HEI Exposure Workshop July 2018

Transcription

1 Overview of Air Emissions from Unconventional Oil and Gas Operations Adam Pacsi, PhD Chevron Energy Technology Company On Behalf of the HEI Industry Group HEI Exposure Workshop July 2018

2 Outline of Presentation Overview of major equipment onsite and regulatory developments Intro to specific sources and control technologies Guided by regional ozone planning inventories NOx and VOC emissions as surrogates for combustion and non-combustion sources Perspective on how methane studies could inform HEI Research

3 Overview of Site Operations and Regulatory Basics

4 Simple Process Flow Diagram (Central Tank Battery)

5 Simple Process Flow Diagram (Central Tank Battery) 1+ per pad site 1+ well

6 US EPA Regulations for Upstream Applicable to constructed, modified, or reconstructed facilities after compliance dates Controls and operational practices for volatile organic compound (VOC) emissions NSPS OOOO (2012) HF Gas Wells Pneumatic Controllers Storage Tanks Compressors NSPS OOOOa (2016) HF Oil Wells Equipment Leaks/Fugitives Pneumatic Pumps Chart above is a simple overview. There are a myriad of complex requirements for compliance that would go beyond an overview.

7 First Model Year US EPA Engine Emission Regulations Performance requirements (Tiers) on new engines for a model year Retirement of older engines over time and replacement with lower emitting models May be local requirements for additional controls or which engines can be permitted PM*10 CO NOx US EPA Non-Road Standards Diesel Engine > 1206 hp Tier 4 Final Tier 4 Interim Tier 2 Tier g/kw/hr

8 Other Programs State Requirements EPA Requirements Operator Voluntary Programs The Environmental Partnership (2017) Pneumatic Controller Manual Liquid Unloading Leak Detection and Repair Center for Responsible Shale Development (2013) Surface and Groundwater Performance Standards Air and Climate Performance Standards Flaring Limits Green Completions Engine Emissions Storage Tank Controls

9 Sources of Air Emissions and Control Technologies

10 Why Draw on Emission Inventories for Ozone Planning? Cover both combustion (~NOx) and non-combustion (~VOC) sources Publicly available from regulatory agencies Introduction to sources Limitations: Level of granularity for a dispersed area source Average operating conditions in a basin

11 Example: 2010 Ramboll Environ Inventory for the Denver Julesburg (DJ) Basin Heaters 3% NOx Emissions Other Engines 15% Venting 4% VOC Emissions Fugitives 12% Drill Rigs 29% Compress ors 52% Pneumatic Devices 17% Tanks 59%

12 What efforts is industry taking to control VOC emissions? Other Sources 8% Venting 4% Fugitives 12% Pneumatic Devices 17% Tanks Fugitives Other Sources VOC Emissions Tanks 59% Pneumatic Devices Venting Data: 2010 Ramboll-Environ DJ Basin Inventory Tank Emissions: Vapor Recovery Systems Flaring Venting Reduced emission completions Pneumatic Controllers High bleed changeouts Leak detection and repair programs

13 Percent of VOC Emissions by Source Category in Basin Basin-to-Basin Variation in VOC Emission Sources 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Bakken (2015) DJ Basin (2010) San Juan (2014) Marcellus (2016) Associated Gas Flaring and Venting Loading Operations Tank Emissions Fugitives Pneumatic Pumps Pneumatic Controllers Other Bakken, DJ Basin, and San Juan Ramboll Environ Inventories Marcellus PA DEP reported data

14 Hazardous Air Pollutant (HAP) Emission Inventories Pennsylvania Department of Environmental Protection (PA DEP) requires annual reporting of HAP emissions from unconventional oil and gas operations Barnett Shale Special Emission Inventory by TCEQ Individual site estimates are included in many state permits

15 PA DEP Inventory in 2016 FUGITIVE 7% DEHY 23% COMPLETI ON 16% ENGINE 47% ENGINE 96% Reported Benzene Emissions Reported Formaldehyde Emissions

16 Methane Emission Studies

17 Methane as a Surrogate for Other Emissions from Unconventional Operations Confounding sources possible with ambient methane measurements Ratios to other chemical species is highly variable Simple scaling of off-site methane concentration measurements is not likely to be meaningful. Methane is not necessarily a good proxy for HAPs and other air emissions. Gas Analyses from a Single Unconventional Site Oil Tank - Breathing Water Tank Oil Tank - Flash Sales Gas Wellhead Gas Benzene to Methane Ratio in Process Stream at One Site

18 Applicable Lessons Learned from Methane Emission Research Early planning on scaling/contextualizing results Recent studies show a "fat tail" (small number of sources responsible for a large portion of emissions) for methane emissions. Multiple measurement methods and inter-comparison studies are vital. Spatial and temporal variations in emissions and activities are key. Operational insights are key for understanding results.

19 Thank You