indicates that injection to each well has a positive impact on the
ultimate recovery of oil but as is evident in Fig. 4, injection to
well#2 has the greatest impact on the oil production whereas injection
to well#4 has minimal impact. By the way, influence of gas
injection to wells 3, 5 and 1 is intermediate between wells 2 and 4.
Therefore this method can successfully determine the well which
has the highest value in gas lift operation.