Regulators, environmentalists and operators are focused more than ever on well integrity as the three-month-old battle to plug a natural gas storage well leak in Southern California forces stakeholders to find a way to prevent similar incidents.
In that regard, 18 wells have been at least temporarily taken out of service by Southern California Gas Co. (SoCalGas). SoCalGas on Wednesday rejected reports that it had decided to permanently close the 18 wells at its 86 Bcf capacity Aliso Canyon underground storage field. The Environmental Defense Fund (EDF) on Thursday called for state regulators to enact more comprehensive well integrity programs at the state's 12 storage facilities, which represent 343 active wells and nearly 350 Bcf of capacity.
Responding to reports in local news media, SoCalGas said it has not decided to shut 18 additional Aliso Canyon wells, all of which have been identified as top priority for inspections that require the temporary plugging of each well.
"Once an inspection is completed, an assessment will be made on future courses of action [on each well], including a determination if the well is safe to put back into service," a SoCalGas spokesperson said.
Separately, the state Senate on Thursday unanimously passed urgency legislation (SB 380) to place a moratorium on operations at Aliso Canyon until all of its 115 storage wells have been inspected, tested and cleared for operation by the state Division of Oil, Gas and Geothermal Resources (DOGGR). SB 380 now goes to the lower house Assembly for consideration. A SoCalGas spokesperson reiterated that injections have been halted since October. Earlier, the California Public Utilities Commission ordered all storage wells in the state to be inspected.
In a request several years ago to state regulators for authority to use ratepayer funds to pay for a "storage integrity management program,” SoCalGas said its practices were focused on fixing leaks, not preventing them, and asked regulators for approval of "a more proactive and in-depth approach [see Daily GPI, Nov. 18, 2013]."
Examples of the reactive type of maintenance of the gas storage wells were cited recently in a state legislative committee briefing paper. It said that in 2008 SoCalGas discovered an over-pressurized well at Aliso Canyon (Porter 50A). "In most cases, situations like this can be indicative of production casing leaks from either internal or external corrosion," according to the paper, which was written by an Assembly Utilities and Commerce Committee staff member.
"High-pressure gas can migrate to the surface in a matter of hours. External corrosion also has been observed in other wells at [Aliso]," said the legislative staff report, which also cited a 2013 incident where production casing well leaks were found in two wells adjacent to shallower oil production sands, giving no evidence of leaks at the surface.
"Routine surveillance and temperature survey work identifies problems that have already occurred, and well integrity may have already been severely compromised requiring immediate attention to maintain safety, integrity and reliability."
EDF called the recently released draft emergency regulations from the state's DOGGR "an important first step," but it reiterated that emergency measures won't resolve the issues inherent in the complex leak of the Aliso well (SS-25).
"[Emergency rules] must be the beginning of a long, continual effort to upgrade gas storage regulations, especially those relating to well integrity," wrote EDF's Scott Anderson on his organization's Energy Exchange blog. "Thankfully, leaks the size and duration of SS25 at Aliso Canyon are rare."
(The latest statistics from the periodic aerial surveys over the SoCalGas leak site from the state indicated a slight uptick of leaking volumes on Tuesday to 20,700 kilograms of methane/hour (kgm/h), compared to 19,600 kgm/h five days earlier. The estimated total volumes that have escaped since Oct. 23 are now more than 5 Bcf, according to the rough state estimates.)
EDF said it hopes to work with California officials and stakeholders to "resolve well integrity issues and all other aspects of the methane emissions challenge." Anderson said the organization has been working on the issues for years, citing Texas and Ohio for updating some of their integrity requirements, such as cementing practices and pressure management in Texas.