For the Standard Sesnon 25 well top kill, kill fluid (brown) has to build up in the casing and overcome gas (blue) flowing out of the sliding sleeve valves (LBNL 2016).
Selected by the U.S. Department of Energy, Office of Fossil Energy, Berkeley along with three other National Laboratories (Sandia, Livermore, and National Energy Technologies) co-chaired a Workshop on “Well Integrity for Natural Gas Storage in Depleted Reservoirs and Aquifers”. The workshop was held in Denver, Colorado this past July and was hosted by the four National Laboratories in response to the recent Aliso Canyon Natural Gas Storage facility incident, which occurred in October 2015.
The objective of workshop was to assemble gas storage operators, state and federal regulators, and technical experts to examine the current state of wellbore integrity in natural gas storage, including technology that can be used to ensure safety and to consider ways to reduce the possibility of future subsurface containment failure. The workshop also served as a forum where participants could share lessons learned and develop a common ground of understanding amongst regulatory issues and industry best practices.
Berkeley Lab’s Barry Freifeld (a scientist in the Energy Geosciences Division) states that, “there are approximately 400 gas storage fields in the United States with approximately 17,500 wells. Many of these wells are sixty or seventy years old, and were designed originally to produce oil and gas and not specifically for their current purpose of gas storage.” In response to the current state of natural gas storage, the four National Labs are also participating in the Interstate Oil and Gas Compact Commission drafting of a primer to help guide state regulatory agencies in gas storage field oversight.
Stephen Bauer from Sandia National Lab presented an overview of the Lab Team support to the State of California in responding to the Aliso Canyon event. Lehua Pan (Berkeley Lab) presented a poster detailing the computational tools developed to simulate the well control effort. The Lab Team support to the State of California, California Department of Conservation-Division of Oil, Gas, and Geothermal Resources included reviewing and consulting on California emergency regulations, reviewing confirmations of well sealing, of investigation plans, and of restart procedures for Aliso Canyon, and providing updates and presentations, and more. The capability of the Lab Team in developing and analyzing computer models of top kill and relief well operations buttressed the State’s decision making in responding to the event. (Berkeley Lab’s team participants included Barry Freifeld, Curtis Oldenburg, Lehua Pan, and Preston Jordan—all of whom provided crucial expertise in the areas of well engineering and operations, review of Aliso Canyon field operations, and modeling of wellbore flow and the efforts to control the Standard Sesnon 25 well.)
Following the Aliso Canyon incident, there was acknowledgment by regulators and operators that gas storage well engineering and operating practices needed to be revisited. The multi-Lab research team’s first order of business was to host the Well Integrity in Natural Gas Storage Workshop to foster a dialog amongst all stakeholders, guided by the best technical information available. The Lab Team is now preparing a report for the DOE, which will be made available to the public. This report will include an analysis of the Aliso Canyon event and surrounding circumstances, an evaluation of potential for problems at other storage sites, and provide recommendations for ensuring safe gas storage in the future.
The workshop website with general information can be found by clicking here along with a link to the workshop agenda and presentations.