February 18, 2016
NOTICE IS HEREBY PROVIDED that the leaking well (SS25) at the Aliso Canyon Gas Storage Facility has been successfully sealed.
The Department of Conservation's Division of Oil, Gas and Geothermal Resources (Division) bases this determination on its review of the results of a battery of post-cementing tests conducted by the Southern California Gas Company (SoCalGas). These tests were conducted at the Division's direction and under the Division's supervision. Each test was witnessed by a Senior Oil and Gas Engineer from the Division. This set of confirmation tests was formulated in consultation with technical experts from the Lawrence Berkeley, Lawrence Livermore and Sandia National Laboratories. The tests measure specific criteria to determine if any gas is still leaking from the gas storage reservoir through the cement plug in SS25. The results of the tests, set forth below, indicate that the sealing of the well was successful.
Detailed descriptions of these tests can be found on the Department's website .
1. Temperature Log/Test
The results of this test were successful and indicate that there is no leak of gas around the cement seal in SS25. Had there been a defective cement plug, gas rising past the seal would expand and cool. The absence of cooling in the Temperature Log indicates that the cement sealed the leak. The test results can be found here aa SS25_2-16-16_Temperature_Noise_Log (PDF).
View log file printing information.
2. Noise Log/Test
The results of this test were successful and indicate that there is no sound of moving gas. Had there been a defective cement plug, the gas moving would have made noise as it migrated near the well bore. The test results can be found here
aa SS25_2-16-16_Temperature_Noise_Log (PDF).
View log file printing information
3. Fluid Level Monitoring
The results of this test were successful and indicate that fluid in the tubing is not leaking past the cement. Had the cement not sealed the well, fluid could have migrated down through or around the cement, causing the level of the fluid to drop. The plug was under more than 1,270 psi of pressure at the surface plus 2,480 psi of hydrostatic pressure on the cement in the tubing and the fluid level remained unchanged. The fluid level measurements can be found here
aa SS25_Fluid_ Levels (PDF).
Cement Bond Test/Log
The results of this test were successful. The results show that the cement in the annular space between the tubing and casing was placed appropriately to seal the well according to the plan and is completely bonded between those two metal barriers. Had there been an incomplete bond of cement to metal, the cement bond log would have identified it. The cement bond log can be found here
aa SS25_2-17-16_Cement_Bond_Log (PDF) and here
aa SS25 2_17_16 Cement Bond Log of 2.875x7 annular cement top (JPG).
View log file printing information
5. Positive Pressure Test
The results of this test were successful. After perforating four holes in the tubing below the level of the top of cement in the annular space, the cement in the tubing and in the annular space was positively pressure tested. The well held pressure at levels that indicate the cement is effectively sealing the well. The pressure readings for this test can be found here
aa SS25_2-17-16_Cement_Plug_Pressure_Test (PDF)
In addition to confirming the successful completion of the tests described above, the Department has consulted with the California Air Resources Board (ARB) regarding the measurement of methane emissions and air quality monitoring it has completed in conjunction with the South Coast Air Quality Management District. One primary purpose of this measurement and monitoring is to determine the reduction of gas at and around the SS25 site that is consistent with successful seal of the leak. ARB stated that:
"Measurements taken by ARB and its partners, including the South Coast Air Quality Management District, using air flights, on-site observations, and monitors in the Porter Ranch and surrounding communities after the leaking well was controlled on the morning of February 11 confirm that the leaking gas has diminished consistent with successfully controlling the leak. Criteria ARB developed in partnership with the South Coast Air Quality Management District support the finding that emissions are controlled and that air quality has returned to typical levels."