There is no single oil market: a sourced EROI framework for middle-distillate (C12–C18) fuels

This note assembles a fully sourced, auditable EROI (energy return on investment) chain specifically for middle-distillate fuel — kerosene and diesel/gasoil, the ~C11–C20 boiling range — delivered to the point of use, and shows that the figure differs sharply, and for structural physical reasons, across both crude grade and consuming region. Two independent axes of differentiation are quantified from primary sources: (1) native middle-distillate yield by crude assay, which peaks in the medium-API-gravity band and falls at both the light and heavy extremes rather than scaling linearly with density; and (2) delivered energy return, built as extraction plus refining plus transport burden using a peer-reviewed refinery-efficiency regression (Elgowainy et al. 2014, 43 US refineries) and two independently published, self-consistent well-to-tank chains (JEC/Concawe for the EU crude supply mix; Cai et al. 2015 for Canadian oil-sands-to-US-Gulf-Coast pathways). Four supply chains are compared on a single, directly comparable basis: US domestic conventional crude (5.4:1), the EU's actual crude supply mix (3.8:1, a single self-consistent source), Canada-to-US diluted bitumen (2.85:1), and Canada-to-US pre-upgraded synthetic crude oil including the upgrading energy cost (2.0:1). The results show that the United States — simultaneously the world's largest light-crude producer and structurally dependent on imported heavy crude for its diesel pool — cannot substitute domestic shale output for the heavy sour barrels its Gulf Coast refining capacity was built to run; that pre-upgrading heavy crude before shipment is a net energy loss compared with shipping diluted bitumen to existing deep-conversion refining capacity; and that documented crude-grade splits (e.g. Iraq's Basrah export stream) are direct market evidence of ongoing field-quality decline. Every reported figure is provenance-tagged and traceable to a named, dated primary source; no term is filled with an unsourced estimate. The note explicitly distinguishes this delivered, middle-distillate-specific metric from broader societal or civilizational EROI — which includes natural gas, nuclear, and hydro and is outside its scope. This is a companion methodology note to EnergyIntellect (DOI: 10.5281/zenodo.21381857), the author's supply-side physical shock price-impact model for the global oil market.