So if you're an oil company:
A lease must be obtained to explore for oil and gas using geophysical technologies such as reflection and refraction seismic, magnetic surveys, geologic surveys, etc. Once a location is deemed as having potential, a permit must be obtained, if not already included in the exploration lease, to do exploratory drilling. Drilling can cost millions, so you don't want to drill a dry hole. If oil is found, then you can obtain another permit to build a production facility to pump out the oil.
Now, the United States has already seen extensive onshore exploration and the big easy oil fields have already been found. The millions of acres of leases Nancy Pelosi and other Democrats talk about are for small pockets of possible oil that dot the landscape. This is risky because your chances of drilling lots of dry wells looking for the oil is high. Spending all that money is not attractive to oil businesses big or small, especially with no guarantee of a good return. Offshore is a different story. Much of it remains unexplored as the government currently will not give permits or leases for anyone to explore for oil and gas offshore since the ban, not to mention drilling. There are some big finds offshore that were found back in the heyday of oil exploration, but technology did not allow for deep water drilling.