Hello. My name is***** can help you with your question.
The calendars are not going to merge. What I would suggest doing is taking one of your Google calendars and making it the primary calendar on your phone or the other way around. That way you have one main calendar that you are using from both devices. The easiest way is to make it a public calendar in Google and then you can simply have your mobile device go out and grab that calendar whatever needs it and synchronize.