In our Case Study, Zero Routine Flaring Targets Cannot Be Met Without Addressing Tank Battery Flaring and Venting, we cover emissions measurement in more depth and provide a case study demonstrating how one E&P operator discovered tank batteries were the largest source of well site emissions.
Case Study Summary
In light of more stringent emissions rules and environmental performance mandates to achieve net-zero emissions and eliminate routine flaring, current practices regarding tank venting and flaring are being reexamined.
In this article, we cover why routine flaring of tank vapor gas is a regular occurrence at many production facilities even when they have all the required permits. We also focus on the best practices for minimizing upstream emissions at oil and gas production facilities.
Tank Battery Emissions in the Spotlight
The spotlight on upstream emissions is moving from the routine flaring of associated gas to the tank battery. As operators become more proficient in leak detection and repair, attention is turning to other significant sources of emissions.
The chart below illustrates EPA Greenhouse Gas Inventory estimates of upstream emissions from oil and gas operations for 2019, the most recent year for which data is available.
EPA estimates identify tanks and tank flares the THIRD largest source of upstream emissions on a CO2e basis, after pneumatic devices and routine flaring, accounting for 11% of total upstream Greenhouse Gas (GHG) emissions.
Total tank emissions are the result of leaks, tank venting and downstream flaring of low-pressure vapor from both oil and water storage tanks.
Mis-Estimating Emissions
An accepted data source for completing and securing air permits for oil and gas development is the EPA’s Greenhouse Gas Inventory estimates. These estimates are also used as the basis for developing well site and facility emissions control plans.
It is a common occurrence, however, that routine flaring of tank vapors continues even at permitted sites. Tank flaring generates GHG emissions and nitrates of oxide (NOx), which is a precursor to ozone pollution, just like flaring of associated gas at wells not yet connected to pipeline infrastructure.
Statistically, the EPA data is useful to policy makers, but it is not specific enough for developing and emission control plan that will be effective in eliminating all routine flaring and venting at production sites.
Boots on the Ground – Results from the Field
One upstream operator conducted a study to directly measure emissions at its production facilities to get an accurate, boots-on-the-ground, perspective of emissions. The operator used a variety of monitoring techniques, including continuous monitoring at the fence line, aircraft, drones and vehicle-mounted sensors to evaluate emissions at 25 central processing facilities.
After several weeks, the results proved that tank batteries were the largest source of measured emissions, and by a wide margin.
The chart below illustrates the emissions volumes by source, as attributed by the operator based on direct, actual measurements on location.
Comparison of EPA Estimates and Field Level Observations
The study found that “…component-level emission factors that are used for EPA reporting do a poor job approximating actual emissions.”
The table below compares the direct measurements observed by the operator at its facilities to EPA emissions estimates often used for air permitting.
The implications for facility design and developing emissions control plans are clear:
- EPA emissions factor estimates are inadequate for addressing tank battery venting and flaring, which are significant sources of production facility emissions.
- Even at permitted facilities, tank flaring continues to be a routine practice.
- Tanks were the primary emission source and emissions did not correlate with production volumes
- Separators, heater-treaters and their associated equipment represented a small share of overall emissions
- Measured emissions were distributed across both high-rate and low-rate facilities in a relatively uncorrelated manner
- Low oil rate facilities cannot be dismissed as negligible
- The tank vent system and flare were seen as more complex issues, in some cases requiring advanced engineering solutions
EcoVapor is committed to helping oil and gas operators take steps toward a zero emissions wellsite. Our technology-based Pathways to Zero help Energy companies simultaneously achieve their environmental performance goals and increase profitability.
About EcoVapor
EcoVapor Recovery Systems provides solutions to pressing oil and natural gas production problems. EcoVapor’s technical team has extensive expertise in vapor recovery processes and includes world-class engineers with an innovative approach to industry challenges. In over 120 installations in all major US basins, our patented ZerO2 solution helps oil and gas producers meet their air emissions and regulatory compliance goals. EcoVapor is headquartered in Denver, Colorado and has field locations in Greeley, Colorado and Midland, Texas.
Contact
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1422 Delgany Street, Suite 100
Denver, CO 80202
Email: Info@EcoVaporRS.com
Phone: 844-NOFLARE (844-663-5273)