Checked out ROP website, if your whole trip is on Thai it will get you nearer 14,000 miles, but, no miles if V/W booking class.(from 1st June).
ROP ''Silver'' requires only 10,000 miles, so your one trip would instantly get you silver status plus you would get 3,000 threshold bonus miles as well.
Go to www.thaiair.com and the link for ROP, you can enroll online. Asks if ROP member recommended, send me a private message if you want to use my number.