HOUSTON, Oct 15 (Reuters) - Rigs drilling beneath the deep waters of the Gulf of Mexico will drive U.S. oil industry growth this year and next as onshore production slows due to lower prices and maturing shale fields, and analysts and consultants expect the trend to continue as new technology and friendly regulations attract investment offshore.

The offshore oil and gas sector took a backseat to shale in recent years because drilling at sea requires years of construction work and higher upfront investments. Entry costs were lower for shale production and returns quicker, so rapid expansion in shale made the U.S. the world's top oil producer.

Now, technological improvements allow for high-pressure offshore drilling while U.S. President Donald Trump has brought in industry-friendly regulations. With the most prolific shale areas depleting in giant fields like the Permian, shale producers must shift drilling to less productive areas at higher prices.