Negative Operational LL with DNO

Oselvar (A-1 H, A-2 H, A-3 HT2) – N/A

What happened:

DONG handover documentation: Again challenges where seen due to backflow when RIH on DP / HWDP. Several stands and singles where run with the TDS made up to avoid backflow. Once sufficient solid pipe was in the hole a slug was pumped. This is however a bad practice as the slug in the pipe will result in inaccurate TT resonse.

External Actions

In future include a flapper valve in the running string. Either below hanger setting tool (just above bull nose) or above hanger setting tool. Discuss with BOT the best option to prevent hydr. lock of tools etc. This will require filling string, but is better than backflow challenges.