He worked for many years as a geophysicist in the industry: from 1952 until 1962 at Mobil Oil A.G. in Celle, then until 1975 at Prakla-Seismos in Hannover, and finally until 1980 at Royal Dutch Shell in The Hague, Netherlands.

With his mathematical approach to solve problems of exploration geophysics, Bortfeld has had long lasting impact, in particular on the field of reflection seismology.

He is primarily known for the Bortfeld approximation[4][5] of the Zöppritz equations, which facilitated a physical interpretation of the reflection coefficients of seismic waves.

He has been considered as the father of the amplitude versus offset method,[1] which, after further developments, has played a crucial role for the detection of economically useful geological deposits.

During his tenure at the Clausthal University of Technology, he was in charge of processing the data for the German continental seismic reflection program (DEKORP).