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Field: New development

Well: 2 oil producers and 2 injectors

Operation type: installing middle and upper completions

Reservoir: isolated by lower completion

Conditions: harsh to moderate

Location: Norwegian Sea

Rig: Deepsea Yantai (GM4D)

Case: dynamic rig heave limit calculated during well planning and utilized when installing middle and upper completion

“The simulations made by Heavelock Solutions were very beneficial to Neptune Energy`s completion operations on Fenja. They helped us to take decisions to start running completions even if the rig heave was above what was recommended by our completion vendor. Our vendor accepted the recommendations provided by Heavelock Solutions.”

- Steen Tino Svenningsen, Lead Completion Engineer

- Neptune Energy

Neptune Energy - Fenja


Completion operations on Fenja were planned to commence in December and concern for heave-induced surge and swab was flagged high in the risk register. Accurate weather criteria were deemed to be required to lower the operational risk and to optimize the uptime, i.e. to reduce Waiting on Weather (WOW) and hence also costs.


When running middle and upper completion with a production packer there is a risk of “lifting” the packer element and pre-setting the packer due to fast fluid bypass in the annulus around the packer element. Following risks related to surge and swab were identified:

•    Swabbing of the packer elements
•    Getting stuck
•    Pulling completion

Potential mitigation

There are a number of methods traditionally utilized to lower the risk of surge and swab. All of them either put a costly limit on the operations or require accurate information on how close to the packer limits you are at all times in the well - something Heavelock Solutions provided.

•    Running completions summertime
•    Limit number of packers
•    Run in very slow, abort if heave


Neptune Energy recognized that Heavelock Solutions had a very good business case - to utilize tailor-fit surge & swab simulations that would take into account rig heave motion, well trajectory, well fluids, weather data at location, completion components, casing and well geometry in order to determine true limits for rig heave throughout the operation.


Advanced surge & swab simulations provided a tailored and fit for purpose weather criteria that reduced risk for getting stuck, damaging the completion string as well as potential NPT related to WOW.  The simulations led to considerable cost reductions by reducing rig time.


For example, the WOW-related downtime was reduced by 6-8 hours for 1-AH producer well.


It was also considerably easier to find the weather window required to start the operation.

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