Any thoughts on why a closed in subsea well would see a rise in annulus pressure. The Well has been closed in for 10 days and a small rise is evident each day. Other than temperature I can't think why this would be the case.
If you've been pulling oil/gas out before it was closed, the pressure at the bottom of the well was reduced to below "formation pressure". That was what was driving flow from the formation into the well's riser. Now you've closed the well, so the reduced pressure is rebuilding up to formation pressure as oil/gas within the formation is still slowly moving to the riser. The rate of increase in daily pressure should slow and level off when well pressure equals formation pressure again. The amount of time it takes to do that is an indicator of formation permeability and sustainable production rate.
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