Study on the Influence of Heterogeneity of Low-Permeability Reservoirs on Wormhole Morphology and Acidizing Process Parameters

Abstract

Carbonate rocks typically exhibit strong heterogeneity, which can have a significant impact on the effectiveness of acidification processes. This article developed a non-homogeneous reservoir acidification process program based on the TSC model and open-source software FMOT, and studied the influence of heterogeneity intensity on wormhole morphology and acidizing process parameters. The results indicate that different heterogeneity intensities can produce different wormhole development patterns and wormhole morphology. In the early stage of acidizing, there is competitive development at low heterogeneity intensities and a transition to dominant wormhole development as the intensity increases. The differences in the wormholes morphology are mainly reflected in the branching wormholes. Low intensity forms fewer and wider branches, while high intensity forms more and narrower branches. As the heterogeneity intensity increases, the curve shows a downward trajectory characterized by a progressively diminishing rate of decline. However, this enhanced heterogeneity does not affect the optimal injection rate. The optimal injection rate increases with the increase in the acid injection temperature. Under high-heterogeneity conditions, the optimal injection rate increases more significantly with the increase in the inject temperature. Additionally, although typically there are increases with the rise in the inject temperature, this trend reverses under high injection rates.