CONFERENCE PROGRAM

摘要

Methanol is currently used to treat a tree/jumper and wellbore prior to well start up and at shutdown to prevent hydrate formation, in this example. Data collated over the years confirmed that the well could stay for about 2 -3 days without treatment with methanol after shutdown. Though during shutdown, the fluid temperature was in the hydrate zone, no plug was observed during restart of the wells. The explanation for this phenomenon was that there is segregation of the gas, oil, and water phases that prevent a full growth of hydrate plugs. It is found that methanol is only critical just prior to startup than at the beginning of shutdown. This results in significant reduction in methanol consumption should the no -touch time be extended (period of no well treatment with methanol or blowdown/ dead oil of the flowline after shutdown) from 3hrs to 24hrs. A field test with a production well was conducted to further validate the theory in 2015. The well was shut-in for 36hrs with the tree, jumper, and wellbore not treated with methanol. The well was restarted with methanol and there was no evidence of hydrate restriction or a plug. To ensure no agitation of fluid in the jumper for a shut-in well that is hooked up to a live flowline, it is required that the well selector valves be in closed position to ensure no live fluid ingress into the well jumper. This presentation will discuss the results of the field test.