CHALLENGE
During a routine test, a major operator in the Danish North Sea determined that a Sub-surface Safety Valve (SSSV) of a well on an offshore platform would not successfully perform a routine inflow pressure test. The operator believed this was due to scale buildup in the upper completion.
Two separate interventions were attempted using conventional chemical and mechanical methods, but these failed to re-activate the SSSV. The operator had heard about electro-hydraulic stimulation (EHS), which can break up scale using shock waves and pressure pulses. The operator decided to mobilize Blue Spark’s WASP® technology, with its ability to remove scale from complex downhole completion equipment items, without risking any damage to them.
It was also decided to acquire a multi-fingered caliper log through a section of tubing to confirm the build-up of scale, then treat that scale, and lastly run the calipers again after the WASP® treatment to validate the removal of scale.
The post-treatment caliper log was then acquired, confirming that the scale was removed from the tubing (see figure at right). The scale was approximately 0.36 inches thick.
OUTCOME
- The WASP® tool is efficient to operate as it is deployed using a standard mono-conductor wireline unit. The treatment replaced either multiple slickline runs or a coiled tubing operation.
- The treatment was completed in less than 15 hours total operating time, while strictly following all normal protocols. The technology allows for the treatment of multiple intervals on the same run in the hole, further increasing efficiency.
- The technology is ideally suited for small footprint platforms and does not require an excessive amount of rig-up height or unusual lifting capability.
- The technology requires no chemicals, explosives or controlled goods, and as such is environmentally friendly and extremely safe.
- The technology was proven to be a very cost-effective solution to remove scale inside any completion equipment, including tubing, Subsurface Safety Valves, Side Pocket Mandrels, and Gas Lift Valves.
