This paper summarises the results of a benchmark study that compares a number of mathematical and numerical models applied to specific problems in the context of carbon dioxide (CO 2 ) storage in geologic formations. The processes modelled comprise ad-H. Class (B) · A. Ebigbo · R. Helmig · M. Darcis · B. Flemisch vective multi-phase flow, compositional effects due to dissolution of CO 2 into the ambient brine and nonisothermal effects due to temperature gradients and the Joule-Thompson effect. The problems deal with leakage through a leaky well, methane recovery enhanced P. Audigane BRGM, French Geological Survey, 410 Comput Geosci (2009) 13:409-434 by CO 2 injection and a reservoir-scale injection scenario into a heterogeneous formation. We give a description of the benchmark problems then briefly introduce the participating codes and finally present and discuss the results of the benchmark study.

. TwoDimensional reactive transport modeling of CO2 injection in a saline aquifer at the Sleipner site, North sea. American journal of science, American Journal of Science, 2007Science, , 307, pp.974-1008Science, . <10.2475Science, /07.2007

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International audienceGeochemistry plays an important role when assessing the impact of CO2 storage. Due to the potential corrosive character of CO2, it might affect the chemical and physical properties of the wells, the reservoir and its surroundings and increase the environmental and financial risk of CO2 storage projects in deep geological structures. An overview of geochemical and solute transport modelling for CO2 storage purposes is given, its data requirements and gaps are highlighted, and its progress over the last 10 years is discussed. Four different application domains are identified: long-term integrity modelling, injectivity modelling, well integrity modelling and experimental modelling and their current state of the art is discussed. One of the major gaps remaining is the lack of basic thermodynamical and kinetic data at relevant temperature and pressure conditions for each of these four application domains. Real challenges are the coupled solute transport and geomechanical modelling, the modelling of impurities in the CO2 stream and pore-scale modelling applications

S U M M A RYWe propose an approach for estimating the permeability tensor using seismic emission induced by borehole hydraulic tests or by a £uid injection of an arbitrary nature. This approach provides a single estimation of the permeability tensor for the complete heterogeneous rock volume where the seismic emission was recorded. The approach is an extension of the method proposed by Shapiro et al. (1997) for the isotropic case. It is based on the hypothesis that the triggering front of the hydraulic-induced microseismicity propagates like a low-frequency second-type compressional Biot wave (corresponding to the process of pore-pressure relaxation) in an e¡ective homogeneous anisotropic poroelastic £uid-saturated medium. The permeability tensor of this e¡ective medium is the permeability tensor of the heterogeneous rock volume upscaled to the characteristic size of the seismically active region. We demonstrate the method using the microseismic data collected during the Hot Dry Rock Soultz-sous-Foreª ts experiment (Dyer et al. 1994). These data show that the corresponding rock volume is characterized by a signi¢cant permeability anisotropy caused by oriented crack systems. The maximal principal component of the permeability tensor has a subvertical orientation. It is about seven times larger than the minimal subhorizontal principal component.