Is it self-plagiarism to summarise a topic in the introduction of two of your papers using similar references and examples?
As you have stated, your papers have similarities and that the text is written separately and not copied, then no, this is not plagiarism (and is unlikely to be seen as such).  Using the same references is fine and necessary for similar concepts. 

It also sounds like the context between the two papers are distinct, this should ensure that the two papers are written differently.

Make sure you re-read and compare them to ensure that they are sufficiently different, which you sound like you have already done (and possibly ask a colleague to compare them). If possible and relevant, you could have one of your papers cite the other.

There are many guides about plagiarism and what to check for online, for example, this one from the University of Western Australia.