Using mobile surface in situ and remote sensing and airborne remote sensing to derive emissions from a producing central California oil field in complex terrain

Abstract

In this study, we demonstrate how under certain wind conditions, a mobile surface in situ platform, Truck MObile trace Gas (TMOG) Surveyor, that includes a ceilometer to derive boundary layer height (BL) can derive emissions. Field in situ and airborne thermal infrared imaging spectroscopy data were acquired by the thermal infrared imaging spectrometer, Mako, for three adjacent, central California producing oil fields (Kern River, Kern Front, Poso Creek) on 14 Sept. 2018. Derived methane (CH4) and carbon dioxide (CO2) emissions from TMOG data were 46.6 ± 15 Mg dy−1 (17 ± 5.6 Gg yr−1) and 3.12 ± 1.02 Mg dy−1 (1140 ± 230 Gg yr−1), respectively, with about half the CH4 from near-field point-source plumes and half from a well-mixed far field plume. Uncertainty was 33 % from the Monte Carlo simulations. Mako data confirmed that emissions were in the far field and there were no strong, buoyant plumes. The survey vertically profiled a nearby mountain to measure winds at the boundary layer top and validate BL using in situ data.The CH4 to CO2 emissions ratio for plume matched reservoir composition to better than 10 %. The plume anomaly CH4 to ethane emissions ratio suggested ethane emissions of around 200 kg dy−1 (74 Mg yr−1). Mako data in 2015 and concurrent data in 2018 confirmed that most emissions were from distant plumes in the Poso Creek and Kern Front fields.