Are there any standard regulations for oral exams for universities in Bologna process?
I don't believe there are any Bologna-wide regulations regarding the conduct of oral exams.

In general, the Bologna process is designed to set up the means of making education "portable," not strictly uniform. Individual countries and schools are given wide latitude for how they internally implement the processes: for instance, just look at the wide of grading systems used throughout the EU. 

As a counterexample to your question, I worked as a faculty member in Germany, and the rules varied between faculties, let alone universities. For instance, one or two professors could conduct the oral exam, notes were taken by a recorder, and the exam was rarely, if ever, recorded. The only situation where things got more complicated is if a person could fail out of the program by failing the oral exam, in which case having two professors, one of whom did not teach the subject, was required.