Citation:

Stovern, M., J. Murray, C. Schwartz, Cynthia Beeler, AND E. Thoma. Understanding Oil and Gas Pneumatic Controllers in the Denver-Julesburg Basin using Optical Gas Imaging. JOURNAL OF THE AIR & WASTE MANAGEMENT ASSOCIATION. Air & Waste Management Association, Pittsburgh, PA, 70(4):468-480, (2020). https://doi.org/10.1080/10962247.2020.1735576

Impact/Purpose:

Under its next generation emissions measurement (NGEM) program, the U.S Environmental Protection Agency (EPA), Office of Research and Development (ORD), Center of Environment Measurement and Modeling (CEMM) is working with a range of partners to develop and test NGEM tools that can assist facilities in detection and management of air pollutant sources. This project contributes to the general advancement and communication of NGEM through the use of optical gas imaging (OGI) to advance understanding and control of emissions from the oil and natural gas (ONG) sector. As detailed in the below abstract, this project, called The Denver-Julesburg (DJ) Basin Well Pad Pneumatic Controller (PC) Study, seeks to improve information on PC emissions from upstream ONG production operations. PCs are widely used in ONG production for process control and safety functions. Because of the large numbers of PCs in use, they are among the largest methane emission source categories in ONG field operations.

Description:

In the spring of 2018, a 10-day field study was conducted in Colorado’s Denver-Julesburg oil and natural gas production basin to improve information well pad pneumatic controller (PC) populations and the use of optical gas imaging (OGI) to identify PCs with potential maintenance issues (MIs) causing excess emissions. A total of 500 NG-emitting PCs servicing 102 wells (4.9 PCs/well) were surveyed at the 31 sites operated by seven different companies. The PCs were characterized by their designed operational function and applications, with 83% of the PC population identified intermittent PCs (IPCs). An OGI inspection protocol was used to investigate emissions on 447 working PCs from this set. OGI detected continuous emissions from 11.6% of observed IPCs and these were classified as experiencing some level of MI. Fourteen emission measurements were conducted on IPCs in this category using a high-volume sampling device with augmented quality assurance procedures with observed emissions rates ranging from 0.1 up to 31.3 scf/hr (mean = 2.8 schf/hr). For PCs with continuous depressurization type (CPC), 38.2% had continuous emissions detected by OGI. Four emission measurements were conducted on CPCs with one unit exceeding the low bleed regulatory emission threshold with an emission rate of 9.9 scf/hr (mean = 4.2 scf/hr). Additional information was collected on PC actuation events, as observed with OGI, to demonstrate how facility production can affect the relative importance of emissions from actuation events and continuous emissions caused by MIs on the PC average emission rates.

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