By Kyle Ferrar, Western Program Coordinator, FracTracker Alliance
A natural gas well equipment failure in southern California has resulted in the largest point release of methane to the atmosphere in U.S. history. California Governor Jerry Brown has declared a California state of emergency for the incident, and the California Air Resources Board (CARB) has identified the site as the single largest source point of global warming.1 Since October 23, 2015 the failure has been reported to be releasing 62 million cubic feet of methane per day – 110,000 pounds per hour – for a total of about 80 million metric tons thus far. (A running counter for the natural gas leak can be found here, on Mother Jones).2,3 This quantity amounts to a quarter of California’s total methane emissions, and the impact to the climate is calculated to be the equivalent of the operation of 7 million cars.
SoCalGas (a subsidiary of Sempra Energy) reports that nothing can be done to stop or reduce the leak until February or March of 2016. As a result, the nearby community of Porter Ranch has been largely evacuated (30,000 people) due to health complaints and the rotten egg smell of tertbutyl mercaptan and tetradydrothiophen. Air quality sampling, being assessed by the Office of Environmental Health Hazard and Assessment (OEHHA), measured volatile organic compounds, specifically the carcinogen benzene, at concentrations below acute toxicity health standards.4 Exposure to benzene even at low levels presents a risk of cancer and other health hazards. Locals have complained of headaches, sore throats, nosebleeds and nausea. The LA County Department of Public Health has ordered SoCalGas to offer free temporary relocation to any area residents affected. About 1,000 people are suing the company.5 A fly over of the site has been posted to youtube by the Environmental Defense Fund, and can be seen here. The video uses a FLIR camera to take infrared video that shows the leak.
Figure 1. California active natural gas storage fields most active in 2014
The source of the leak is a natural gas storage well operated by SoCalGas in the Aliso Canyon oil field – a drained oil field now used to store natural gas. SoCalGas is the largest natural gas utility in the U.S., distributing natural gas to 20.9 million.4 Aliso Canyon is the largest gas storage field in the state, but there are numerous other gas storage fields in the state that could present similar risks. In Figure 1, to the right, California’s other currently active gas storage fields are shown. Injection volumes of natural gas are summed and averaged over the area of the field, and the Aliso Canyon is shown to have injected over 1,000,000 cubic feet per km2 of natural gas since the beginning of 2014. Other high volume fields include Honor Rancho, McDonald Island Gas, and Wild Goose Gas.
The failed well, known as Standard Sesnon 25, is marked with a red star in the map of gas storage wells shown below (Figure 2). The well was drilled in October of 1953. Reports show that pressures in the well bored reached 2,516 PSI in 2015. If you use the map to navigate around the state of California, it is clear that there are numerous other natural gas storage facilities in California, with wellbore pressures similar to or higher than the reported pressure of Standard Sesnon 25 and other wells in the Aliso Canyon Field. Beyond California, the state of Michigan is reported to have the most natural gas storage by volume, at 1.1 trillion cubic feet.6 The incident that caused the leak was a well casing failure, although the cause of the well casing failure has not yet been identified. There have been numerous editorials written that have painted SoCalGas as a model for contemporary corporate greed and corruption for several reasons, including the removal of safety valves, reports of corrosion, and lack of resources for inspections and repairs.7 Rather than this being a unique case of criminal neglect, casing failures are a statistical likelihood for wells of this age. Well casing failures are a systemic issue of all oil and gas development. Every well casing has a shelf life and will fail eventually.8 Additionally, leaks from gas storage wells have occurred at other SoCalGas natural gas storage facilities in California, such as Montebello and Playa Del Rey.
Figure 2. California’s gas storage wells. The size of orange markers indicates wellhead pressure, as reported in 2015. Blue markers show the volume of gas injected in 2014/2015. The Aliso Canyon leak at ‘Standard Sesnon 25’ natural gas storage well is marked with a red star. Click here to manipulate the map. After expanded, use the “Layers” menu to visualize the data with colored markers rather than size.
