Working in the County Overview

When you start an exercise, you will be presented with the County Overview window, containing a map of Small County showing the locations of towns, roads, streams, and 15 pre-existing wells drilled by a company named KGS. KGS has provided you with the information on elevations of major stratigraphic horizons in its wells. Selecting one of the KGS wells (with a single click) will display the stratigraphic information for that well in the Well Outline View to the right:

The height of each interval in the Well Outline View is proportional to the observed thickness of that interval in the selected well. The numbers shown to the right of each interval name is the elevation of the interval top, in feet above sea level. Negative numbers indicate tops that are below sea level. Ground surface elevation in Small County is around 2000 feet above sea level. More information about the stratigraphy of Small County can be found here.

The options in the Overlays menu at the upper right can assist you in navigating the the county. For example, here is how map looks if you turn on the township (blue), section (red), quarter-section (gray) grids:

In the exercise, you are only allowed to place wells in quarter-sections that are not occupied by towns, streams and lakes, roads, and previously drilled wells. More information about townships, sections, and quarters can be found here.

Your primary task in the exercise is to drill wells that are promising targets for oil production. As explained here, you are most likely to find oil in the Quivira Dolomite, Westport Limestone, Morn Sandstone, and Sawyer Sandstone, particularly where the tops of these formations show anticlinal or dome-like structures. You can display contour maps of the top elevations or thicknesses of various intervals using the Interval Property menu. Here a contour map of the elevation of the top of the Quivira Dolomite is displayed:

As explained in the discussion of contour maps, these maps only show estimates of the elevations and thicknesses, interpolated from the small number of observations at wells. The interpolated estimates become increasingly unreliable with increasing distance from the nearest well. When maps are interpolated from limited data, as here, they have a strong tendency to show "bulls-eyes" at the wells as an artifact of the interpolation process. Unfortunately, positive bulls-eyes can look a great deal like anticlines, so it is important to keep this shortcoming in mind.

Continuing with our example, let's say that you have chosen drill somewhere near the top of the apparent anticline in the northwestern part of the county, between two westernmost KGS wells, where the top of the Quivira Dolomite should be somewhere between 650 and 700 feet above sea level. Click on the Site Well button on the upper right to activate the well siting tool, then click on the location where you want to site the well (keeping in mind that you will not be able to drill through the stream or in the same quarter as the existing wells). Once you have selected the location for your well, you will be presented with an Intent to Drill dialog box like this one:

The dialog box displays prognosis information for the proposed well, including the would-be well name (from your company name and the landowner's name), the location in legal coordinates, the elevations of the ground surface and kelly bushing (KB), in feet above sea level, and the expected depths (feet below KB) and elevations (feet above sea level) of the interval tops at the proposed well location. The expected depths and elevations are estimated (interpolated) from the information at surrounding wells. Note that the estimated elevation for the Quivira Dolomite is within the expected range. After reviewing the prognosis information you may choose to go ahead with drilling by clicking Drill Well or you may choose not to by clicking Cancel. If you choose to proceed with drlling, you will see a dialog box saying that the well is being drilled and then you will be transferred to the Well Log View to work on interpreting the data from the newly drilled well.