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Environment - Air

Energen has worked for many years to reduce methane emissions. These efforts include voluntary implementation of emissions reduction activities and equipment as well as compliance with methane emission control, reduction, and reporting regulations. In addition, Energen’s strategic decision in 2009 to shift its focus from natural gas to oil has significantly reduced the company’s methane footprint.

The company’s transformation to a leader in the drilling and development of horizontal oil formations in the Midland and Delaware basins culminated in 2016 with the sale of Energen’s remaining assets in the San Juan Basin, one of the largest onshore natural gas producing regions in the United States. Energen also sold its gassier assets in the western portion of the Delaware Basin in 2016. Several years prior, Energen sold its gas assets in the Black Warrior Basin and the north Louisiana/east Texas area; and in 2014, Energen sold its legacy natural gas utility. Today, Energen’s only gas production is associated with its oil production.

The mix of the company’s production from continuing operations in 2016 was 80% oil and liquids and 20% natural gas. Underscoring the company’s strategic shift to oil producer and the resulting reduction of its methane footprint, Energen has cut its annual natural gas production in just five years by 67%, from 11,953 MBOE in 2011 to only 3,905 MBOE in 2016.

Since 2003, the company has participated in the United States Environmental Protection Agency (EPA) Natural Gas STAR Program. Gas STAR is a voluntary program that encourages oil and natural gas companies to employ technologies and practices to improve operational efficiency and reduce methane emissions. Since joining, the company has achieved Gas STAR-estimated cumulative methane emission reductions of more than 9.0 billion cubic feet (Bcf) through 2016. According to the EPA, this corresponds to more than 4.3 million metric tons of carbon dioxide-equivalent reductions, which also equates to carbon sequestration of more than 3 million acres of pine forest.

Energen achieved these reductions through actions that were voluntary at the time achieved and included:

  • Installation of electric motors on pumping units and compressors previously fueled by natural gas
  • Installation of vapor recovery units (VRUs) at some production tank batteries
  • Installation of pumping units on gas wells with plunger lift to reduce venting while removing fluids from gas well bores
  • Capture of casing head gas by VRU or compressor
  • Reduction of blanket gas on tank battery facility
  • Flaring instead of venting where gas could not be captured into a pipeline system
Reduction of emissions from oil and gas operations into the air continues to be an area of focus at Energen. Like many of its peers in the upstream segment, Energen continues to work diligently with Federal and State agencies to comply with applicable regulations regarding daily operations.

In 2016 the EPA enacted regulation which has a significant impact on operators focused on primarily oil production through the New Source Performance Standard (NSPS) OOOO (a) standard.

Energen’s primary focus continues to be on identified best practices as well as the utilization of proven technology innovations to manage and mitigate the effects of air emissions in its operations.

Examples of these include:
  • Installation of electric instrument air compressors to supply air to control devices at some battery facilities in lieu of natural gas supplied controls.
  • Completion/operational practices that allow for the reduction or, in some cases, elimination of flaring gas during completion activities. Since 2015 Energen has reduced flaring during completion activities from an average of 15 days to just over 3.5 days. Reductions of this magnitude are largely accomplished by having operational infrastructure in place prior to completion activities which allows gas to be routed to a natural gas sales pipeline.
  • Leak Detection and Repair (LDAR) activities. In 2016 NSPS OOOO (a) mandated implementation of an LDAR program at affected facilities to identify and eliminate fugitive emissions from tanks and other components. Energen utilizes a third-party consultant’s certified thermographer to identify leaking components and work with operations personnel to repair leaks as soon as possible.
  • Installation of emission control devices at storage tank facilities. Vapor recovery units capture Volatile Organic Compound (VOC) emissions in the tank’s head space that are generated from producing oil into a storage tank. These VOC’s contain merchantable components which are then routed to a natural gas sales line at the facility. Utilizing the latest thief hatch and pressure regulation technology on oil and water storage tanks also minimizes emissions from storage tanks.
  • Use of Lease Automatic Custody Transfer (LACT) units. LACT units allow for oil sales directly into a pipeline rather than allowing truck loading emissions. Off-gas comes from displacing and flashing gas into an oil transport trailer during custody transfer operations. An additional benefit is that this reduces diesel emissions from truck traffic on our locations.
  • Flaring instead of venting. Energen has installed “emergency flares” at locations that allow for flaring of gas instead of venting. Operational flaring occurs periodically at facilities during upset and maintenance activities or in certain emergency situations. Flaring in lieu of venting allows for safer operations and reduced overall emissions due to the combustion of the associated gas volume.
Each owner or operator of onshore petroleum and natural gas production wells and related equipment reports under subpart W the combined emissions for all wells that they own or operate within each hydrocarbon basin. The greenhouse gas (GHG) data is entered in to the Greenhouse Gas Reporting Program (GHGRP) and is available for viewing by interested parties on the EPA’s web site.

The table below is data from Energen’s reported GHG emissions for 2016:

Subpart W Reported emissions (mtons) 
 Carbon Dioxide 409,518
Methane2,640
Nitrous Oxide1

Energen’s top three GHG emission sources are combustion, flare stacks, and atmospheric tanks.

Energen is committed to reducing air emissions and doing its part to improve air quality in the Permian Basin of west Texas.