Additional to OpendTect you may want to purchase commercial plugins. OpendTect uses FlexLM licensing for commercial plugins.
The FlexLM licensing system is expained below
FlexLM licensing
FlexLM (by Macrovision) is a well known licensing system used throughout the industry, and in the oil industry in particular. To be able to effectively manage licenses, every computer has a unique host identification . More information on this and other FlexLM issues: