Biography Citation for SEG Honorary Membership
Contributed by Peter Hubral
How does one distinguish a geologist and geophysicist from a geodesist? The simplistic definition still appeals to me that a geologist is a person who measures time in millions of years and a geophysicist measures it in milliseconds. Then, surely, if a geodesist would be asked to measure time (rather than the topography of the earth's surface) he would certainly want to measure it in nanoseconds (with a standard error deviation of 10-12 s).
Well, Johann (Hans) Sattlegger started off as a geodesist in 1957 with an honorable doctorate from Austria's Graz Technical University. However, after field work in Syria, he must have realized how attractive life can be for a geophysicist because he decided to become one. He worked from 1958 to 1973 for Deilmann Bergbau (in Germany) and Texas Instruments (in Houston) before founding his own company in Germany.
At the beginning of his career he obviously had a vision that one seismic service product time-depth map migration would always remain in great demand in both exploration and reservoir characterization. And right he was. He has devoted his research, throughout his career, to the development of this product and it has reached such perfection that, nowadays, if one talks anywhere in the world about map migration, one automatically talks about Sattlegger, and vice versa.
Indeed, with hindsight it seems obvious that no other subject in our field could have been more closely related to his geodetic background and his desire for high-precision measurements of surfaces. But who, decades ago, would have thought that map migration (in spite of the development of sophisticated 3-D wave equation prestack migration, etc.) would remain such a strong, solid island in the stormy sea of exploration and reservoir geophysics? Although that stormy sea did swamp many other companies of similar size, Sattlegger's firm became a stable and pivotal element in our industry an element his customers obviously feel very secure with and which they rely upon strongly.
There is, of course, a big difference between determining the topography of the earth's surface and that of seismic subsurface-target reflectors. The latter require, in addition to time-to-depth mapping, such procedures as mis-tie and velocity analysis, traveltime picking, 3-D velocity model building, fault definition, error estimation, reservoir volumetrics, integration of well information, etc. Hans has published some very fundamental papers about all of these techniques and, in fact, has brought them to the utmost precision (for which he received EAEG's Conrad Schlumberger Award).
The numerical codes on his programs, now installed at 30 client locations around the world, are exclusively his own brainwork. He informs me that 80 percent of the development of his programs is nowadays customer-driven. Is this the secret of his success?
But you are wrong if you think Hans has moved away from science to business and now devotes all his attention to his clients' interests. You can usually find him, at EAEG and SEG conventions, at his booth. Go and talk to him. You will like his Austrian charm and you will be surprised how up-to-date he is in any technical or scientific topic.
Hans now lives in the German lowlands, a totally different environment from his Austrian homeland (where, though, you can still meet him on the ski slopes in winter). We German geophysicists are happy that he chose our country in which to establish his successful company. Not only has he helped give our applied geophysical research a good international reputation, but he has also employed and mentored many of the finest German geophysicists. We are pleased, like all his friends and clients, to see that Hans has received one more well-deserved award.