After two folds, the rope exceeds the well platform by 9 meters, that is, the remaining 9×2= 18 meters.

After being folded by 30%, the rope is 2m beyond the well platform, which means that the remaining 2× 3 = 6m.

The remaining 18-6 = 12m.

Therefore, the depth from the drilling platform to the water surface is 12m.

Rope length: 12× 2+9× 2 = 42m.