Emeraude v2.60 – Doc v2.60.01 - © KAPPA 1988-2010
Guided Interpretation #6
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B06 - 12/13
B06.5 • Time lapse presentation
The ‘Time-Lapse’ option allows presenting together any number of successive saturation
curves, in order to visualize the variations of the saturation with time as new pulsed neutron
surveys are performed. In our example, the TDT survey that we just interpreted was
performed in 1982, and we want to compare the saturation with the original saturation
computed from open hole logs run in 1980.
In the browser:
Drop the original saturation from the ‘Down2’ onto the ‘Time-Lapse’ node.
Rename it ‘SW80’.
Click on the ‘Time-Lapse’ icon in the Control Panel.
This opens up a dialog box in which the applicable Sw curves are selected for the time-lapse
presentation. Of course it is essential that the earlier Sw profiles be selected first in order to
respect the timing sequence for the presentation. Failure to do this would result in an incorrect
shading sequence for the time-lapse presentation, yielding an incorrect visual representation of
the replacement of hydrocarbons by water.
The ‘Include SWCalc’ box in the ‘Interpretation settings’ was previously checked and although
SWCalc does not appear in the time lapse dialog nor in the time lapse node, it will
automatically show in the PVA view and will be considered as the most recent saturation.
Once the dialog box is closed, the PVA view will display BVW curves corresponding to the two
saturation profiles, SW80 and SW, Calculated. The deep-blue coding represents the original
water, and the light blue represents the produced hydrocarbons that have been replaced by
water. Green represents the hydrocarbons remaining after the 1982 TDT survey.
Two more surveys were performed over the interval 4520-4670, a TDT in 1990 and an RST in
1997.
Reduce the depth interval to the above limits, and load the SW90 and SW97 channels from
the B06_tl file using the load option in the ‘Time-Lapse’ dialog.
If necessary, declare the Mnemonics SW90 and Sw97 in ‘Water saturation’.
Skip the SW80 saturation already present in the ‘Time-Lapse’ node using the ‘Filter’ option.
The two saturations can be loaded simultaneously and will be displayed directly into the ‘Time-
Lapse’ node. The name affected to the loaded saturations is the name originally found in the
file (showing as the ‘File Mnemo’ in the loading dialog).
In order to respect the timing sequence of the surveys, SWCalc must show between the SW80
and SW90 saturations, which is not possible with the present choice of options.
Go to the ‘Interpretation settings’ dialog and uncheck the ‘Include SWCalc’ box.
Go back to the ‘Time Lapse’ dialog and click on the browser button.
That button accesses a ‘selective’ data browser showing only the relevant (already loaded or
calculated) Sw curves that can be chosen for inclusion in the time lapse interpretation.
Select the ‘SWCalc’ saturation and click OK.