A week's time is considered long for high risk hyips like that one. Knowing that the minimum rate tay pay is 5% it's quite easy to understand that why it can't stand for long. HYIPs today pay people from other peoples deposits. There rarely is some real profit generated. Seeing that oilrigconstructors is 29 days old today their 30 day big plan cycles tomorrow. It would be a big milestone if they make it past that point but I would be extremely cautious after this.
TL;DR I would consider every deposit into their website after today extremely risky. Don't invest what you can't afford to lose and be careful!
I agree that with their rates they won't last long, but I don't think hitting day 30 is gonna matter. I really doubt anybody put large deposits down for a 30 day plan on the first day of a HYIP with crazy interest. Plus the daily plans gives way higher returns than the month long plans anyways.