Transocean $RIG - Merging with Valaris

I've been watching this stock for a while now. They are an offshore oil rig contractor and have a very undervalued ticker compared to competitors... which was one of my first eye catchers. Today they announced a 6 billion dollar deal to acquire Valaris, which is another oil rig contractor... Valaris is valued at 83$ (30% surge today) a share while Transocean is just below 6 dollars. RIG tanked after the Deepwater Horizion ordeal and has yet to make a comeback since 2010... sad movie btw :(. I have never used merger news to make investment decisions which is why im making this post and would like some feedback. The merge deal would be a total stock deal and current shareholders of VAL would receive about 15 shares of RIG per share of VAL. Also, why would VAL soar 30% today if it will soon be delisted? Does this mean people are anticipating a surge in RIG's value.