Abstract. Accurate and comprehensive quantification of oil and gas methane emissions is pivotal in informing effective methane mitigation policies, while also supporting the assessment and tracking of progress towards emissions reduction targets set by governments and industry. While national bottom-up source-level inventories are useful for understanding the sources of methane emissions, they are often unrepresentative across spatial scales, and their reliance on generic emission factors produces underestimations when compared with measurement-based inventories. Here, we compile and analyze previously reported ground-based facility-level methane emissions measurements in the major US oil and gas producing basins and develop representative methane emission profiles for key facility categories in the US oil and gas supply chain, including well sites, natural gas compressor stations, processing plants, crude oil refineries, and pipelines. We then integrate these emissions data with comprehensive spatial data on national oil and gas activity to estimate each facility’s mean total methane emissions and uncertainties, from which we develop a mean estimate of national methane emissions, resolved at 0.1° × 0.1° spatial scales (~10 km × 10 km). From this measurement-based methane emissions inventory (EI-ME), we estimate total US national oil/gas methane emissions of 15.7 Tg (95 % confidence interval of 14–18 Tg) in 2021 which is 2.5 times greater than the EPA Greenhouse Gas Inventory. Our estimate represents a mean gas production-normalized methane loss rate of 2.6 %, consistent with recent satellite-based estimates. We find significant variability in both the magnitude and spatial distribution of basin-level methane emissions, ranging from <1 % methane loss rates in the gas-dominant Appalachian and Haynesville regions to >3–6 % in oil-dominant basins, including the Permian, Bakken, and the Uinta. Additionally, we present and compare novel comprehensive wide-area airborne remote sensing data and results of total area methane emissions and the relative contributions of diffuse and concentrated methane point sources as quantified using MethaneAIR in sub-regions of the Permian and Uinta basins that together indicate diffuse area sources accounting for the majority of total regional oil and gas emissions. Our assessment offers key insights into plausible underlying drivers of basin-to-basin variabilities in oil and gas methane emissions, emphasizing the importance of integrating measurement-based data in developing high-resolution, spatially explicit methane inventories in support of accurate methane assessment, attribution, and mitigation. The high-resolution spatially explicit EI-ME inventory is publicly available at https://doi.org/10.5281/zenodo.10734300 (Omara et al. 2024).

中文翻译：

---

构建基于测量的美国石油和天然气甲烷排放的空间明确清单

摘要。准确、全面地量化石油和天然气甲烷排放对于制定有效的甲烷减排政策至关重要，同时也支持评估和跟踪政府和行业设定的减排目标的进展情况。虽然国家自下而上的源级清单有助于了解甲烷排放源，但它们往往在空间尺度上不具有代表性，而且与基于测量的清单相比，它们对通用排放因子的依赖会导致低估。在这里，我们汇编和分析了之前报告的美国主要石油和天然气生产盆地的地面设施水平甲烷排放测量数据，并为美国石油和天然气供应链中的关键设施类别（包括井场、天然设施）制定了具有代表性的甲烷排放概况。气体压缩机站、加工厂、原油精炼厂和管道。然后，我们将这些排放数据与国家石油和天然气活动的综合空间数据相结合，以估算每个设施的平均总甲烷排放量和不确定性，从中我们得出国家甲烷排放量的平均估算值，在 0.1° × 0.1° 空间尺度上解析（~ 10公里×10公里）。根据基于测量的甲烷排放清单 (EI-ME)，我们估计 2021 年美国国家石油/天然气甲烷排放总量为 15.7 Tg（95% 置信区间为 14-18 Tg），是 EPA 温室气体排放量的 2.5 倍存货。我们的估计代表平均天然气产量标准化甲烷损失率为 2.6%，与最近基于卫星的估计一致。我们发现流域甲烷排放量的大小和空间分布存在显着差异，从以天然气为主的阿巴拉契亚和海恩斯维尔地区的<1％甲烷损失率到以石油为主的盆地（包括二叠纪）>3-6％ 、巴肯和尤因塔。此外，我们还介绍并比较了新的综合广域机载遥感数据和总面积甲烷排放量的结果，以及使用二叠纪和尤因塔盆地次区域中的 MacetAIR 量化的扩散和集中甲烷点源的相对贡献，这些数据共同表明分散区域源占区域油气排放总量的大部分。我们的评估提供了对石油和天然气甲烷排放盆地间差异的潜在驱动因素的重要见解，强调了整合基于测量的数据在开发高分辨率、空间明确的甲烷清单中的重要性，以支持准确的甲烷评估、归因和缓解措施。高分辨率空间明确的 EI-ME 清单可在 https://doi.org/10.5281/zenodo.10734300 上公开获取（Omara 等人，2024）。