I do not claim to know anything. I report on things I have read and I usually post websites to where what I read can be found.
I have posted about this topic previously and provided websites so I am just winging it off the top of my head here.
Supposedly the transition to using other sources of fuel in Mexico has already begun. How this will happen I have no idea.
Contracts have already been let and construction and refitting of old refineries has begun. Money has been paid to various different companies around the world who are contracted to do the upgrades to Mexico's refineries. They are bringing in international specialists who have built reduced pollution refineries around the world. Notices online clearly indicate this money has been paid.
Researching information for another forum topic about Hoy No Circula I also came across written laws about getting ULSD in Mexico and primarily Mexico City and other large cities in an attempt to reduce pollution. They know it must be done and they are working on it according to the articles I have read and posted website addresses here previously. The Hoy No Circula law I found talked more about cleaning up vehicles and inspecting vehicles and cleaning up the fuel supply than it did about who can drive what and where.
Research I have done on the internet has turned up no refinery in the US that still produces LSD fuel - all indications are that no US refinery continues to produce LSD - only ULSD is produced in the US - there is simply no economically feasible reason for US producers to produce anything but ULSD. If it comes from the US it will be ULSD.
I also posted about at least two pipelines from oil fields in the US that are being built to the Mexican border. What this means I do not know. I believe this would be crude oil but not sure. We saw the pipelines last winter near Van Horn, TX and inquired about them. One will run south from Van Horn and the other from Van Horn to El Paso and then south from there.
At least two major US oil exploration companies are already working in Mexico - Schlumberger and Halliburton - and there are probably others. It is my understanding that new wells are being drilled and new fields are opening up.
Things are changing but who knows where they are going. Who can keep up with it all....