First Sand Clean Out of a HPHT Well on the Norwegian Continental Shelf Using Rig Assisted Snubbing and Sand Cyclones

Abstract

The Kvitebjørn field is located in the Norwegian North Sea – production is based on gas/condensate bearing reservoir formations. The reservoir/field is classified as high pressure high temperature (HPHT). The main field development is centered on a steel jacket platform with combined production, drilling and quarters facilities (pictured). This paper will describe the background, planning, execution and results of a rig assisted snubbing (RAS) operation conducted to clean out the production liner in Kvitebjørn well A-9 T2. Intial production from well A-9 was significantly below expectations. At first this was attributed to complications related to a closed/stuck valve in the bottom of the completion string. A successful coiled tubing milling operation eventually removed the blockage caused by the valve but the poor production performance continued. It was concluded that wellbore fill in the production liner was blocking production and mechanical access to the reservoir section. Planning was initiated for a wellbore fill cleanout operation and rig assisted snubbing was selected for the task. To ensure a successful operation a number of significant challenges were overcome including limitations on available experience with the type of operation, availability of qualified equipment and logistics issues related to other on-going activities on the platform. Fluid management was also a major consideration for the planning/operations team. After an intensive planning period the operation was executed successfully in 2013 and the production liner in the well was cleaned out down to the reservoir section. Additional wireline conveyed perforating could then be performed. Despite these successful actions production from the well continues to fall below expecations and further remediation activites are being evaluated.