Uncertainty returns to timing of Aliso restart

OREANDA-NEWS. October 13, 2016.  California regulators cut by half the amount of natural gas that SoCal Gas must be able to withdraw from its Aliso Canyon underground storage field as a way to allow the utility to accelerate testing of remaining wells at the facility near Los Angeles.

As winter approaches bringing increased demand for gas, SoCal Gas is working to return the 86 Bcf (2.4bn m?) storage field to partial service nearly one year after a massive leak allowed 5 Bcf to escape over a four-month period. The leak prompted the relocation of thousands of nearby residents and led to stricter regulation affecting all storage operators in the state.

The question of whether and when Aliso Canyon returns to service and at what capacity remains.

The California Public Utilities Commission (PUC) recently pared the minimum Aliso Canyon withdrawal capacity by 51pc to 207mn cf/d, down from 420mn cf/d over the summer. To meet the earlier requirement, SoCal kept 17 partially tested wells available for withdrawal while the remaining 114 wells moved to advanced tests or were isolated from the Aliso Canyon reservoir.

As more wells passed the full battery of tests overseen by the California Department of Conservation's division of oil, gas and geothermal resources (DOGGR), SoCal conducted flow tests to better estimate how long it would take for approved wells to meet the summer withdrawal rate.

Using fully tested wells reconfigured to flow gas only in the inner tubing of the well would have taken "well into the winter" to meet the 420mn cf/d withdrawal rate, said SoCal vice president of transmission and storage Rodger Schwecke.

A lower required withdrawal capacity "means that fewer wells must be kept ready for withdrawal, and may assist SoCalGas in more quickly completing the state-mandated comprehensive safety review and safely resume injection operations at the facility," SoCal said.

Schwecke told state regulators in late August that the pipeline company might ask DOGGR for authority to inject gas into the field by early October, but that did not occur. Schwecke said that the projection was based on SoCal receiving approval to lower the withdrawal requirement earlier than it did.

SoCal officials are now cautious not to forecast when the request to restart the field will happen. "Our focus is on safely completing the review process in compliance with all regulations and state laws — not to meet a specific date," said SoCal Gas spokeswoman Melissa Bailey.

Staff of the California Independent System Operator (ISO) said the expectation is "that the Aliso Canyon facility will not be operational during the bulk of 2017."

California regulators let the October date pass without comment.

When asked, PUC and California Energy Commission officials deferred comment to DOGGR.

The agency is "focused on the viability of the wells, not the supply issue," said California Department of Conservation spokesman Don Drysdale. "Our concentration is on ensuring that the wells are all fully tested, as required, rather than on the timeline for doing that work."

The DOGGR website shows 27 Aliso wells have passed all tests, 78 are currently out of operation and test results for nine wells are pending.

Schwecke said flow test results on the reconfigured wells have "varied widely," in part because low reservoir pressure makes it difficult to remove fluids used during testing. "There is not a pattern whatsoever in how the wells are acting," said Schwecke.

He said flow tests confirmed that SoCal met the 420mn cf/d requirement, but how much gas will be needed for withdrawals this winter has yet to be determined.

A 28 June report from the PUC staff indicated that as many as 36 reconfigured wells might be needed to meet the 420mn cf/d target. The same report included a scenario that would require as much as 1.1 Bcf/d of emergency withdrawal capacity from Aliso Canyon, or 60pc of its pre-leak capacity, under extreme planned and unplanned events to avoid electric outages. With only 15 Bcf in remaining working gas, the report said Aliso Canyon would be unable to support such a high withdrawal rate until injections resume.

Schwecke said an internal pipeline corrosion assessment recently ordered by the PUC should not delay the ongoing safety review.