The focus to reduce greenhouse gases (GHGs) – especially methane (CH4) – from oil and gas (O&G) operations is resulting in the evaluation and quantification of all potential GHG emission sources. The attention at this time is on CH4 emissions from sources at the exploration, production, gathering, processing, transmission and distribution sectors. CH4 from many O&G emission source types have been measured and quantified by projects funded by industry and nongovernmental organizations. The focus could shift to combustion sources (e.g., flares, internal combustion engines, heaters) as the venting sources are further quantified and reduced.
Smart companies will implement a plan to reduce their GHG emissions and minimize liabilities and impacts from increased costs of emitting GHGs into the atmosphere.
The drivers for reducing GHGs from O&G operations include the following:
- The recent Paris 21st Council of Parties (COP21) of the United Nations Framework Convention on Climate Change (UNFCCC)
- The President’s Climate Action Plan to reduce CH4 emissions by 40 to 45% from 2012 levels by 2025
- Proposed NSPS OOOO rule changes specifically list CH4 as a regulated pollutant and expand the regulation to oil wells, pneumatic pumps that use natural gas and leak detection and repair (LDAR) of fugitive emission sources. Emission controls that are used to control VOCs are recognized to also be effective for CH4.
- Expected U.S. Department of Interior regulations to minimize flaring and venting from federal lands and waters.
- Voluntary efforts such as the EPA Natural Gas STAR Program and industry ONE Future Coalition
- Increasing calls for a carbon tax on petroleum products produced at the wellhead and GHG emission pollutant fees based on actual GHG emissions
- Future liabilities associated with GHG emissions from past operations
At present, the following venting sources are covered by existing air quality regulations in NSPS OOOO:
- Crude oil/condensate and produced water storage tanks
- Pneumatic controllers that use natural gas
- Hydraulically fractured gas wells
- Compressor seals
- Equipment Leaks at Natural Gas Processing Plants
Future natural gas venting targets based on proposed regulations, recent studies and because they vent VOCs and CH4 include:
- Hydraulically fractured oil wells – so all hydraulically wells would have emission control requirements
- Equipment Leaks at oil and gas production facilities upstream of natural gas processing
- Pneumatic pumps (e.g., Wilden diaphragm, chemical injection) that use natural gas
- Well venting from liquids unloading
- Glycol dehydration units
GHG combustion sources that could be targeted for future regulation:
- Routine flaring of associated wellhead gas and storage tank vent gas
- Internal combustion engines, heater, reboilers - (not likely in near future since no current effective emission control method other than fuel efficiency measures)
Smart Planning and Response
O&G operators have been designing and operating their facilities with the objective of complying with the current NSPS OOOO regulations and will continue to do so as the regulations evolve. Prudent operators should consider taking steps to further reduce and minimize their GHG emissions from venting and combustion sources.
Optimize Operations and Minimize Air Emissions
- Standardize facility design and equipment used to minimize potential emissions.
- Consolidate production from several wells to a centralized battery for separation and processing. This minimizes duplication of equipment (e.g., glycol dehydrators, storage tanks, heaters, etc.) and can make it more economic to use vapor recovery units (VRUs) to capture storage tank vapors.
- Use VRUs in place of flares and enclosed combustors to recover storage tank vent gas.
- Implement systems to routinely:
- Inspect, maintain and repair vapor recovery units (VRUs) and flares/enclosed combustors.
- Monitor and repair leaks from storage tank thief hatches and other facility equipment leaks.
- Optimize operating pressures and temperatures of separators to reduce flashing emissions at the storage tanks. The lower the operating pressure of a separator/heater treater dumping to a storage tank, the lower the amount of flash gas liberated in the storage tank.
- Optimize the glycol circulation rate for glycol dehydrators. Doubling the glycol circulation rate can double VOC and CH4 venting emissions from the glycol dehydrator still column vent and flash tank.
- Use HY-BON/EDI’s IQR survey service to find opportunities to recover vent and flare gas.
- Involve field operations personnel in efforts to minimize air emissions. This can be included in Safety meetings and become a part of the existing “Safety Culture” that can include air emission reductions.
Know Your GHG Emissions
- Implement a system to track, quantify and document GHG emissions from all operations – even if not required by the EPA Mandatory GHG reporting rule.
- Mine data from the annual GHG emission data to find opportunities to further reduce emissions.
- Use some method to document GHG reductions. This may be important in future if need offsets for existing/future GHG emissions.
- Report GHG emissions via a voluntary program such as the Energy Information Agency (EIA) Section 1605(b) program, and The Climate Registry.
Smart Response with HY-BON/EDI
Let HY-BON/EDI be your response to being proactive. We can help your company reduce GHG emissions, stay in compliance with emission regulations and make your company money. HY-BON/EDI’s vent gas management (VGM) system is a cost effective way to take this issue off of your plate. We can assist by accurately quantifying emissions and use “best in class” vapor recovery units (VRU), Vapor Recovery Towers (VRT) and enclosed combustors (ECU) to comply with Quad O storage tank emission control requirements.