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doi:10.2204/iodp.sp.337.2010

Operational risk

Hydrocarbons

The drilling site is located near commercial gas production wells, but no evidence of overpressure was found at the offset well. The previous expedition showed that C₁/C₂ is >1000 without detection of >C₃ gas in the piston cores to 350 mbsf. The site is positioned within a basement syncline in an area where shallow hazards were considered minimal. Even if hydrocarbons would be encountered, mud weights can be increased to control possible flow from the formation during riser drilling.

Weather

Expedition 337 has been scheduled to take place during spring, when no typhoon or seasonal severe weather is expected. The drilling site is free from strong ocean current. In the case of extreme weather, we would evacuate after disconnecting the BOP. Reentry would be possible.

Contingency and alternate plan

Unforeseen circumstances could result in insufficient time being available to complete the entire operations plan. Examples include collapse of a borehole because of difficult formation conditions (unstable sands), hazardous weather, and hardware failures. In anticipation of challenging and fluctuating environmental conditions, we have included 8 days of contingency for the entire expedition in the operations plan and time estimate. In case further delay in operation takes place, we will adjust the time by reducing the number of spot cores.

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