A loss of well control (LOWC) is an uncontrolled flow of subterranean fluids (such as gas, oil and/or water) from a well to the environment. While a LOWC is considered highly unlikely due to Chevron’s comprehensive suite of preventative measures, potential effect pathways for different environmental receptors (e.g. species, habitats, socio-economic and heritage features) vary depending on the nature of the oil (on the sea surface or entrained and dissolved in the water column), the condition of the oil (fresh or weathered), the oil concentration, the location of receptors that may encounter the oil that is released (e.g. offshore, nearshore, onshore, etc.) and the sensitivity of the receptor to oil and duration of exposure to oil.
Fact sheets - Model inputs
Fact sheet - Determining the environment that might be affected
Fact sheet - Environmental thresholds
Fact sheet - Oil spill modelling outcomes
A vessel collision is considered unlikely due to the slow speeds at which project vessels will be moving in the area and the suite of control measures in place to reduce the risk, such as 24-hour bridge-watch, lighting and onboard navigational and warning systems on both the rig and support vessels. If a collision occurred, the subsequent probability of a moderate volume of marine diesel oil (MDO) being released is extremely low due to vessel tank design and onboard control options, such the ability to decant fuel from ruptured fuel tanks to other tanks, reducing the volume of MDO lost to the marine environment.
Fact sheet - vessel collision