Changing Zone's Risk Grade and Updating Coverage

From the last section, we saw that the Main Gas Zone with the Default Grade with a gas cloud size of 10 meters resulted in 87.1% 1ooN and 34.3% 2ooN. The 5m Gas Cloud risk grade was set as the Visible risk grade. This section will change the risk grade of the Main Gas Zone and it will be seen that the 3D window will remain unchanged - opposite from the last section where coverage results were unchanged while the 3D window changed.


Select the Main Gas Zone in the Project Items Tab and change the Risk Grade to 7m Gas Cloud as shown below. After updating the risk grade the coverage results table will recalculate. Here the 1ooN coverage has lowered to 55.4%, this is expected because of the smaller gas cloud size.


Tutorial 6 - Figure 07 - Changing the associated risk grade of the zone which will affect the coverage as it has a different gas cloud size


Notice that the 3D window remained unchanged in this process because the Visible risk grade (indicated by the blue arrow below) did not change.



Tutorial 6 - Figure 08 - Indication of the updated coverage results when the associated risk grade was changed (red arrow) but the 3D window remained unchanged


Repeat the above and change the Risk Grade for Main Gas Zone to 5m Gas Cloud. Now the Visible risk grade matches the one assigned to the zone.



Tutorial 6 - Figure 09 - Updated Main Gas Zone with 5m Gas Cloud risk grade


It is recommended to keep the Visible risk grade the same as the risk grade assigned to the zone you are working with for your project. To avoid confusion, risk grades can be deleted so that only one risk grade is present in the project.