized inversion are almost identical to those obtained by a
previously developed non-linear inversion method demonstrating the applicability of
the linear inversion. It turns out that the gas-sand saturation in the range 0%–95%
is a poorly resolved parameter while the porosity is the best resolved parameter. The
issues of robustness and resolution of the inversion are discussed either through singular
value decomposition analysis or the observation of the a posteriori probability
density functions.
The linear inversion algorithm, compared with the previously developed non-linear
method, reduces significantly the computation time allowing for more extensive
applications
Inversione AVA petrofisica linearizzata: applicazione ad un caso reale e verifica di sensitività
No full text
Sismogrammi sintetici di una successione sedimentaria superficiale di fondo mare: analisi cinematica e dinamica di eventi convertiti
No full textElaborazione di dati sismici marini ad alta risoluzione e stima del campo di velocità delle onde di pressione
No full text
Stime di ellitticità e rimozione di onde superficiali tramite filtro di polarizzazione su dati sismici multicomponente
No full textIntegrated Geophysical Exploration Technologies for deep fractured geothermal systems (I-GET) SECOND ANNUAL REPORT: Nov. 2006 – Oct. 2007
No full textThe activities carried out by the University of Pisa (Unipi) in the reporting period refer to the following work-packages:
WP 3 GEOPHYSICAL MEASUREMENTS & DATA PROCESSING
The following activities have been carried out by Unipi :
- azimuthal analysis of the seismic signal amplitudes reflected from the geothermal targets;
- AVO analysis on a selected 2D profile from the 3D seismic volume.
WP 5 –INTEGRATED INTERPRETATION
Unipi has participated in the interpretation carried out by the ENEL colleagues of the observed seismic anomalies and in particular in the assessment of their relations with the producing geothermal targets
Integrated Geophysical Exploration Technologies for deep fractured geothermal systems (I-GET) FIRST ANNUAL REPORT: Nov. 2005 – Oct. 2006
No full textThe activities carried out by the University of Pisa (Unipi) in the reporting period refer to the following work-packages:
WP 2 AVAILABLE DATA FROM SELECTED EUROPEAN SITES WITH RESPECT TO EXPLORATION TECHNOLOGY
Unipi has contributed to the selection of appropriate subsets of the 3D seismic data acquired in the Travale test site. The selected data are the input for the processing carried out by Unipi in the frame of WP3.
WP 3 GEOPHYSICAL MEASUREMENTS & DATA PROCESSING
The following activities have been carried out by Unipi from November 2005 to October 2006:
- selection and reprocessing of appropriate subsets of the Travale seismic 3D dataset
- simulation of several acquisition geometries for the Gross Shonebeck site, participation to the acquisition and analysis of the recorded data
- …
