I would imagine deep water drilling is a lot more expensive, hazardous, and disaster-risky than fracking is anyway. And fracking seems to be the wave of the future.
Hydraulic Fracturing is done offshore as well, but not as commonly as in onshore tight formations like shale.
Deep Water Drilling is expensive, and also has a very long time frame. It can be 10 years from when a company starts investing in a offshore field before it sees any cash flow from production. That makes it tough if the price of oil cuts in half from when you begin fabrication and when you flow oil.
Fracking ‘A’ buddy!!!