Application of Levy random fractal simulation techniques in modeling reservoir mechanisms in the Kuparuk River Field, North Slope, Alaska

Incorporating a suitable level of heterogeneity into reservoir simulations is necessary for accurate prediction of production rates and final recoveri es. Spatial correlation of petrophysical properties, particularly permeabil ity extrema, exerts a profound influence on Row underlying reservoir displa cement and depletion processes. Common modeling techniques are founded on G aussian assumptions for statistical distributions. Such Gaussian-based appr oaches can inadequately model the permeability extrema that can dominate re servoir performance. However, optimal reservoir management strategies at th e Kuparuk River Field require that significant efforts be made to correctly model reservoir behavior. This study utilizes a new method, Levy fractal simulation, for interpolatin g permeability at a former gas injection area now being targeted for oil pr oduction. The main producing interval is a diagenetically and mineralogical ly complex elastic unit. The diagenetic complexity causes difficulties in t he lateral modeling of large changes in petrophysical properties observed i n near-vertical wells, particularly permeability. Prior efforts at modeling the movement of gas, at typical interwell scales, have met with limited su ccess. In this study, the Levy technique employs automatic calibration with lot: and core data for the interwell interpolation of the spatially comple x reservoir properties. The Levy fractal simulations preserve the sharp jum ps in reservoir properties observed at stratigraphic boundaries and within reservoir subzones. The spatially correlated petrophysical properties are c onsistent with geologic experience. A fine-scale permeability model incorporating well conditioning data was bu ilt using the Levy fractal interpolation technique. This model encompassed not only the gas injection area but drillsite patterns immediately adjacent . The model preserves the geometry of the reservoir units so that truncatio n and onlap relationships are preserved. The permeability extrema in the mo del are characterized by lateral continuities extending over many grid-bloc ks away from control locations. Porosity was modeled using sequential Gauss ian simulation in which well porosity logs were used as the primary conditi oning data, and the modeled permeability used as secondary conditioning dat a. The fine-scale model was then used as input in an upscaled dynamic simul ator built to test reservoir mechanisms. The model was also useful for prog nosing porosity and permeability at proposed well locations. Early drillin g results indicate that substantial quantities of producible oil remain in the former gas injection area.