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doi:10.2204/iodp.sp.328.2010

Operations plan

Up to five pipe trips will be required to complete the following steps of the ACORK installation:

1. A jet-in test to determine the depth to set load-bearing conductor casing (tentative),

2. Conductor casing and reentry-cone installation,

3. Drilling to a total depth of 315 mbsf,

4. Installation of the ACORK casing string with operational wellhead pressure monitoring instrumentation,

5. Installation of a bridge plug, and

6. Deployment of a remotely operated vehicle (ROV)/submersible landing platform.

Details of the operations plan and a breakdown of time estimates are provided in Table T1.

Based on previous drilling experience at this location, it is anticipated that four joints of 16 inch conductor casing will be required. The 10¾ inch ACORK casing and its screens will be deployed in the open hole below this with the help of an underreamer, which will have been used during the previous expedition. The ACORK casing will hang in the 16 inch conductor casing from a landing flange at the base of the reentry cone. To maximize the hydraulic resistance between the uppermost screen and the seafloor, a swellable packer will be employed at the top of the ACORK casing string to seal the anulus between the 10¾ inch and 16 inch casings. The bottom-hole seal for the 10¾ inch ACORK casing has not yet been selected. Two possibilities are a mechanical-set bridge plug (rotationally or hydraulically activated) and a swellable packer (positively latched to withstand formation overpressure). Use of cement is also being considered to augment this critical seal.

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