RE: 12 hours of strong crude oil odour30 May 2023 17:59
Ocelot,
When you drill ahead and the cuttings bring back up some oil on them, that gets washed off the cuttings and into the mud system.
On a proper drilling operation, it gets screened out quickly.
However, in the surface set up that they have on Pin-1, it will be getting recycled and pumped around the Well again - possibly several times, smelling ach time.
Given how light it is claimed to be (API c. 41), it will evaporate quite quickly.
However, as IBug correctly stated, you can smell it at low concentrations, so it does tend to linger in the air.
How quickly it dissipates depends on a number of factors (e.g. wind, Day or Night, direct exposure to the Sun or cloud cover, temperature), so it's impossible to say how much meterage was drilled where there could have been some oil in the formation.
Apart from the fact that they didn't think it worth E-logging before they ran the 9 5/8" casing, one thing we do know for sure is that it's dead oil - it it was live oil, they'd have seen the gas bubbles in the returns.