Análise comparativa de métodos de avaliação do cone de água em poços de óleo verticais

Abstract

Water coning is one of the serious problems that can happen in the oil production of a vertical well. This study presents how the water coning is formed and the forces evolved in the generation process. It presents equations that forecast the water coning and it determines the considerations and limitations of each one. It presents breakthrough time and water cut equations. Using Excel sheets and Visual Basic for Applications (VBA), it analyzes the equations at different situations, while it varies important parameters of the petroleum reservoir and compare them to each other. It shows considerable differences at the results of critical rate and the results do not always behave as the expected depending on the situation. The critical rate correlations do not show a satisfactory reliability to be used in real cases and it is not easy to identify which equation is more appropriate. Therefore, specific simulations to each well or reservoir are the most exact solutions. The breakthrough time results are feasible, with minor differences between them. The water cut results are verisimilar, but there are not enough models to a better comparison.