Change From Permanent P&A to Temporary P&A

Dear Oilfield fellows,

We are drilling an offshore exploration well with a Jack-up Rig:

• Water depth = 103 ft,
• RKB to Mud Line = 207 ft,
• Casing design: 30" conductor, 20" conductor, 13 3/8" casing, 9 5/8" casing with 7" Liner,
• Wellhead starting from 13 3/8" with 9 5/8" casing string sits on the wellhead (no MLS - Mud Line Suspension),
• Four DST operations: 2 inside 7" Liner and 2 inside 9 5/8" casing.

Originally, we planned to permanent P&A the well after the four DST operations (cut casings below Mud Line and set surface cement plug).

However, due to the good DST performance, the plan changed and now we plan to put the well on temporary P&A so we can complete and put on production in near future. 

Has anyone had same experience with us? If so, how would you temporary P&A this well? If possible, can you share your temporary P&A program based on this scenario?

So far, we have two temporary P&A options in our mind:

1. Put wellhead cap and leave all casing strings free standing as they are now. This option shall give us the shortest operation time but the risk is that the casing stub above Mud Line may collapse.
2. Cut all casing strings in staggered from below to above mud line and in the future we will connect the casing back with Packer Type Casing Patch to surface. This option will consume more time but is a safer option.

Can anyone comment on the two options we have? Has anyone had experience with Packer Type Casing Patch previously? Specially for production casing string? 

Appreciate your inputs and comments. 

Regards,

Freddy M.

5 Answer(s)

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