During perforation preparations a well offshore Indonesia indicated a wellbore obstruction in the top of the existing producing zone. The wellbore ID was decreased to 3.37” and as the perforation gun’s possible swelling OD was up to 3.45” the operator needed to address the unknown obstruction.
Welltec provided a swift solution. The Well Tractor®, Well Stroker® and Well Miller® were mobilized with a variety of bit types and sizes to address contingencies. As the obstruction was first thought to be slightly damaged casing, the first run was made with an NPR bit to remove metal. However, recovered debris indicated scale build-up rather than damaged casing and the toolstring was reconfigured, ending up with a 3.7″ tapered scale removal bit and standoff.
Several runs were then made to accomplish the scale clean-out and once achieved a confirmation run was made with a 3.7″ scale removal bit, run in hole by gravity, which easily passed the problematic area, thus proving successful removal of the troublesome scale bridges.
Access to the perforation intervals had been restored and the perforation operation was then begun.
The operation provided faster access to increased production, which went from 1.5 mmscfd to 12 mmscfd, saving both time and the cost of mobilizing a CT unit: estimated at two weeks to arrive. It is testament to Welltec’s responsiveness and capabilities to deliver a viable solution when faced with an unknown well environment.
To learn more about the technology applied please view the Clean-out Solutions brochure or read the full case story Scale clean-out aids production through perforating accessibility.