Is there a owned portal list available?

No, there's no way to get such a list, at least without cheating or without writing it down by hand. Also a list of that kind would probably help you very little: Ingress is a highly dynamic game, with control of the portals switching sometimes in the span of minutes.

Your goal should be to make sure you have the keys you need, regardless of you owning the portal. If you don't have its corresponding key, the fist hack has a high chance (almost 100%) to give you a key. Whenever a portal you own is attacked, you'll be notified, giving you the chance to fight back in some way. In this situation a list of your portals will give you no advantage, since tapping on the notifcation in the log will get you to the Remote View of the specific portal that is being attacked.

If instead you need this list to make plans, you'll have to arm yourself with a lot of patience and write it down on your own. I can assure you that when you get a little more experience, you'll know everytime which portals you are controlling, at least those that really matter to you.

With the number of players who have joined since Ingress left beta, the cmost useful tactic now is to pick a territory you can personally manage on a day to day basis (unless you are out in the sticks somewhere I guess) and focus on them.

When travelling in other areas simply upgrade/recharge/hack or destroy as needed. Don't worry about what keys you have for areas outside your remit unless they are strategic keys (eg for cross-ocean links, or hard to reach portals)

I currently have 40-ish in my local management region (which I charge daily), another 200 for the two nearest cities (which I occasionally link if I'm passing through), and then another 50 strategic ones (which I keep charged if others don't - in order to have them available for long distance links)

That's a pretty easy number to manage.