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Dynamic Data Analysis – v5.12.01 - © KAPPA 1988-2017
Chapte
r 3 – P ressure Transient Analysis (PTA) -p117/743
Fig. 3.I.4 – QA/QC plot with difference
Fig. 3.I.5 – Match non drifting gauge,
no fault
Fig. 3.I.6 – Match drifting gauge, with fault
3.I.4
Phase redistribution
When different phases are produced the redistribution of fluids in the wellbore at shut-in may
be almost instantaneous and produce what is called ‘gas humping’. This may (seldom) be seen
in a water / oil case also. At shut-in the fluid mixture separates and a total reversal of fluids
occurs in the wellbore. The heavier fluid moves to the bottom of the well and the lighter fluid,
usually gas, accumulates at the top. This can produce a hump in the pressure at shut-in
sometimes above the reservoir pressure.
Only when the two phases are stabilized will the buildup return to a normal pressure difference
and the response may be analyzed.
1E-3
0.01
0.1
1
10
10
100
1E-3
0.01
0.1
1
10
10
100