A Proposed Cone Breakthrough Time Model for Horizontal Wells in Thin Oil Rim Reservoirs

Abstract

Abstract Understanding oil rim reservoir production dynamics is critical to successful development of thin oil rims. The interplay of subsurface factors and production constraints determine the dynamics of oil Rim reservoir production. Therefore in this study the impact of a range of sub-surface uncertainty on oil rim recovery was captured by employing the Plackett-Burman Design of Experiment (DOE) technique. The methodology involves a detailed generic oil rim simulation study. By employing the classical numerical reservoir simulation equation, assuming a negligible difference in fluid potential and applying material balance principle, the response surface model or proxy developed for cumulative oil recovery (Np) was combined with the cone breakthrough time equation and forms an integral part of the model. The model was developed for a thin oil column, between 20ft-60ft, sandwiched between a gas cap and aquifer. The results from the model were compared with that gotten from a simulation study which gave reasonable value of cone breakthrough time with its equivalent water cut value. The applicability of the model was tested by predicting the water breakthrough time for some selected major oil rim reservoir with gas cap and Aquifer in Niger-Delta. The proposed model is reliable based on the fact that it captured some major sub-surface uncertainties (11 sub-surface parameters) that influences coning results while most pre-existing model do not. It can as well serve as a quick predictive tool before embarking on detailed reservoir simulation.