Figure 2.  Type “A” graph illustrates a typical production decline curve of a depletion reservoir.  Type “B” production decline shows a secondary production increase resulting from infill drilling, recompletions, workovers and/or flooding.  Type “C” production curve shows the secondary production is higher than the initial production rate.  Type “D graph is typical of a rejuvenated marginal field.  Production increases are the result of operations similar to Type “B” and Type “C”.