[vc_row animation=””][vc_column width=”1/1″][vc_column_text]Methane (CH₄) is considered to be a very potent greenhouse gas (GHG), especially when discussing climate change. Because methane is the primary component of natural gas, many people unfairly associate the natural gas industry as the leading source of methane emissions in the country – especially since domestic natural gas production has increased significantly over the last decade.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]This assumption is further perpetuated by a national inventory of greenhouse gas emissions that the Environmental Protection Agency (EPA) released earlier this year detailing all manmade GHG emissions in 2011. In this report, the EPA estimated that 2,545 Gigagrams (Gg) of methane came from natural gas production activities across the country, with 654 Gg coming specifically from completion flowbacks from wells with hydraulic fracturing. With these findings, the report suggested that 25% of GHG emissions sourced from natural gas comes from the operational processes alone.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]These findings are being disputed in a new study from the University of Texas at Austin which took a closer look at the EPA’s findings and conducted additional research.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/2″]
[/vc_column][vc_column width=”1/2″][vc_single_image image=”5590″ border_color=”” img_link_large=”” link=”” img_link_target=”” img_size=”medium”][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]The University of Texas at Austin study analyzed 190 production sites across the United States and found that compared to the EPA’s estimates of methane emissions, the actual results were considerably lower than expected. Further, the levels observed during completions flowbacks are off by an astonishing 99%.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]To be specific, the EPA national greenhouse emission inventory theorized that the 8,077 well completions with hydraulic fracturing in 2011 produced 654 Gg per year of emission or 81 Mg of methane per well. The reason? As it turns out, the EPA estimated these GHG emissions using only engineering models and did not conduct on-site sampling.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]To get a more accurate inventory, researchers from the University of Texas at Austin Study used on-site measurements of methane emissions from natural gas production in shale production regions. Their findings were that each well produced an average of 1.7 Mg of methane per flowback operation. That’s a reduction of 79.3 Mg of methane from the EPA’s theoretical numbers.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]So why is there such a divide between the two studies? The EPA assumption model does not adequately account forgreener techniques, regulations or new technologies for controlling methane emissions. Researchers from the University of Texas at Austin observed 67% of wells sent methane to sales or to other control devices where 99% of potential emissions were captured or controlled through flaring. For the remaining wells, those allowed to vent methane directly into the atmosphere, the researchers identified this impact to be less than previously thought as well. Of the nine wells researchers observed, the average potential methane emission was “0.83 Mgm which is 0.55% of the average potential in the national inventory.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]To help comprehend the findings of the University of Texas at Austin’s study, let’s look at each of the GHG controls mentioned above a little closer.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]When natural gas is sent to sales it is separated from water as it returns to the surface and is then put into to a pipeline which will deliver it to end users. This method is the greenest technique for managing methane emissions since no GHG (carbon dioxide or methane) is being emitted while the well flows back. If a pipeline is not available to flow the gas to sales, the rising gas and water is separated and the gas is burned off in a controlled manner. Through combustion of natural gas, carbon dioxide (CO₂) and water vapor (H₂O) are created.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]For Cabot Oil & Gas Corporation, producing natural gas while protecting the environment is not mutually exclusive, especially when it comes to fugitive methane emissions and GHG. Since entering the Marcellus Shale play, Cabot has implemented a number of environmentally friendly controls in its operations including sending gas straight to sales and flaring when necessary.
[/vc_column_text][/vc_column][/vc_row][vc_row animation=””][vc_column width=”1/1″][vc_column_text]To read the University of Texas at Austin study in full, please click here.[/vc_column_text][/vc_column][/vc_row]