Cupiagua: A Complex Full-Field Fractured Reservoir Study Using Compositional Upscaling

Abstract

Abstract The first application of compositional upscaling to the routine modeling of a major reservoir is described. The reservoir, Cupiagua in Colombia, is a rich gas condensate field. Given that Cupiagua falls rapidly below dewpoint, and produced gas is recycled, the main recovery process is the vaporization of liquid components into the gas phase, and transport of these components in the gas phase to production wells. Therefore the process is compositional but flow is dominantly in 1 phase. Cupiagua is a heterogeneous reservoir, in which the main heterogeneity consists of natural fracture corridors, accounting for more than 80% of the permeability in some areas. It is not possible to represent these features explicitly within the full field model (FFM), nor do they fit a conventional dual porosity representation. Therefore an upscaling process is required. The process described in this paper is the use of alpha factor compositional upscaling functions, which modify the velocities of individual pseudo-components. Alpha factors are now incorporated into the Cupiagua FFM and are in daily use for all modeling applications in this major field.