Diagnostic Plots for Analysis of Water Production and Reservoir Performance (A Case Study)
The research is aimed at the understanding of the various diagnostic plots for the analysis of water production that are available as well as the application of these methods in a case study. It also aimed at the establishment of a work flow for the evaluation of water production mechanisms. A workflow was developed that combines numerical simulation and diagnostic plots to analyze the water production performance in a reservoir. This workflow was validated using a case study. The multi-layer reservoir model with varying vertical permeability was constructed using a numerical simulator with the reservoir properties of the case study. Trends from the field data were analyzed using the trends observed from the simulated data as templates. For the production wells, oil rate and water rate versus time plots as well as the X-plot were used to evaluate water production characteristics of the case study. The water-oil ratio (WOR), WOR derivative and X-Plot were used for the field production diagnosis while the Hall and the Hearn Plots were used for the water injection well diagnosis. The results of the diagnostic plots showed that multi-layered channelling was the controlling mechanism and the cause of the water production in the case study. For the injection wells, the plots indicated that some wells in the case study had the problem of extensive near wellbore fracturing while other wells had the problem of wellbore plugging. The workflow and results of this study can be applied by reservoir and production engineering teams to other reservoirs to diagnose water production mechanisms; identify sources of water production, and provide information for planning water management programmes to mitigate excessive water production problems.