Estimating Oil and Gas Storage Tank Control Factors from GHGRP Data

This document details the development of Texas basin-specific control factors for upstream oil and gas storage tanks using U.S. EPA’s Greenhouse Gas Reporting Program (GHGRP) data.The GHGRP collects information from oil and gas operators for a number of equipment types, including the use of VRU’s and flares on upstream oil and

gas storage tank emissions. As of August 31, 2015, the most recent publically available GHGFRP storage tank control data included in EPA’s Envirofacts online database (available at: http://www.epa.gov/enviro/facts/ghg/customized.html) is for calendar year 2013 data. The control factors detailed in this document are therefore based on 2013 GHGRP data. Once the 2014 GHGRP data becomes available, the control factors will be re-evaluated and updated as appropriate.

Obtaining the GHGRP dataThe storage tank data available in EPA’s Envirofacts database is broken into three different tables, based on the method of estimating their emissions:

Emissions Calculation Method

Type of Tanks Data reported

Method 1 or 2 > 10 bbls/day, with a separator upstream of the tank

County-level

Method 3 or 4 > 10 bbls/day, no separator upstream of the tank

County-level

Method 5 < 10 bbls/day Basin-level

To query the Envirofacts database, the first step is to choose the subject area you are interested in:

Scroll down, and select the “Petroleum and Natural Gas Systems”:

Next, select the button so you can choose which tables to query:

The three tables containing the storage tank control information are:Emissions Calculation Method Envirofacts Table

Method 1 or 2 W_ATMOS_TANKS_CALC_1_OR_2Method 3 or 4 W_ATMOS_TANKS_CALC_3_OR_4Method 5 W_ATMOSPHERIC_TANKS

Please note: it appears that the names of two tables have been mixed up, since you would expect the Method 5 data to be found in table “W_ATMOS_TANKS_CALC_5” but it is instead found in table “W_ATMOSPHERIC_TANKS”.Select the table with the information you are interested in:

After selecting the table you are interested in, scroll down to the bottom of the page, and select the button in order to choose the columns you want to query:

In each table, there are a number of columns of data. The columns I chose for each of the three tables are:

Method 1 or 2(W_ATMOS_TANKS_CALC_1_OR_2)

Facility NameReporting YearHydrocarbon TanksSub Basin IdentifierTanks with FlaringTanks with Vapor Recovery

Method 3 or 4 Facility Name

(W_ATMOS_TANKS_CALC_3_OR_4)

Reporting YearSub Basin IdentifierTanks On Well PadsTanks On Well Pads with FlaringTanks On Well Pads with Vapor Recovery

Method 5 Facility Name

(W_ATMOSPHERIC_TANKS) Reporting YearCalculation Method Five Production Fraction with FlaringCalculation Method Five Count of Tanks on Well PadsCalculation Method Five Production Fraction with Vapor Recovery

After choosing the columns, scroll down to the bottom of the page, and select the button in order to enter the search criteria:

When querying all three tables, I set the Reporting Year to 2013. For tables W_ATMOS_TANKS_CALC_1_OR_2 and W_ATMOS_TANKS_CALC_3_OR_4, companies report their data at the county-level, and the Sub Basin Identifier field contains the sub-basin number, county name, state abbreviation, and the oil and gas formation. In order to retrieve all of the data for Texas, I set the Sub Basin Identifier to Containing TX, then selected the button to search the database:

For table W_ATMOSPHERIC_TANKS, companies report their data at the sub-basin level. A list of sub-basin numbers and the corresponding counties can be found at: http://www.ccdsupport.com/confluence/display/help/Subpart+W+Basin+and+County+Combinations . A majority of companies include the basin number in their Facility Name. In order to retrieve data for Texas, I queried the table multiple times, each time setting the Facility Name to Containing one of the basin numbers that included Texas counties:

The list of basin numbers that included Texas counties:220 260 350 360400 415 420 425430 435

[Note: basin numbers 405, 410, and 465 also include Texas counties; however, no records were returned for those basins.]After querying the data for Texas for each of the three tables, I copied the data into excel spreadsheets. Then, I loaded the data into an Access database, one table for each of the three sets of data. The resulting number of records for each table was:

Calculation method Number of recordsMethod 1 or 2 694

Method 3 or 4 225Method 5 220