Laser gas detector systems for greenhouse gas emissions monitoring

Two types of portable laser based gas detector for measuring emissions of the greenhouse gases carbon dioxide (CO2) and methane (CH4) from oil and gas operations are described. A scanning open path detector was developed within a Cooperative Research and Development Agreement (CRADA) with the USEPA. This system scans multiple paths across an area source in rapid succession, enabling calculation of concentration profiles and emissions fluxes. A vehicle mounted detector acquires ambient CH4 or CO2 data with excellent concentration and spatial resolution. The long wavelength laser used enables CO2 resolution of 5 ppm. Field data from both types of detector are presented.

There has recently been a significant increase in interest in detecting and quantifying emissions of the greenhouse gases (GHG) carbon dioxide (CO2) and methane (CH4) from oil and gas operations – both in Alberta and other jurisdictions in North America and Europe. The primary drivers for this increased interest are: new and pending legislation requiring demonstrated reductions in GHG emissions from oil and gas facilities; financial incentives in the form of emissions trading credits; strong interest in CO2 sequestration in abandoned oil and gas reservoirs as a technique for CO2 emissions reduction.

A major barrier to effective implementation of emissions reduction and trading plans is the absence of real emissions measurements to establish baselines and confirm reductions. This is especially true for fugitive emissions from area sources comprised of distributed or multiple point sources such as natural gas production and processing facilities in Alberta. Several oil and gas company personnel responsible for GHG emissions inventories and reductions have recently complained that traditional point monitoring technologies and emissions bagging schemes are either too laborious, too expensive or provide insufficient coverage to enable cost effective continuous monitoring.