First conveyance of perforation system offshore

Challenge
Conveyance
1036 X 518 JRU181494 First Conveyance Of Perforation System Offshore Min
  • Well type Injection
  • Depth 8,159 ft (2,487 m)
  • Temp. 176°F (80°C)
  • Pressure 165 bar
  • Max. deviation 90°

Background

In 2017, Welltec had carried out the conveyance of production logging tools in an offshore well for a Russian client. Two years later, based on well flow evaluation results, the client made the decision to convert the production well to injection, and isolate the water and gas intervals.

To achieve the isolation of the bottom interval, the client requested the setting of a bridge plug and the perforation of 58 meters of liner in the horizontal section.

In turn, this should increase oil recovery in the neighboring well and be the more economical option in comparison to a well kill and tubing conveyed perforating, which had also been considered.

Operation

The most effective method of conveyance for a bridge plug is via tractor, especially on an offshore platform.

With the perforation system being unique to the region, this job represented the first time that Welltec would convey a perforation gun with an inductor-based detonator on an offshore platform. Therefore, testing was essential in order to perform the operation.

A number of system integration tests (SIT) were carried out in order to establish the correct equipment and setup of the shooting panel, inductor-based detonator, wireline cable and 218 Well Tractor®. Following successful testing, equipment was mobilized.

Prior to perforation operations, cleaning was performed using the Well Cleaner® Reverse Circulating Bit (RCB (with brush)). Over six runs, the 218 Well Tractor successfully conveyed the 2” perforation guns to total depth (TD).

Achievements

The Welltec solution not only optimized well production, but also saved a significant amount of time, i.e. Wireline Intervention took five days, whereas a similar operation for a workover rig, with any alternative approach could be expected to take more than 10 days.

A fast response made this task feasible, and with the water producing interval isolated, the water cut was decreased and well production optimized.