The U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) (Berkeley, California) has been awarded $4.6 million by the California Energy Commission (Sacramento, California) for two projects aimed at improving the safety and reliability of the state’s natural gas system.
The first project, led by Yingqi Zhang, will receive $3 million to develop a more comprehensive approach toward risk management based on the integration of real-time data and scientific models. The second project, led by Jonny Rutqvist, will receive $1.6 million to develop a new three-dimensional (3D) methodology to identify and monitor areas at high risk of ground deformation caused by sinking land.
“California’s natural gas wells and pipelines face risks that could cause potential damage or catastrophic events,” says Zhang, a hydrogeologist. “There is an urgent need for a risk management system that is thorough, robust, and reliable and that will facilitate early damage detection and leak prevention.”
Both Zhang and Rutqvist are scientists in Berkeley Lab’s earth and environmental sciences section. Zhang will lead a multidisciplinary team of scientists who will develop and demonstrate a system aimed at helping facility operators and risk managers characterize, model, and manage the safety and integrity of underground gas storage infrastructure.
Scientific Models to Manage Risk
California has 14 underground storage facilities in 12 fields with a capacity of 385 billion ft3 of natural gas. There are about 350 active wells at those fields, many of which are used currently for natural gas but were designed for oil and gas production and constructed prior to 1970. In addition to leaks through wells, earthquakes, landslides, and caprock fracturing could also cause potential damage to natural gas storage facilities and possible natural gas leakage, the researchers explain.
“The way these wells were constructed decades ago may not be adequate for today’s standards,” says Zhang, who leads the first project. “The stresses they encounter today when used for natural gas injection and withdrawal were not considered during the original well design process.”
Zhang’s system—dubbed the Integrated Risk Management and Decision-Support System (IRMDSS)—will merge advanced monitoring technologies with scientific models to continuously assess risks and provide early leakage detection. The system aims to also identify potential threats to the system, assist facility operators with managing data and analyzing trends, and eventually help them evaluate options aimed at preventing leaks or mitigating risks.
In other words, IRMDSS will be designed to enable operators to be more proactive in taking preventive measures early on, instead of fixing a problem after it occurs, Zhang explains. “Compared to current risk analysis methods, IRMDSS provides a more quantitative, forward-looking analysis with advanced technologies,” she says. “We plan to incorporate real-time data to update our model and update our predictions.”
As an official partner, the Southern California Gas (SoCalGas) (Los Angeles, California) utility will work with the team to test and demonstrate IRMDSS at one of its underground natural gas storage facilities.
Drought Leads to Ground Deformation
A recent extreme drought in California led to large increases in groundwater pumping, which has resulted in unprecedented rates of subsidence. Pacific Gas and Electric Co. (PG&E) (San Francisco) has said about 50 mi of its natural gas pipelines could be affected by sinking land.
California currently imports about 90% of its natural gas, and climate change is expected to further increase the state’s reliance on groundwater, according to the Berkeley Lab scientists. “A fundamental understanding and evaluation of possible impacts on natural gas transmission lines are critical for risk assessment and monitoring,” says Rutqvist, who leads the second project.
On this project, Berkeley Lab and InfraTerra Inc. (San Francisco, California), in collaboration with the U.S. Jet Propulsion Laboratory (Pasadena, California), PG&E, and Natural Resources Canada (Ottawa, Ontario, Canada), plan to develop a new methodology that combines large-scale remote sensing surveys linked with advanced modeling and inverse analysis of ground deformation. A key advancement of this technology is to consider full 3D ground deformations and their impact on pipelines, the scientists say, including both horizontal and vertical components of surface deformation.
Surface deformation maps will be integrated with geological, hydrological, and engineering data on the natural gas infrastructure using a geographical information system (GIS).
“We’ll combine all this analysis and try to come up with a predictive methodology to forecast the risk to the natural gas infrastructure posed by future drought-related subsidence scenarios,” Rutqvist says.
Both projects aim to lower costs, boost system reliability, and to minimize methane leaks.
“Our team has a lot of expertise in advanced monitoring technology and modeling,” says Zhang. “It’s very exciting that we can use our knowledge to address a real problem. We expect that application of our system will result in lowered mitigation costs—and prevent disruptions to our energy supply.”