The Reginald Fessenden Medal
Contributed by Michael J. Sheen
Donald Howlett was the recipient of the Reginald Fessenden Medal in 1998.
It is with great respect and personal honor that I introduce a long-time colleague, Don Howlett, whom we are recognizing for his innovative work on the instantaneous floating point amplifier. This fundamental concept has facilitated the measurement of widely varying seismic signals, the foundation upon which the entire seismic industry is constructed.
I have known Don Howlett since our first association at Texaco in 1970. We spent seven productive years together adapting advances in electronic engineering to seismic instrumentation. Following my departure from Texaco, we continued to combine our many common interests in pursuit of this goal.
Don completed his academic training at the University of Arkansas where he received a degree in electrical engineering in 1962. His early endeavors in the application of electronics technologies led him to seismic exploration technologies at Texaco. As a summer intern in 1961, he was a member of the team that installed Texaco's first digital seismic field system into a truck. A few weeks after returning to Texaco in 1962, he was a student attending a three-month training class being taught by Bob Loofburrow on the new digital seismic recording system. Halfway through the course, Bob decided to turn over the teaching duties to Don. This was rather like teaching someone to swim by throwing him into the water.
Don must have found a strong personal interest in our industry's many challenges because his prolific innovations rapidly advanced the capabilities of Texaco and the seismic industry in general. I know we shared a "hands on" philosophy of constructing seismic recording solutions that utilized the increasing availability of sophisticated electronic components and technology. His many dedicated days, nights, weeks, and months, in the often hostile field and marine vessel locations, are obvious testimony to his determination to find solutions to the "seismic exploration challenge."
In the mid-1960s it became obvious that the emerging transistor and "flat-pack chip" technology could replace existing "tube-type" amplifiers in seismic instrumentation. This transistor technology moved rapidly to replace the unstable seismic recorders in use at that time.
However, these new solid state systems still required extensive operator intervention when applied to the seismic method. The operator was required to "predict" the decay in seismic signal amplitude with respect to time/depth and offset from the source location. This led to many operator errors and continued inefficiency in the field. Don envisioned a unique method to automatically record, scale the gain, and adjust the seismic amplifier on a sample-by-sample basis. He took what was previously a promising but seemingly impractical concept and developed it into a working field system which surpassed the performance of all previous instruments. This became known as the instantaneous floating point amplifier. Now for the first time the seismologist had the tools to accurately record the seismic data on tape in a manner which preserved the complete dynamic range. This door was opened for development of many of the sophisticated data processing algorithms that exist today.
In the late 1960s Don authored six of Texaco's 12 patents on the floating point amplifier system, and an additional patent using radio telemetry of seismic data (basically describing the OPSEIS system). In 1970 Texas Instruments began mass production of the DFS-RV EFP system using these concepts, under license from Texaco. The floating point amplifier became the industry's standard seismic recording method and remained so until the early 1990s when sigma delta technology was introduced.
Don holds 19 patents, with others filed but not yet issued. His work has led to many innovative methods of land and marine seismic exploration, and to seismic imaging within a producing wellbore. These methods are some of the tools that allow geoscientists to create seismic images of the reservoir which were never possible before. Don's determination to continue these improvements have aided in the identification of bypassed oil resources and improved oil recovery technologies, which we are all just beginning to understand.
Each of these concepts has benefited the seismic industry worldwide, and it is a true pleasure to participate in the acknowledgment of his efforts by writing this citation for the Reginald Fessenden Award.
We all hope that Don will continue these efforts for many more years; his leadership and guidance benefit all in the geophysical industry. As seismic equipment manufacturers, geoscientists, field technologists, and petroleum consumers worldwide, we thank Don Howlett for his creative achievements.