Fixing the problem is therefore much more complicated, overall, in this specific case. Since the well casing has ruptured deep underground, natural gas is leaking in the annular space outside the borehole and spewing from the topsoil surrounding the well head. To stop the leak the production pipe must be plugged below the rupture. All attempts to plug the well from the surface have failed due to the high pressure within the borehole, a 7” inner diameter of the production pipe. Therefore, a relief well is being drilled to intersect the well casing, to inject a mud-chemical cocktail intended to plug the well far below the casing failure. Updates on the response, claims information, and the location of the Community Resource Center can be found here. Additionally, Governor Jerry Brown has declared a state of emergency, which means federal support and a requirement of the state of California to cover the costs.9
The state response to the natural gas leak has included numerous agencies. According to documents from California Public Utilities Commission (CPUC), the agencies leading the response are the California Department of Conservation, Division of Oil, Gas, and Geothermal Resources (DOGGR), the Office of Emergency Services (CalOES), California Air Resources Board (ARB), California Division of Occupational Safety and Health (CalOSHA), the California Energy Commission (CEC), and the CPUC. DOGGR is conducting an independent investigation of the incident. The investigation will include a third party analysis for root-cause issues. CARB is monitoring total methane emissions while the Office of Environmental Health Hazard Assessment with CalEPA are collecting and reviewing air quality data. Coordinated response information can be found on the CalOES site. SoCalGas has submitted a proposal to regulators to raise customer rates in order to raise $30 million for a more proactive approach to inspections and repairs.10
This event is the largest, but is not the first major methane/natural gas leak to occur at a wellsite. Leaks can result from a number of natural and anthropogenic (man made) causes. Besides the natural degradation of well integrity with age, acute events can also cause casing failures. There are documented cases where seismic activity has caused casing failures.
As a result of an earthquake natural fractures in the region can grow and disrupt well bores. In areas of dense drilling, fracture stimulations that propagate improperly or intersect unknown faults. When two wells become interconnected, known as “downhole communication” or a “frack hit” when it occurs due to hydraulic fracturing, spills and leaks can occur due to over-pressurization. In many states, these risks are mitigated by having setbacks between wells. California, the most seismically active state, has minimal setbacks for drilling or fracking oil and gas wells. In previous research, FracTracker found that over 96% of new hydraulic fractures in 2013 were drilled within 1,200 feet of another well, which would even violate setback rules in Texas!
Natural gas is hailed by the fossil fuel industry as the bridge fuel that will allow the world to transition to renewables. The main argument claims natural gas is necessary to replace coal as our main source of generating electricity. Burning both coal and natural gas produce carbon dioxide, but natural gas is more efficient. For the same amount of energy production, natural gas produces half as much carbon dioxide emissions. The legitimate threat of climate impacts comes from fugitive (leaked) emissions of methane, before the natural gas can be burned. Since methane is a gas, it is much harder to contain than oil or coal. Methane is also more insulating than carbon dioxide in the atmosphere (34-86 times more insulating), making it a more potent greenhouse gas. The leaked natural gas from the Aliso Canyon well is currently equivalent to 7,000,000 tons of CO2 (Updated here, on Mother Jones).
Current estimates show methane is responsible for 25% of the world’s anthropogenic warming to date. Proponents of the bridge fuel theorize that if methane leakage can be kept under 4% of total production, natural gas power generation will provide a climate-positive alternative to coal. EPA estimates set the leakage rate at 2.4%, but independent research estimates actual rates up to 7.9%.11 The EDF has been conducting an $18 million project focused on quantifying methane leaks from the natural gas industry. A team of 20 researchers from 13 institutions conducted the 2 year study measuring emissions from the Barnett Shale. Details can be found on the Environmental Defense Fund’s Page.12
Natural Gas Leak References
- Goldenberg, S. (2016). A single gas well leak is California’s biggest contributor to climate change. The Guardian. Accessed 1/6/16.
- Environmental Defense Fund. (2015). Aerial Footage of Aliso Canyon Natural Gas Leak. via YouTube. Accessed 1/5/16.
- Lurie, J. (2016). Thousands of Californians are Fleeing an Enormous Methane Leak. Here are 8 Things You Need to Know. Mother Jones. Accessed 1/6/16.
- CalOES. (2015). Aliso Canyon Natural Gas Leak. Accessed 1/8/15.
- BBC. (2015). California state of emergency over methane leak. Accessed 1/8/15
- Ellison, G. (2015). Michigan has most underground natural gas storage in U.S. MLive. Accessed 1/8/15.
- Reicher, M. (2015). SocalGas knew of corrosion at Porter Ranch gas facility, doc shows. LA Daily News. Accessed 1/5/16.
- Ingraffea et al. (2013). Assessment and risk analysis of casing and cement impairment in oil and gas wells in Pennsylvania, 2000-2012. PNAS. Vol.111 no.30.
- Cronin, M. (2015). Why Engineers Can’t Stop Los Angeles’ Enormous Methane Leak. Accessed 1/4/16.
- CUUC. (2015). Appendix A. Accessed 1/5/15. [please note that some CPUC files are being taken offline for unknown reasons]
- Howarth et al. (2011). Methane and the greenhouse-gas footprint of natural gas from shale formations. Climatic Change. 106:679-690.
- Song, L. (2015). Texas Fracking Zone Emits 90% More Methane Than EPA Estimated. InsideClimate News.
Feature Image: Aliso Canyon natural gas leak – Photo by Environmental Defense Fund