US independent Walter Oil & Gas was operating the 250-foot mat-supported rig South Timbalier Block 220 in the Gulf when it lost control of a gas well on Tuesday morning. A cloud of gas vapour caught fire after dark and a section of the rig collapsed on Wednesday morning.
Forty-four people were evacuated and there were no injuries reported.
Hercules said its inspection revealed debris near the well site. US regulators and officials of Walter and Hercules are continuing to assess any potential environmental damage, Hercules said.
Hercules said it has contracted an outside environmental expert to monitor currents, wind direction and wave height "for the potential trajectory of any conceivable environmental spill".
Walter has hired Wild Well Control to help regain control of the gas well. Among the options are drilling a relief well, in which case Hercules plans to "promptly" mobilise the Hercules 200, a 200-foot mat-supported cantilever unit, to start drilling.
Separately, recent comments made by Hercules executive vice president Jim Noe which were critical of federal regulatory oversight of offshore drillers are getting renewed scrutiny in the wake of the latest blowout.
The Houston Chronicle dug up a quote made in April by Noe, who is also the executive director of the Shallow Water Energy Security Coalition, an advocacy group comprising E&P companies, drillers and service firms that was formed in the wake of the post-Macondo deep-water drilling moratorium.
“Ramping up the issuance of incidents of non-compliance for often trivial infractions is no substitute for technically substantive oversight – and threatens to take our eye off the ball on what is really important: what’s going on at the drill floor and in the well,” the group said three months ago.
Noe clarified the statements in a follow-up interview with the Chronicle on Wednesday, saying "the underlying rationale for regulating Gulf energy activity has never been questioned".
However, Democratic Senator Ed Markey said the latest incident suggests more oversight is needed.
“A new drilling well blowout in the Gulf of Mexico is raising continued questions about whether offshore drilling safety has improved, and whether new measures are needed to hold drilling companies accountable for natural gas leaks,” he said in a statement.