GGU-SLUGTEST: Type curves after COOPER

A dialog box with the heading "Type curve generator after Cooper" opens.

First, you enter the "No. of Stehfest points". This correlates directly to the numerical method used for calculating the type curves. Generally, you should leave this at the 12 point default. In principle, however, the type curve would be more precise the higher the number of Stehfest model points. Nonetheless, because of the limited precision of your computer, the results may be rather strange for values above 18.

The number of Stehfest points must always be even.

Next, you enter the type curve parameter alpha. A useful range here is between 1e-1 and 1e-10, approximately. You can now enter the dimensionless start and end time for the type curve. A useful range for beta here is between 1e-4 und 1e+4. Finally, you are asked for the number of time steps per logarithmic decade. The default value is ten steps.

The higher the number of steps, the greater the number of data pairs included in the type curve. The computation time increases accordingly.

Once you have defined everything as you require, confirm your input with "OK", or abort the process with "Cancel".

When the program has concluded computations you are asked whether you want to save the type curve. If you answer this by pressing the "Yes" button a Windows dialog box opens where you can use "Save file as" to save the type curve. The program suggests ".tku" as the extension for the type curve file name.

If you have saved the type curves or replied to the previous question with "No", you will be asked whether the type curve should be included in the list of available curves. The program then stores the curve.

If you want the calculated type curves to be permanently saved, you must save them using "Type curves/Edit type curves" button "Save", as described in Section “"Edit type curves" menu item“. The default file is called "GGU-SLUGTEST.tkv".