Milling of Hard Scale One Week Faster than Alternative

Time was of the essence when an operator offshore Norway needed to remove scale on top of a downhole safety valve (DHSV). Welltec removed the scale in one week which was one week faster than broaching that was applied previously.

The DHSV had locked in the open position with no access from surface because of the scale that had settled on top of it. After two weeks of broaching, the well had been opened up to 4.6”. Due to pressing time issues coupled with very hard scale, the operator decided Welltec’s e-line scale milling solution was the better choice.

After four runs, the Well Miller had cleared the scale down to the DHSV, opening the well up to an ID of 4.7”. An attempt was made to pull the DHSV but the fishing neck was unable to be latched. The Well Miller was called into action again; this time fitted with a brush bit, and successfully cleaned the scale around the DHSV, allowing it to be retrieved. After Welltec had removed the scale, the client was able to pull the DHSV and replace it with a new one.

Client Quote
Onshore supervisor: “I would like to thank you and your team for the excellent effort so far. Although we have not yet retrieved the DHSV, the tractor/milling has performed beyond what I anticipated. Welltec mobilized for this job with very little advance notice and the support from the onshore staff in Tananger and Bergen has been first class. The equipment and contingency accessory items were called into action and performed well. You have set the standard for the future milling operations and expectations.”

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