This paper presents a case history of an integrated study of a mature carbonate waterflood located in Mexico. The objective of the study was to determine a redevelopment plan that optimized the remaining hydrocarbon recovery from the field. The field has been in operation for over 40 years. Most of the 343 wells in the field were drilled in the late 1950s and early 1960s. The field has been under waterflood operation since 1967.
This study integrated log analysis, geology and petrography, reservoir and production engineering, and numerical simulation. Because of the age of the field, this study presented some unique challenges. For example, the vintage of most of the open-hole log data required special analyses to determine porosity and water saturation.
We developed a custom PC-based relational database early in the project to manage the large volume of production and injection data and basic reservoir engineering data. This database was one of the most important components of the study because it allowed project team members to access the data easily and quickly.
The reservoir characterization resulted in a 21-layer geological model. We constructed a 3-dimensional, 3-phase numerical simulation model and calibrated it with over 40 years of primary and secondary recovery performance history from 273 wells. Because of the large amount of performance data to history match, we developed a special strategy for the history match of this reservoir's performance.
On the basis of the analysis of this reservoir, we determined that the production rate and remaining recovery could be increased significantly provided that an aggressive redevelopment plan is implemented. This redevelopment plan included reconditioning existing wells, converting wells to water injection and adding infill producers and injectors in the field. The results of this study demonstrate that the simulation model developed for this reservoir is an effective tool for the future management of the field.
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