* — \ *1 PROt^ Memorandum: Summary of Revisions to Oil and Gas Tool ------- ------- EPA-454/B-20-027 March 2013 Memorandum: Summary of Revisions to Oil and Gas Tool U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Air Quality Assessment Division Research Triangle Park, NC ------- %ERG MEMORANDUM TO: Roy Huntley, US EPA Jennifer Snyder, US EPA FROM: Mike Pring, Eastern Research Group, Inc. (ERG) Regi Oommen, Eastern Research Group, Inc. (ERG) DATE: March 28, 2013 SUBJECT: Summary of Revisions to Oil and Gas Tool The purpose of this memo is to summarize the changes that have been made to the draft oil and gas area source emissions estimation tool since the previous version. In addition, we have provided a discussion of changes proposed prior to finalization of Version 1 of the tool in June of2013. Activity Data 1) Production data has been obtained for Indiana and Illinois. 2) Well count data for Texas and Kansas has been updated using information provided by Texas and Kansas. 3) Drilling and completion data for Utah has been updated using information provided by Utah. 4) Hours of operation of gas-actuated pumps have been revised to 8,760 from 8,765. 5) A transcription error for California between well count and feet drilled has been corrected. Emission Estimation Algorithms 1) Several errors in the emission estimation algorithms used in the Access tool have been corrected. These corrections resulted in revised emissions estimates for: • Associated Gas Flaring SO2 • HAPs from engines (HAPs now reflect control where VOC is controlled) • Crude Oil Tank Flaring SO2 • Dehydrator Reboiler • Dehydrator Stillvent • Gas Actuated Pumps • Well Completions • 4-Stroke Lean Burn engine emissions of BTEX and Formaldehyde (previous version erroneously used 4-Stroke Rich Burn emission factors) 2) Natural gas composition data developed by EPA for regulatory development purposes has been used as the default profile for the non-CenSARA basins for several categories. Gas composition profiles developed under this effort have been used for: • Liquids Unloading (Gas Wells) • Associated Gas Venting (Oil Wells) ------- • Fugitives (Gas Wells) • Gas-Actuated Pumps (Gas Wells) • Mud Degassing (Oil and Gas Wells) • Pneumatic Devices (Gas Wells) • Well Completions (Oil and Gas Wells) Attachment A provides the reference used to update these profiles. Tool Updates In addition to the activity and emission estimation updates listed above, other changes to the tool include: 1) Revising the spatial resolution of all input data from the basin level to the county level. 2) Revising the name of the "Nemeha" basin to "Nemaha". 3) Removing duplicate fields for Mud Degassing and Produced Water. 4) Revising/standardizing field names (see Attachment B for a cross-walk of the revised field names as compared to the previous version). 5) Updating the glossary and definitions to reflect the revised/standardized field names. 6) Removing the EIS export tables to an external database (the functionality remains). 7) Renaming of the "Blowdowns" source category to "Liquids Unloading", and of the "Casinghead Gas" source category to "Associated Gas" to match the source category names under Subpart W of the Greenhouse Gas Reporting Rule. Anticipated Changes for Version 1 ( June. 2013) 1) Incorporate updated input data and assumptions provided by Texas and North Dakota. 2) Revise the emission factor used to estimate well completion emissions for hydraulically fractured wells to reflect an EPA emission factor of 9,000 MCF/completion. In addition, hydraulically fractured wells will be identified using the same approach as used to compile the 2011 Annual Greenhouse Gas Inventory. These counts will also be used to estimate emissions from hydraulic fracturing engines (currently based on the count of horizontal well completions). 3) Well counts will be based on an average monthly count of producing wells instead of a total annual count of producing wells. 4) Drilling information from RigData will be used to supplement information from HPDI to gapfill activity data related to drilling. 5) Update input and activity data as received from states during the review period. ------- Attachment A - EPA Natural Gas Composition Data Memo (see file "Composition of Natural Gas for Use in the Oil and Natural Gas Sector Rulemaking.pdf') ------- Attachment B - EPA Natural Gas Composition Data Memo (see file "Tool Glossary _crosswalk.xlsx") ------- United States Office of Air Quality Planning and Standards Publication No. EPA-454/B-20-027 Environmental Protection Air Quality Assessment Division March 2013 Agency Research Triangle Park, NC ------- |