Semester

Summer

Date of Graduation

2026

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

Derek Johnson

Committee Member

Cosmin Dumitrescu

Committee Member

Christopher Ulishney

Abstract

 

As the US natural gas (NG) sector continues to grow, concerns have increased regarding the effects and increasing volume of greenhouse gases emitted into the atmosphere. While NG is a cleaner burning fuel than diesel and gasoline, unburned methane (CH4) has a global warming potential (GWP) 27-30 times that of carbon dioxide (CO2). To better quantify CH4 emissions on NG sites, the US Department of Energy (DOE) granted West Virginia University (WVU) funding to collect direct measurements at well sites and compressor stations.

In this work, a total of 18 sites, including controlled and uncontrolled tanks, were surveyed and audited for emissions. A full flow sampler (FFS), created at WVU, was deployed at these sites to directly quantify CH4 emissions from storage tanks. Emissions factors (EFs) were calculated based on this raw data, in addition to an estimated EF based on Henry’s Law. These EFs were then compared to those from the Environmental Protection Agency (EPA) and other studies. EFs for tanks with production data are expressed in kg of CH4 per barrel (bbl) (equivalent to 42 gallons) of produced water (PW). EFs for controlled tanks were expressed in kg of CH4/tank/yr.

PW for nine uncontrolled sites modeled by Henry’s Law averaged an EF of 0.061 kg/bbl, 20% more than the US EPA EF of 0.0508 kg/bbl. The average PW EF for the nine uncontrolled sites derived from raw collected data was 1.16  kg/bbl, more than 20 times that of the EPAs current PW EF. The average PW EF for the remaining nine controlled sites were 606 kg/tank/yr. The average condensate and make tank EFs for those sites were 8.04 kg/tank/yr and 1878 kg/tank/yr, respectively. These EFs were all found through calculations from raw field data. The two sites with the largest emissions included Site 4 and Site 8, both uncontrolled, with emission rates of 7331 g/hr and 3168 g/hr, respectively. It is important to note that the 7331 g/hr value was a minimum value as the lower explosive limit was reached. These two sites, comprising 11.1% of the sites (by count, n=2), produced 49.1% of the total emissions by mass. This supports the findings of other works where the top 10% of emissions sources made up roughly 50% of the total mass emissions. By excluding the top 11.1% of sites, the EF was 1.13 kg/bbl. The decrease in EF is minor and a result of Site 4 and Site 8 producing 134 and 80 bbl/d of water, the first and third highest water producing sites of the nine uncontrolled sites. There was no correlation between emissions and water production, gas throughput, or tank headspace composition.

Download

Share

COinS