Curation rewards and not linked to reputation score. The important measure is your level of Steem Power.
A higher level of Steem Power gives you a larger upvote and a greater share of the curation rewards on a post.
However there are other elements which also affect the level of curation rewards you receive on a post:
- Early upvoters on posts that go on to make high post payout receive high curation rewards, the idea being that early upvoters are finding good posts and bringing them to the attention of other users.
- However upvotes made in the first 30 minutes return a proportion of the curation rewards to the author (the proportion decreases linearly over time from 0 to 30 minutes - this will also change with HF20).
[A fuller explanation can be found here:
https://steemit.com/curation/@miniature-tiger/an-illustrated-guide-to-curation-from-the-simple-to-the-complex-with-real-examples-from-past-posts-part-2]
In theory it is possible to obtain curation rewards even with only the initial 15SP, if you are really good at curation-seeking. In practice you will need around 50SP to consistently be receiving curation rewards and 100SP to receive curation rewards on pretty much all your posts.
That said, the curation rewards from 50-100SP are typically around 0.001-0.002SP so very, very low. It is much better to focus on commenting and writing posts if you are looking to build your SP.
It is also worth remembering that it takes 7 days for a post to reach payout and you will not receive any curation rewards before this point (none of your recent upvotes are older than 3 days).
Hope that helps!