卡内基国际和平基金会-Drilling-Down-on-Oil-The-Case-of-California-s-Complex-Midway-Sunset-Field_1页_2mb

California Midway Sunset Emissions Summary

Core Content

This document provides an analysis of greenhouse gas (GHG) emissions associated with California's Midway Sunset crude oil, comparing them to those of Canadian oil sands. It outlines three different emission scenarios based on proxy assays, as verifiable data on oil assays and steam-to-oil ratios (SOR) for Midway Sunset is currently lacking.

Main Points

• GHG Emissions Overview: GHG emissions for Midway Sunset crude are presented in kilograms of CO₂ equivalent per barrel of crude (kgCO₂eq./bblCrude). These values are estimated using proxy assays due to the lack of comprehensive and updated data.

• Emission Scenarios:

  • Scenario A: Uses a publicly available assay from K novel, with an API gravity of 22.6° and a SOR of 5.79. It is not considered fully representative of the entire Midway Sunset field.
  • Scenario B: Utilizes a proxy assay from Venezuela Tia Juana, with an API gravity of 12.1° and a SOR of 5.79. It is believed to better represent the 13° API gravity Midway Sunset crude that serves as a benchmark.
  • Scenario C: Employs a proxy assay from Alberta Energy, with an API gravity of 8.1° and a SOR of 7.50. It is considered a better approximation for the higher end of GHG emissions in lower quality Midway Sunset crude, similar to Canadian oil sands.

• Comparison with Oil Sands: The document suggests that certain scenarios of Midway Sunset emissions may be comparable to or even exceed those of some Canadian oil sands, depending on the quality of the crude and the SOR used in the refining process.

• Uncertainties and Notes:

  • Emissions values may not sum up exactly due to rounding.
  • Sulfur content in different Midway Sunset crudes is not consistently reported, which may affect the accuracy of proxy assays.
  • The sulfur content of proxy assays may not accurately reflect that of Midway Sunset crude, but this does not significantly alter GHG estimates in the Oil Carbon Intensity (OCI) model.

Key Information

• Production and Refining Emissions: The document distinguishes between production and refining GHG emissions. It highlights that refining emissions are estimated using proxy assays and are subject to variability based on the crude's properties and refining processes.

• API Gravity and SOR: API gravity and steam-to-oil ratio are key factors influencing GHG emissions. Lower API gravity and higher SOR generally correlate with higher emissions.

• Proxy Assays: Proxy assays are used to estimate emissions for Midway Sunset due to the lack of direct data. These proxies are based on similar crude oils from other regions, such as Venezuela and Alberta.

Conclusion

The analysis underscores the complexity of estimating GHG emissions for Midway Sunset crude due to the lack of consistent and updated data. It suggests that emissions could vary significantly depending on the crude's quality and the refining process. While Scenario A is based on actual data, Scenarios B and C are considered more representative of the broader range of Midway Sunset crude, with Scenario C possibly reflecting the higher end of emissions. The comparison with Canadian oil sands indicates that Midway Sunset emissions could be on par with or even exceed those of some oil sands operations, depending on the specific conditions and assumptions used in the modeling.