Continuous monitoring of methane emissions on 14 Permian Basin natural gas production facilities, links to operations and mitigation

Abstract:

Methane emissions from the oil and gas sector represent an important component of regional and global methane budgets. Better understanding of emissions characteristics – for example emission rates, links to operations/causes, and frequency/intermittency – is being supported now, for the first time, with the maturation of continuous monitoring technologies and methodologies.

Continuous monitoring, or the characterization of emissions with high enough frequency to yield rapid mitigation and investigation of even short-lived events (e.g. hours to days), is increasingly recognized as a critical element of regulations and practices concerning industry Leak Detection and Repair (LDAR) programs. Traditional LDAR has required only infrequent (e.g. monthly, quarterly or yearly) inspection of natural gas production infrastructure for malfunctioning equipment and leaks. Given known intermittency of sources from this sector and the potential for substantial emissions from infrequent or rare events, continuous monitoring has been proposed as a solution for more effective LDAR, mitigation efforts and understanding of emissions.

In this study, we present multi-month timeseries of real-time, automated, continuous emissions monitoring at multiple sites with a major operator in the Permian Basin. Long, open path measurements with a dual-frequency comb spectrometer provided uninterrupted measurements of 14 sites with a single instrument. We will show baseline emissions and link emissions aberrations to LDAR-confirmed events including vent system flaws, clogged flame arrestors, control valve failures, and infrastructure design flaws. The dual-frequency comb system detected abnormal emissions, notified the operator automatically and in real-time (<30 minutes), and confirmed return to baseline emissions following operator repairs.