When working with large numbers of wells we often don’t have a fully picked stratigraphic framework available. This can cause issues when you are trying to perform calculations using defined zones. There are two options available to the user in this case:
- Pick out the tops manually
- Use automation to fill in the missing tops
Picking the tops manually, even though it is quite easy in Danomics, can still take a substantial amount of time if there are 1000s of wells and several horizons. For projects with short timelines this means we have to use some sort of automated method. In the simplest case we will use structural grids made from existing tops datasets to define tops in wells where they are not currently present. To do this we will use the TopsInterpolation flow.
Before starting it is important to understand how this works. The system we will be using does the following:
- Reads in your existing tops
- Generates a structural grid for each top
- Reads in the depth curve from the well log
- Determines if there is an intersection between the wellbore and the structural grid
- Applies the logic that IF a top is already present, keep original, IF NOT present and wellbore and grid intersect, add new top. If wellbore and grid do not intersect, skip.
This means that once you run it, every well should have the tops that would be present in the well if manually picked. Note, the accuracy of this depends on the quality of the initially picked tops and the subsequently generated grids. It is important to QC preliminary grids (just make a structure map in the petrophysics file) to ensure that they look reasonable.
Tops Interpolation Flow
We accomplish the tops infilling via a flow as shown below:
Start, by selecting your relevant log database in the LogInput block. Next, in the PointsInput block select your tops database.
In the TopsInterp block you will need to set the log dataset and the well headers database that covers the wells of interest.
And finally, in the TopsOutput block you will need to provide a name for the resulting tops dataset.
Once you have ran this, you can then use the Interpolated Tops in your petrophysics projects!