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Deidda, G. P.
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Deidda, G. P.
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- PublicationOpen AccessFeasibility study (I stage) of CO2 geological storage by ECBM tecniques in the Sulcis Coal Province (SW Sardinia).(2006-06)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Quattrocchi, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Bencini, R. ;Amorino, B. ;Basili, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Caddeo, B. ;Cantucci, B.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Cara, R. ;Cauli, G. ;Cinti, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Deidda, G. ;Deriu, G. ;Fadda, A. ;Fandino, V. ;Ferenzena, S. ;Giannelli, A. ;Galli, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Mazzotti, M. ;Ottinger, S. ;Pizzino, L. ;Pini, R. ;Sardu, G. ;Voltattorni, N.; ; ;; ;; ; ;; ; ; ; ; ; ;; ; ; ; ; ;An ECBM feasibility study started for the Sulcis Coal Province (SW Sardinia, Italy): available geochemical, structural-geology, stratigraphic and reservoir engineering considerations as well as the newly gathered experimental data are discussed, including: fluid geochemistry (major and minor elements, dissolved gases, C and He isotopic ratios) of different strata/reservoir, coal composition and experimental data on CO2/CH4 adsorption-desorption on coal. A MapInfo GIS structure was built up including stratigraphic, geo-structural, hydro-geochemical, coal-compositional and environmental-impact information as well as the CO2 sources location and typology. Despite preliminary, these data highlighted both the challenging positive and negative aspects of the Sulcis Coal Province versus the exploitation of the ECBM technique. The most important objective of this phase I of the project is the selection of the best Sulcis ECBM test-pilot site, which will be followed (Phase II-2007) by the choice of a scaled up site and possibly by a future network (Phase III-2008). CO2 geological storage and CH4 production potentials in Sulcis have been grossly evaluated as a whole, in the frame of the Sardinia region CO2 sources, including the coal-fired power plants, both existent and foreseen (hundreds of millions of tonnes of CO2 are possible to be stored underground in the next decades).277 566 - PublicationOpen AccessInversion of electrical conductivity data with Tikhonov regularization approach: some considerations(2003)
; ; ; ;Deidda, G. P.; Dipartimento di Ingegneria del Territorio, Università di Cagliari, Italy ;Bonomi, E.; Centro di Ricerca e Sviluppo di Studi Superiori della Sardegna, Cagliari, Italy ;Manzi, C.; Centro di Ricerca e Sviluppo di Studi Superiori della Sardegna, Cagliari, Italy; ; Electromagnetic induction measurements, which are generally used to determine lateral variations of apparent electrical conductivity, can provide quantitative estimates of the subsurface conductivity at different depths. Quantitative inference about the Earth's interior from experimental data is, however, an ill-posed problem. Using the generalised McNeill's theory for the EM38 ground conductivity meter, we generated synthetic apparent conductivity curves (input data vector) simulating measurements at different heights above the soil surface. The electrical conductivity profile (the Earth model) was then estimated solving a least squares problem with Tikhonov regularization optimised with a projected conjugate gradient algorithm. Although the Tikhonov approach improves the conditioning of the resulting linear system, profile reconstruction can be surprisingly far from the desired true one. On the contrary, the projected conjugate gradient provided the best solution without any explicit regularization ( a= 0) of the objective function of the least squares problem. Also, if the initial guess belongs to the image of the system matrix, Im(A), we found that it provides a unique solution in the same subspace Im(A).166 668 - PublicationOpen AccessAn experiment of spectral induced polarization(1994-11)
; ; ; ; ; ; ;Balia, B.; Dipartimento di Ingegneria del Territorio, Università di Cagliari, Italy ;Deidda, G. P.; Dipartimento di Ingegneria del Territorio, Università di Cagliari, Italy ;Godio, A.; Dipartimento di Georisorse e Territorio, Politecnico di Torino, Italy ;Ranieri, G.; Dipartimento di Georisorse e Territorio, Politecnico di Torino, Italy ;Sambuelli, L.; Dipartimento di Georisorse e Territorio, Politecnico di Torino, Italy ;Santarato, G.; Istituto di Mineralogia, Università di Ferrara, Italy; ; ; ; ; A Spectral Induced Polarization (SIP) survey was carried out in a mining test site in Sardinia (Italy). Measurements were developed along a profile by using an axial dipole-dipole array with 10 AB positions and 6 MN positions for cach AB. The amplitude and phase spectra of the apparent resistivity were acquired in the 0.25-4096 Hz frequeney range. The results obtained through the processing and inversion step seem to confirm that, with respect to the classical TD/FD Induced Polarization, SIP allows better discrimination of some important characteristics of mineral deposits such as mineral content and grain size.181 308