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Compositional variation in hydrocarbon reservoirs with natural convection and diffusion
Author(s) -
Riley Mike F.,
Firoozabadi Abbas
Publication year - 1998
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690440221
Subject(s) - convection , natural convection , perturbation (astronomy) , temperature gradient , asymptote , thermodynamics , mechanics , chemistry , mathematics , physics , mathematical analysis , meteorology , quantum mechanics
Abstract The knowledge of horizontal compositional variation is of prime importance in hydrocarbon reservoir delineation. However, the effect of natural convection on this variation is largely unknown. This work examines the effect of natural convection and diffusion (thermal, pressure and Fickian) on a two‐component, single‐phase fluid occupying a horizontal cross‐sectional reservoir in the presence of a prescribed linear temperature field. The behavior is investigated using a method of successive approximations, which iterates on solution of Poisson's equation. This behavior is then incorporated in a simplified perturbation solution (in the form of a cubic equation) which not only gives accurate values of horizontal compositional variation, but also clearly shows the interplay of reservoir/fluid properties. The perturbation and the full solutions indicate that a small amount of convection can cause the horizontal composition gradients to increase until a maximum is reached and then decay as 1/k. An alternative scenario is that the gradient asymptotes to a value where the horizontal density derivative approaches zero. Generalization of this perturbative solution to n‐components apparently requires the simultaneous solution of n − 1 cubic equations.