Just follow the money train, along with supply and demand.  Big strikes on shallow oil and gas wells are a thing of the past.  As the demand increases, more production is also needed.  It take huge amounts of dollars and material to go deeper and farther for increased production.  New oil and gas wells cost in the millions of dollars to drill and bring into production.  New offshore wells take 18 months to 3 years to bring into production.

New, more restrictive regulations compound that cost.  Out of more than a dozen US steel mills, which make the items necessary for oil and gas production...only a small handful are left.  Most have gone overseas...which also compounds the cost.

US crude oil is a better grade of oil than the crap drilled in the MidEast.  It takes less refining.  It also is worth more.  The majority of US crude is shipped overseas for a huge profit.  The heavy black crude from the MidEast is imported here, which requires more refining, which creates jobs and drives up the cost.  US refineries are at capacity, more refineries are needed.  At the present time, the US uses the majority of the world's oil supply.  We do not have the production necessary to replace the foreign oil which we import.

You get the picture...