Investigation is under way of an apparent release of hydrogen sulfide that is suspected of killing three service rig workers and injuring four others Aug. 10 in Rincon oil field near Ventura, Calif.
The unusual accident occurred while a service crew was converting a shut-in oil well to a water injection well. Determination of the cause of death is pending autopsy reports.
The three killed were employees of Pride Petroleum Services, Houston: Jason Hoskins, 22, Ventura; Sean Harris, 26, and Ronald Johnson, 24, both of Oxnard, Calif.
Of the four workers injured, two worked for Pride and two for Schlumberger Well Services.
The well is owned by Vintage Petroleum Co., Tulsa, on its Hobson lease next to the Highway 101 coastal freeway a few miles north of Ventura. It's part of a package of oil leases, mostly in the Ventura basin of Central California, that Vintage acquired from Santa Fe Energy Co. in December 1993. The properties include about 200 wells producing about 570 b/d of oil and 500 Mcfd of gas.
Oil fields in the Ventura basin mostly produce heavy crude, and occurrences of H2S in the area are rare.
"The confusing factor is we've never encountered any significant levels of H2S, and we've worked in that field for 20 years," said Mike Furrow, Pride vice-president and area manager.
WHAT HAPPENED
The crew was perforating the well, drilled in 1942 and shut-in since 1982, when water started flowing from a valve in the well cellar.
Although details of the incident await results of investigation, Furrow said he believes Hoskins leaned over at ground level to close the valve and was overcome, apparently by poisonous gas released with the water flow, and fell into the cellar. Johnson then jumped in to rescue him and collapsed.
It was not clear if Harris also tried to help or was near the edge of the cellar and fell in as a result of inhaling a toxic gas, Furrow said.
None of the workers was wearing gas masks because the operation was considered routine and there had been no previous reports of H2S leaks, said Pamela Morris, state Division of Oil and Gas representative.
The California Occupational Safety and Health Administration is investigating the accident, independent of probes by Vintage and Pride.
TRADING, PRECAUTIONS
All the crew members had been trained in dealing with H2S and recently attended a workshop on confined space rules detailing when to use gas masks, safety harnesses, and gas sensors.
Furrow said he believes Hoskins did not violate the rules, assuming he was at the cellar's edge, but contends his would-be rescuer should not have been so quick to jump in after him.
Hoskins' father, Cal, a Vintage employee, agreed, saying, "When the well blew, the situation should have been evaluated. Then the cellar should have been tested to see if it was safe to enter. Only then should someone have entered--with a harness."
Furrow said, "It appears to be such an isolated incident that it was unpredictable." But he added that industry in the area is likely to reevaluate safety procedures.
Pride since has installed gas monitors on all other wells in the area, he said.
Copyright 1994 Oil & Gas Journal. All Rights Reserved.
