Analytical and Statistical Interwell Connectivity Analysis in Tight and Complex Reservoir

Abstract

One of the most important parameters governing waterflood performance is connectivity between producer(s) and injector(s). Several methods have been established to infer interwell connectivity but as all methods have their own limitations, the best practice is always to perform an integrated analysis by applying several methods and comparing their results. This is especially important for tight and complex reservoirs like the TK reservoir highlighted in this study. The methodology implemented in this study was organized into four parts. First, the reservoir of interest was segmented into two and five regions by considering their statics and dynamics characteristics. Next, statistical method with Spearman’s correlation was applied to determine the connection between injection and production in each region. Subsequently, streamline simulations were performed to obtain a quick determination of producer/injector connectivity in each region. After inferring the connectivity between producer(s) and injector(s), their actual interactions were validated using production/injection analysis. The input data needed are production/injection data as well as simple geological characteristics. The workflow was performed successfully. Spearman correlation with a time gap quantified the degree of interaction between production and injection both for the entire reservoir as well as for each region. The streamline simulation enabled quick production/injection correlation between several producers and injectors at once. Results from these tools were then compared to results obtained from well-by-well production/injection analysis. Good agreement between the three methods were obtained thereby increasing confidence regarding the reservoir heterogeneity and interwell communication. This methodology provides rapid and easy techniques to obtain a more reliable reservoir heterogeneity characterization and quick identification of interwell connectivity which will be very important input for reservoir management and waterflood optimization. The proposed workflow can be deployed to other complex reservoirs.