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That allows diagnosing the various behaviour types on a p vs q plot of any well field data:
Fig. 4.C.11 – Field example P vs Q plot
Then, the adequate subset of points can be selected to be used in the corresponding methods.
It also allows comparing the behaviours from wells to wells in order to detect a possible
compartmentalization: if the plot exhibits two different slopes in the P.S.S., that tends to
demonstrate that they are depleting two different compartments.
4.C.6
History plot
For complex cases and noisy data where no specific behavior is seen on these diagnostic plots,
the linear plot of pressure and rates vs. time becomes the main tool. There is no real
diagnostic, just an optimization process. Under these conditions, it is not realistic to expect to
estimate more than a productivity index, mobility and a drainage area. In the absence of any
other information, the simplest analytical solution, homogeneous circular reservoir, will usually
be suitable to model the well drainage area. The use of more complex models can be
acceptable if complementary information is available from other sources, and the number of
parameters allowed to change in the optimization process is reduced to a minimum.
Fig. 4.C.12 – Production history match