‘Upstream’ is about extracting oil and natural gas from the ground; ‘midstream’ means transporting and storing the resources. ‘Downstream’ includes converting these resources into the finished products we all depend on. Oil, natural gas products are even used to make artificial limbs, hearing aids and flame-retardant clothing to protect firefighters. Together, these three sectors sustain the steady flow of fuels and materials that make life better and safer for us all. The term ‘upstream’ also includes the steps involved in the actual drilling and bringing oil and. natural gas resources to the surface.”]
Source: https://energyhq.com/2017/04/upstream-midstream-downstream-whats-the-difference/