I spent 50 years working in the petroleum industry in various positions for small and large companies. I found that the larger companies had more specific duties for "Landman". Some were doing duties involving title research and lease acquisition. Others dealt with Row and working with surveyors in staking well sites.
The "Landman" working for the smaller companies did it ALL; whatever it took from title research to final curative to get the well drilled and all documents necessary to get payment of royalties. Now, I say that is what a Landman is. Those in the courthouses running title to minerals only are mineral abstractors; a LANDMAN performs ALL of the other duties. PERIOD.