Scale up to 1.5 inches thick blocked access through a UK North Sea Christmas tree. Downward pulsing cleared it with no risk to the wellhead, saving five days over pumping chemicals.
1.5-inch scale cleared from a Christmas tree
Scale up to 1.5 inches thick blocked access through a UK North Sea Christmas tree. Downward pulsing cleared it with no risk to the wellhead, saving five days over pumping chemicals.
Key results
- 1.5 inch thick scale removed
- Faster Treatment 5 days saved vs pumping chemicals
- Safe Treatment No risk of damage or tools being stuck
- Downwards Pulsing Radial pulses worked below the BlueSpark tool to gain access
Challenge
A major operator in the UK North Sea could not gain access to the wellbore of a producing well due to scale build up in the wellhead “Christmas Tree” (XT), confirmed visually by camera. They were looking for a treatment method that could effectively remove the scale without damaging any components of the wellhead.
- Depth: 35 m (120 ft)
- Temperature: 10 °C (50 °F)
- Treated Sea Water/TEG in wellbore
- Calcium Carbonate (CaCO3) scale
Solution
Remove scale by pulsing downward using electro-hydraulic pulsing technology
- The BLUESPARK® 275 tool was run in on 3rd party wireline
- Heavy scale (~1.5” thick) was encountered in various sections of the XT
- Several runs were made to clear scale from the swab valve down past the Lower Master Valve (LMV)
- A camera was run post-treatment to confirm the scale removal and the condition of the XT
Outcome
- Up to 1.5” thick scale was removed over the treated intervals, as confirmed by camera images
- Scale was removed, and the customer now had access through the XT into the main wellbore.