Aquifer Encroachment Exercise

The reservoir-characterization team has delineated a correlatable fault-bounded genetic unit. Now the aquifer encroachment needs to be interpreted and the team wants to test whether this genetic unit is acting as a flow unit. The production data are to be analyzed in order to answer these questions. First, a time-series analysis of water production is to be performed. The production rate vs. time graphs for oil rate and water cut are provided. Also provided on a map are subsea structure and depth of lowest water production. Use the map and graphs to complete the table below, and determine the timing of initial water breakthrough and the changes of water cut over time.

Look at the map to fill in Depth of Lowest Perforation and the five flow-unit history graphs (1, 2, 3, 4, 5) to add the Date of 1^st Production.

Now that you have completed the table, answer the following questions.

1. What is the order in time of water breakthrough for these wells?
2. Does structure affect the encroachment of water?
3. Should the reservoir characterization team consider this genetic unit a flow unit?
4. When well 329 was drilled and completed in June 1991 did it initially produce water-free?

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