Plug and abandonment solution streamlined decommissioning job
An operator in Norway needed to permanently plug and abandon (P&A) a large field development with five wells located at 984-ft (300-m) water depth. The scope and difficulty of the project were considerable, so the operator contacted Baker Hughes, a GE company (BHGE), seeking an integrated approach.
The field was developed to provide gas and increase production to another field in the North Sea. The development was eventually closed down and temporarily abandoned. The scope of work for the P&A was to establish a deep well barrier, followed by cut and pull of the 95 /8-in. and 133 /8-in. casing, 183 /4-in. wellhead, 30-in. conductor, 42-in. washout sleeve; all wells needed to be disconnected from subsea template by cuts 16.4 ft (5 m) below the seabed.
After carefully reviewing the job details and developing a detailed plan of execution, we deployed our experienced teams to provide a coordinated effort that included cementing services, fluids, mud logging, milling, cutting, and fishing services.
First, the five wells were temporarily abandoned using a light well intervention (LWI) vessel, and all subsea trees were removed before the rig arrived. Once the rig was in place, the completion was pulled and logging tools were run on wireline to find the correct placement for the barrier and to identify gas below casing hanger. Cement plugs were then placed inside the 95 /8-in. casing, and the casing was cut and successfully removed using a Model B™ spear.
Before the casing hanger could be removed, the seal assembly needed to be milled. To enhance efficiency, BHGE used a specialized 185 /8-in METAL MUNCHER™ Advanced Milling Technology (AMT) junk mill. A cement plug was then set inside the 133 /8-in. casing, and it was cut and pulled using a Model B spear. The seal assembly was milled using our METAL MUNCHER AMT mill, similar to the way it was used with the 95 /8-in. seal assembly.
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- Offshore Norway P&A operation
- Subsea template with six slots and five wells drilled
- More than 10 years after initial drilling, field was shut down and wells were secured temporarily
- Wells located in 984-ft (300-meter) water depth
- Needed to cut and pull 95 /8-in. and 133 /8-in. casing, 183 /4-in. wellhead, 30-in. conductor, and 42-in. washout sleeve
- Job required nonstandard products such as large-size cement mills, casing cutter, and casing spear
- Enhanced operational efficiency with a fully integrated solution
- Minimized the number of trips needed
- Reached 99.62% uptime