It's a marketing deal. Use up theirs, and then rape them for ours.
Back before OPEC drove the price of oil down, we were an exporter. Now, not so much.
Oil prices were high. We found out how to extract oil from shale in the northern states and Canada. Expensive to produce and in Canada, when the tundra froze, it was impossible to drill, so it was somewhat seasonal. But, a lot of money was going into South Dakota and surrounding areas. Entire cities were being built and small communities were becoming rich.
Oil prices are a world wide business, still driven by OPEC. They control the markets with their oil and our shale oil is too expensive to produce to compete with them. They know this and are currently keeping the oil prices where they want them to keep their production high, and us relying on their production for gas and diesel.
I worked for 15 years at a business that built drill bits for drilling oil. My wife just retired from there in December of last year after 46 years.
We have a pretty good handle of how oil things are doing because of sales. Sales within the regions of producers also dictated the market.
Saudi and the other middle east countries punch holes with 28" drill bits that basically fall through the sand into the levels of oil bearing strata.
In the US, a 9 7/8' drill bit is the king. Just about everybody drilling uses that bit. Some with teeth hardened with stoodite like plow shares use, or some use carbide inserts for use in hard rock.
There are dozens of variations in the drilling industry and it all depends on the earth's structure they are trying to drill.
Sorry about being so long winded, but that's the state of the oil business in MHO.
