Beyond the Headlines: Fugitive Gas and Flaring: Current and Future Realities
- Vikram Rao (Research Triangle Energy Consortium)
- Document ID
- Society of Petroleum Engineers
- Journal of Petroleum Technology
- Publication Date
- April 2016
- Document Type
- Journal Paper
- 16 - 19
- 2016. Copyright is retained by the author. This document is distributed by SPE with the permission of the author. Contact the author for permission to use material from this document.
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Beyond the Headlines
Are fugitive releases of natural gas and flaring environmental concerns? Can these be ameliorated today and even better in the future? Yes and yes.
A paper in 2011 by Howarth et al. suggested that fugitive methane emissions (releases directly to the atmosphere) from shale gas production amounted to 3.6% to 7.9% of all gas recovered and that those numbers were worse than coal. The authors took the comparison of greenhouse gas emissions to the precombustion stage. Since the dominant use of coal is for electricity production, post-combustion comparisons are merited. In so doing, natural gas is favored because power plants using natural gas are up to about 50% more efficient on conversion than coal plants.
Many of these original assumptions have been challenged and the data verified, most recently by an ongoing study by Allen et al. in a 2013 report in the Proceedings of the National Academy of Sciences. This Environmental Defense Fund-sponsored study reports that 0.42% of “the emissions are released” at the production site. The study is ongoing and more clarity is needed, especially regarding the locations and amounts of the releases. Since this and other studies were almost a direct consequence of the Howarth paper, much good came of that despite the justifiably disputed elements of the original work.
The principal reason for environmental concern about releases of methane is that it is a more powerful greenhouse gas than carbon dioxide (CO2). The potency numbers are somewhat in dispute and the general public may be confused. There is general agreement with the belief that methane is about 25 times more potent than CO2. The accompanying sidebar gives the science behind the calculation and explains why some believe it to be 72 times more potent.
The oil and gas industry continues to take steps to minimize methane release. Methane in the water flowing back from the well is usually separated, so collection is not an issue. If a pipeline is available, it is utilized. In the early days of a prospect there may not be an export line. In these cases, at the very least, the gas ought to be flared, thus reducing the potency of the released gas.
The inadvertent release of methane can come from hatches, gaskets, and the like that are not properly sealing. Also, in the distribution system, some valve systems operate using natural gas as the actuating fluid, and some release occurs each time they are operated. Alternative valve mechanisms are available, using compressed air, for example. Leaks are currently measured using infrared cameras. The ARPA-E Methane Observation Networks with Innovative Technology to Obtain Reductions (MONITOR) program is uniquely targeting innovative means for identifying methane leaks on the rigsite from a variety of sources. All of the foregoing ought to underline the fact that the industry is now fully aware of the issue and is getting its collective arms around solving the matter. Solutions are in the economic interests of the operators: gas that leaks away is gas that does not get sold.
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