Psalm 16

As I read through this psalm, the first thing that strikes me is that David, the psalmist, asks God to keep hims safe and states God is his refuge. As you read further on in the psalm though, there is not much written about fearful thing. He states in v. 5 that his "lot is secure". So I am pondering what he means by refuge. The word in greek can also have the meaning 'to confide in' and perhaps that is more what his happening in this psalm.
From v 5-11 I see five examples of God's character and actions toward His own: v5-6 is God's sovereignty and protection; v7 is God's wisdom; v8 is God's security; v9 is God's promise and v11 is God's revelation.
What do you all think?