extraction location for petroleum based raw materials

I'm cross posting my question here, as it pertains to LEED v4 raw material sourcing, and in documenting regional materials, others may have encountered the same issue. I am working on documentation for the LEED v4 Raw Material Sourcing credit and need some advice. In order to document enough raw materials to comply with the final LEED v4 credit wording, some of the raw materials will be petroleum based. Oil is a global commodity. How far up the supply chain do I need to go to collect extraction location and commitment to environmental practices from the supplier? For example, our carpet uses a coating made from EVA, a copolymer. We can determine where the EVA was manufactured but it's not possible to determine where the ethylene and vinyl acetate were created.