Recently, KOC’s Burgan Field has encountered various challenges, particularly in water production. A notable increase in water cut across multiple wells is significantly impacting production—notably in BG-0432, which was nearing a 94% water cut. This well was extracting from nine perforated zones located between 4,136 ft and 4,576 ft.
The increase in water production within Burgan Field not only substantially impacts production rates and revenue but also demands the management and treatment of produced water. Consequently, this additional demand inevitably results in extra costs for KOC to ensure the appropriate treatment.
Seventy percent of KOC’s wells use artificial lift methods, often 9 5/8-in casing and conventional electrical submersible pumps with Y-tools for wireline intervention. These Y-tool completions frequently contain standard 2 7/8-in bypass tubing, which limits the options for isolation solutions.
The core objective of this operation was to prioritize cost effectiveness, striking a balance between the expenses associated with the zonal isolation platform and the potential benefits of increased hydrocarbon production and prolonged well lifespan.
The original design of the high-expansion cement platform necessitates two separate runs—one for anchor setting and another for the cement retainer. However, locating the anchor fishing neck within the 9 5/8-in casing, especially in deviated wells, poses a challenge. Collaboration between KOC and the SLB engineering team was required to upgrade the existing high-expansion system for single-run deployment to meet requirements.
The cement platform of the Hi-Ex™ high-expansion through-tubing tools was necessary to achieve a permanent zonal isolation in the well. The two-run system was redeveloped into a compact platform for deployment in a single run. The existing platform array was coupled to a new modular anchor section, with improvements also made with a crossflow snorkel. Minimizing the setting stroke to ensure compatibility and minimizing length and weight to enable the setting procedure were two critical requirements also met.
SLB recommended the Hi-Ex cement platform as a reliable, cost-effective, and simple-to-deploy zonal isolation solution that can be used without the need for a workover. Conveyed on standard slickline, digital slickline, or wireline in a single run, the Hi-Ex cement platorm’s slim design enables it to pass a restriction as narrow as 2.25 in and expand to set in up to 9 5/8-in casing.
A production logging tool (PLT) was employed to investigate the source of water. Analysis confirmed that water production mostly originated from the upper zones located at 4,136 ft, which determined the precise setting depth.
The Hi-Ex cement platform was successfully deployed on SLB wireline at 4,120 ft in BG-0432 to isolate the perforation zones. After the platform was set, 20 ft of cement was placed, and a pressure test was conducted. As a result, the main zone producing water was completely isolated without the need for a workover, allowing the reperforation of the well at multiple intervals.
After reperforation, the production rate surged 198% from 152 to 454 bbl/d while the water cut plummeted from approximately 94% to 0%.
This operation represents a significant milestone, and upon broader implementation, it revolutionizes KOC's workover planning. Many wells falling into this category will no longer require a workover rig, as a comprehensive rigless solution is now available.
