REPORTE Y ANÁLISIS DE OCURRENCIAS ACCIONES CORRECTORAS Y PREVENTIVAS.

RESEARCH GROUP: Villiam Bortolotti, Paolo Macini, Ezio Mesini, Marianna Vannini KEYWORDS: MRR, porous media, permeability, wettability, UPEN

Nuclear Magnetic Resonance Relaxometry (MRR) is a universally accepted technique for the spatially non-resolved determination of structural and trans- port properties of porous media in a non-destruc- tive and non-invasive way. It is based on parameters like longitudinal and transverse relaxations time (T₁ and T₂, respectively) and magnetization densi- ty (Mo) and, nowadays, is widely used both in core

and log analysis to determine petrophysical proper- ties of rocks, such as porosity, pore size distribution, permeability, wettability changes and irreducible water saturation. Natural rocks are usually hetero- geneous and this generally leads to multiexponen- tial relaxation, which we have usually inverted by UpenWin software, to obtain the distribution of local Surface/Volume ratios.

UpenWin is a software for Windows internally developed that implements the UPEN (Uniform PENalty) algorithm and is distributed by the Uni- versity of Bologna. UPEN is a robust algorithm for the inversion of multiexponential decay data, that allows appropriate smoothing of the distribution, allowing sharp peaks without breaking broad fea- tures into multiple peaks not required by the data. Magnetic Resonance Imaging (MRI) is a spatially resolved method to get information on the distri- bution of oil or/and water into the porous medi- um and to follow flow and absorption of the satu- rating fluids. A powerful extension of the previous techniques is the Quantitative Relaxation Tomog- raphy (QRT), based on the combination of MRR with MRI. QRT generates relaxation time maps, i.e. images where the signal of each voxel (elemen- tary volume, corresponding to the elementary 2D pixel in the image) is proportional to T1 or T2 or

M_o of the fluid in that voxel.

The research activity of this group is focalized on the use of both MRR and MRI techniques to character- ize the petrophysical properties of the porous media, to monitor the saturating fluids flow and to quantify the interaction of the fluids with the surfaces of the pores space. Particularly studied are the wettability and the permeability of rocks, that mainly affects oil recovery, and natural and amended soils.

Geoengineering and Natural Resources – Petroleum Engineering, Fluids Mechanic in Porous Media and Nuclear Magnetic Resonance

Fig. 1. Magnetic Resonance Tomograph (Es- aote, Italy) at the LAGIRN Lab.

Fig. 2. Creation of a T2 relaxation times map of

a rock sample.

Fig. 3. T₁ relaxation distribution curve; time evolution of the wettability of a rock sample sat- urated with acid soltrol.

MAIN PUBLICATIONS

V. Bortolotti, P. Fantazzini, R. Mongiorgi, S. Sauro, S. Zanna. Hydration kinetics of cements by Time-Domain Nuclear Magnetic Reso- nance: Application to Portland-cement-derived endodontic pastes. Cement And Concrete Re- search, 42, 3, 577-582, 2012.

A. Bonoli, V. Bortolotti, P. Macini, E. Mesini, M. Vannini. Natural soil mixed with paper mill sludge characterization by 1h nuclear magnetic resonance longitudinal relaxation time. Pro- ceedings of the CRETE 2012 - 3rd Interna- tional Conference on Industrial and Hazardous Waste Management, Chania (Crete, GR), Sep- tember 12-14th, 2012.

V. Bortolotti, P. Fantazzini, M. Gombia, D. Greco, G. Rinaldin, S. Sykora. PERFIDI filters to suppress and/or quantify relaxation time components in multi-component systems: An example for fat-water systems. Journal of Mag- netic Resonance, 206, 2: 219-226, 2010. M. Gombia, V. Bortolotti, RJS Brown, M. Ca- maiti, L. Cavallero and P. Fantazzini. Water Vapor Absorption in Porous Media Polluted by Calcium Nitrate Studied by Time Domain Nu- clear Magnetic Resonance. Journal of Physical Chemistry B, 113, 31, 10580-10586, 2009. M. Gombia, V. Bortolotti, R. J. S. Brown, M. Camaiti, and P. Fantazzini. Models of water im- bibition in untreated and treated porous media validated by quantitative magnetic resonance imaging. Journal of Appl.Physics, 103, 9, pp 8. 2008.

V. Bortolotti, M. Gombia, F. Cernich, E. Michelozzi, P. Fantazzini. A study to apply nuclear magnetic resonance porosity measure- ments to seabed sediments. Marine Geology, 230: 21 – 27, 2006.

V. Bortolotti, M. Camaiti, C. Casieri, F. De Luca, P. Fantazzini, C. Terenzi. Water absorp- tion kinetics in different wettability conditions

studied at pore and sample scale in porous me- dia by portable single-sided and laboratory im- aging devices. Journal of Magnetic Resonance, 181: 287-295, 2006.

V. Bortolotti, A. Campagnoli, M. Gombia, P. Fantazzini, G. Barile, C. Masciopinto. Quanti- tative relaxation tomography (QRT) and field test to estimate a porosity-transmissivity rela- tionship in fractured aquifer. Proceedings of FEM-MODFLOW Conference, September 13-16, Karlovy Vary, Czech Republic, Edited by Karel Kovar, Zbynek Hrkal and Jiri Bruthans, pp 7-10, 2004.

G. C. Borgia, V. Bortolotti, P. Fantazzini. Changes of the local pore space structure quan- tified in heterogeneous porous media by 1H magnetic resonance relaxation tomography. Journal of Appl. Physics, 90: 1155-1163, 2001. G. C. Borgia, V. Bortolotti, P. Fantazzini. Mag- netic Resonance Relaxation-Tomography to Assess Fractures Induced in Vugular Carbonate Cores. SPE paper 56787, Proceedings of the 74-th Annual Technical Conference and Exhi- bition of SPE, Houston, 3-6 Oct. 1999. G. C. Borgia, V. Bortolotti, P. Dattilo, P. Fan- tazzini, G. Maddinelli. Quantitative determi- nation of porosity: a local assessment by NMR Imaging techniques. Magn. Res. Imaging, 14: 919-921, 1996.

U. Bilardo, G. C. Borgia, V. Bortolotti, P. Fan- tazzini, E. Mesini. Magnetic resonance lifetimes as a bridge between transport and structural properties of natural porous media. J. Pet. Sc. and Eng., 5: 273-283, 1991. CONTACTS [email protected] [email protected] [email protected] [email protected] www.mrpm.org

ADVANCED METHODS FOR CHARACTERIZATION OF ROCK MATERIALS AND