Technical Challenge no 6 : November 2001

Subject: Stuck pipe series No 2: Sandstone inter-beds

Mud Wt: 1.27 S.G.
Mud Type: KCL Polymer
Hole size: 17 1/2"
Well Profile: Vertical
Rig Type: Semi submersible
Water Depth: 1200m

The 17 1/2" hole section was drilled through a very inter-bedded sequence into a competent claystone at 1850m. The hole was circulated clean and the pipe pulled for logging. The 13 3/8" casing was run immediately after logging. The casing was run to 1830m and the cement stand was made up. This took approximately 40 minutes. Average casing running speed was 16 doubles per hour. Losses at 5-10bbls/hour were reported while running casing.

When continuing to run the string after installing the cement stand the casing was found to be stuck.

QUESTIONS

Q1: What caused the stuck pipe?
Q2: What measures should have been taken to avoid the incident?
Q3: What would be the most appropriate method of freeing the pipe in this situation?
Q4: What mud changes on future wells should be recommended to prevent reoccurrence?

Any feedback or comments please send to challenge@kingdomdrilling.co.uk

Challenge 6 : Stuck pipe series No 2: Sandstone inter-beds
November 2001 (68k) - Download PDF

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