Transport of Organic Components from Immobile and Bypassed Oil in Porous Media O. Huseby, A. Haugan, J. Sagen, and J. Muller Institutt for Energiteknikk, Kjeller, Norway B. Bennett and S. Larter NRG, Drummond Building, University of Newcastle, Newcastle upon Tyne, UK E. S. Kikkinides CPERI, Center for Research and Technology Hellas, Thessaloniki, Greece A. K. Stubos National Center for Scientific Research  Demokritos, Athens, Greece F. Yousefian and J.-F. Thovert Laboratoire de Combustion et de Detonique, Poitiers, France ´ P. M. Adler Institut de Physique du Globe de Paris, Paris, France An experimental study, as well as theoretical and numerical models, are used to ®alidate a methodology to exploit con®entional geochemical data with regard to the concentration profiles of organic components occurring naturally in hydrocarbon reser- ®oir oils. The experiment was designed to study transport of organic compounds from bypassed oil during water injection using a homogeneous oil-filled core sample, which was made heterogeneous by drilling a hole through its central axis and filling it with a highly permeable material. Under the present conditions, diffusion coefficients are the most important parameters controlling the transport, and the effect of partitioning could be accounted for by a simple normalization. The experimental results are well described by a simple 2-D analytical model that assumes instantaneous remo®al of solutes from the oil  water interface. The experimental results are also well described by two numeri - cal models, of which one is a full-featured reser®oir scale model, suitable for applica- tions of the methodology to reser®oir-scale cases. Introduction The task of estimating the presence and location of by- passed oil is highly relevant to tertiary oil recovery method- ologies. Such methodologies are expected to become more important as the discovery of new oil reserves starts to de- cline. In 1996, for example, about 3% of the world’s oil pro- duction and about 11% of the U.S. production came from Ž . Ž . enhanced oil recovery EOR projects Taber et al., 1997 . The obvious economic potential represented by undevel- oped oil in existing oil reservoirs is therefore an important Correspondence concerning this article should be addressed to O. Huseby. motivation for studies related to the estimation and produc- tion of bypassed oil. Undeveloped oil from bypassed regions in mature oil fields is discussed by, for example, Watters et Ž . Ž . Ž . al. 1999 , Montgomery et al. 1998 , and Walker 1997 . Ex- perimental studies of mass transfer from bypassed oil have Ž . been conducted by Le Romancer et al. 1994 , Burger et al. Ž . Ž . 1996 , and Burger and Mohanty 1997 . In addition to the relevance for oil production, the estima- tion of the presence and location of oil pools is also relevant in subsurface hydrology. Increasing attention has been de- voted to the estimation of the presence of nonaqueous phase Ž . liquids NAPLs and remediation of NAPL contaminated May 2003 Vol. 49, No. 5 AIChE Journal 1085