Producing, transporting, and refining crude oil into fuels such as gasoline and diesel accounts for ∼15 to 40% of the “well-to-wheels” life-cycle greenhouse gas (GHG) emissions of transport fuels. Reducing emissions from petroleum production is of particular importance, as current transport fleets are almost entirely dependent on liquid petroleum products, and many uses of petroleum have limited prospects for near-term substitution (e.g., air travel). Better understanding of crude oil GHG emissions can help to quantify the benefits of alternative fuels and identify the most cost-effective opportunities for oil-sector emissions reductions. Yet, while regulations are beginning to address petroleum sector GHG emissions, and private investors are beginning to consider climate-related risk in oil investments, such efforts have generally struggled with methodological and data challenges. First, no single method exists for measuring the carbon intensity (CI) of oils. Second, there is a lack of comprehensive geographically rich datasets that would allow evaluation and monitoring of life-cycle emissions from oils. We have previously worked to address the first challenge by developing open-source oil-sector CI modeling tools. Here, we address the second challenge by using these tools to model well-to-refinery CI of all major active oil fields globally—and to identify major drivers of these emissions.
We estimate emissions in 2015 from 8966 on-stream oil fields in 90 countries. These oil fields represent ∼98% of 2015 global crude oil and condensate production. This analysis includes all major resource classes (e.g., onshore/offshore and conventional/unconventional) and accounts for GHG emissions from exploration, drilling and development, production and extraction, surface processing, and transport to the refinery inlet (collectively called “upstream” hereafter). These results are based on data from nearly 800 references, including government sources, scientific literature, and public technical reports. Proprietary databases are used to supplement these data when information is unavailable in the public domain (generally for small oil fields). The latest Intergovernmental Panel on Climate Change (IPCC) 100-year global warming potential (AR5/GWP100) factors are used in this work.