President’s Column – July 2007

Title: Drafted and Computed

Author: Jewel Wellborn

Publication: The Outcrop, July 2007, p. 3, 8

I find that in much of my work I often encounter two extremes: geologists who only use computers to construct their maps, and those who “wouldn’t touch one of those things” if their jobs depended on it! I started my mapping career with paper and color-erase pencils, a drafting staff to make the maps “look” good, and rolls of sepia to provide the “layers” I needed to visualize. Most geologists had a drafting table, some geologists even had a light table (I still do), and if you were really clever you had one of those electric erasers AND an electric pencil sharpener!

Today, you will likely find the geologist working on a computer, and if they are really lucky, they will have one of those old fashioned drafting tables near them … probably in a team work room. Most will have a “nearly” paperless office, with logs, rasters, and base maps completely encased in their computer software programs.

Although we may believe the best map is the hand-­drawn one, we often find the flexibility and time efficiency of the available mapping software can assist us in manipulation and creation of our maps. But… no matter what software you use, you must remember that computers are MATH machines, they are NOT Geologists. The computer does not think in true three-dimension, it does not know where the sand body is located or whether you would expect to find it parallel to the shoreline or in a channel. The computer operates totally on mathematics, with trends and projections–but it does not and cannot do the geology.

Probably the best geologic map is the one you drew as you walked the outcrop — you could see the features, make your notes, take your strike and dip, and measure the sections (do we still do this??). If you have done a significant amount of field work, you were trained to see in 3D as you observed the outcrops, visualized the data you collected, and recognized what the surfaces look like. There is nothing quite like being in the field with your boots on the ground. If you have had field experience, those experiences really help to “see” the geology that we attempt to re-create on a map — whether on a computer or on a drafting table.

However, with the computer, it is a bit harder — and the computer does not help unless you follow the rules of geology. You will need to know how to contour, how to pick the faults, correct for throw, verify the structural compatibility across faults, understand the geometry of the surfaces, validate how the surfaces connect and intersect one another (i.e. faults and structural surfaces), and oversee many more geologic parameters that are taken into account to construct an accurate map. Computers help us manage volumes of data, see it with a click of a mouse, post the data quickly, and construct various grids that we can then manipulate to represent our geologic concepts. But we still need to do the “geology.”

Some geologists have never hand-drawn a contour map; I know that is a surprise, but some have only worked on the computer. Those of us who have experienced the “other side” have some tricks that we may need to share in contouring and picking faults. When I came out of college I had at least four “mentors” who taught me some of their tricks –with pencils, and rulers, and plenty of erasers! There is still a need to provide mentors to those who are new to the industry. Geologists coming out of school are very computer-savvy, but may not have the geologic training or mapping experience to manipulate the software to bring geologic mapping concepts to bear on their maps.

I still see the need to spend time really looking at my computer drawn maps — and most times I do not have the time to sit, reflect, and let the maps talk back to me. My maps used to hang on the wall, and they pointed me in the directions I should look for opportunity. The cross-sections revealed the correlations while I stared at them (sometimes for hours) and many times I found the trends that I had drawn were like red arrows pointing to where the wells should be drilled!

So take some time — even on the computer — to let the maps “speak” to you. I call it “Soak Time.” Take the time to absorb the flow of the contours, the trends that are present, the boundaries, and then make your changes to your maps to engage the geologic concepts that you believe are in force. You are the master of the universe when you are creating your prospect maps and sections — and this is a powerful force in the art of our science.