Table 1
The main characteristics of Elk City, Oklahoma; Conway-Yoder field, Kansas; Mt Belvieu, Texas; Mineola, Texas.
| Elk City, Oklahoma | Conway-Yoder field, Kansas | Mt Belvieu, Texas | Mineola, Texas | ||
|---|---|---|---|---|---|
| Cavern information | Commissioning | After 1954 | 600 caverns since 1951 | 1963 | End of 50’s |
| Incident date (1st noticed) | February 1973 | NGL detected in wells 1956–2012; Propane atmosphere eruptions June 30, 1980 | 9/17/1980 (pressure drop); gas burst on 10/3/1980 | 1995 | |
| Geology | Bedded salt Formation Blaine, alternating layers of salt, anhydrite, shale’s | Bedded salt tight overburden; located at a dissolution boundary | Domal salt Pervious Caprock Drill losses | Domal salt | |
| Stored product | LPG (mainly propane) | Propane, or LPG | Ethane, propane | Propane | |
| Last cemented casing shoe | 10¾″ at 410 m | ≈200 m | 8⅝ at 482 m | ||
| Penultimate cemented c.s. | 35.5 m | ||||
| Leak mechanism | Breach depth | Less than 365 m deep | Shallow? | ||
| Pressure drop | On 09/17/80 | ||||
| Mechanism | A breach somewhere between 365 m and 35.5 m, upward in the cement, horizontal in the Doxey Formation | Gas leaking from several faulty wells | The leak was likely to be at caprock depth | A breach in the casing originating from a pressure surge in a neighboring cavern | |
| Impact at the surface | Effects at ground level | 9 × 15 m, 6 m deep crater | Propane found in shallow wells | Explosion in a cellar, gas is found in shallow waters | Gas occurrences near the wellhead |
| Distance from wellhead | 700 m, 23 m below wellhead elevation | In a 30-m radius around the wellhead | |||
| Evacuation/Casualties | Several families relocated | 50 families evacuated | |||
| Emergency resp. & remediation | Measures taken | Soil gas sampling and analysis, storage emptied, CBL run | Analysis of geological data, Temperature logs, CBL, 8 monitoring wells drilled, 71 operating wells evaluated | Cavern emptied, wellbores tapped in the shallow aquifer layer to vent gas | Fire extinguished |
| Remediation | Water-filled annular space, packer set at 365 m | Brine wells abandoned |