Carbon intensity (CI) is a quantitative measure of the carbon generated per unit of energy and is a useful way to compare various crude oils. The CI of oil production varies widely across oil plays. Life cycle extraction from some unconventional plays (e.g., tar sands) has some of the highest CIs, but even many North American shale plays have high carbon intensity. Middle East crudes range from some of the lowest to some of the highest global values of CI. Flaring and venting of associated or non-associated natural gas dramatically increases Most approaches to estimating CI have been either retrospective or current. This paper illustrates varying CI over time and integrates this with production forecasts to calculate the CO2 equivalent emissions of reserves at any point in time.
This paper applies peer-reviewed processes across shale activity in North America and estimates current and future carbon intensity. We perform well-to-refinery calculations of CI for major unconventional oil plays in North America and introduce a methodology for estimating future values. This approach accounts for emissions from exploration, drilling and completions, production, processing, and transportation. The analysis tool is an extension of the open-source engineering-based model, developed at Stanford University, called the Oil Production Greenhouse Gas Emissions Estimator (OPGEE).
OPGEE makes estimates of emissions by using up to 50 parameters for each modeled field. Data sources include government sources, technical papers, satellite observations, and commercial databases.
Results/Observations/Conclusions: Future estimates of venting, flaring, and fugitive emissions remain the largest drivers of CI. However, increasing energy costs associated with artificial lift, water handling and (relative) increases associated with production equipment become dominant over time. Since CI is a per-barrel measure CI rises significantly over time.
Significant carbon taxes materially increase economic limits. Such increases occur later in the life of wells when operating margins are already declining. The total impact on NPV is not great at early time but could result in very material accelerations of abandonment times and nontrivial volumes of reserves lost. Actions to lower Cl appear profitable even without carbon taxes.
