An onshore operator in Thailand faced the challenges of placing bridge plug and perforations with 2-m accuracy in a horizontal multi-stage interval prior to a fracturing operation and efficiently cleaning out the sand from the wellbore after fracturing. The solution selected to solve these two challenges was a fiber-optic-enabled coiled tubing (CT) string to support real-time plug set / perforation accuracy and sand cleanout, the first of this kind of operation in the Asia-Pacific region.

A fiber-optic cable was carefully pre-installed for slack management inside the CT string before the CT was stabbed into the well. The fiber cable provided real-time telemetry from a casing collar locator (CCL) downhole tool to a digital data interrogator on the surface to gain more accuracy in the horizontal section. Once precisely positioned, the CT was pressurized to activate the hydraulic setting tools for plug set and activating the firing head for perforation guns fired at the exact target depth. Using CT deployment, the operator also avoided the gun moving upward and becoming stuck in the well, which is a risk with a wireline and tractor application. The fiber-optics application also enhanced wellbore cleanout efficiency after fracturing with the advantage of real-time downhole circulating pressure.

The application goals were achieved as planned for this project, proving that CT can be used in this horizontal well section in conjunction with fiber optics. The fiber-optic real-time digital data from the downhole tool provided more accurate depth measurements for placing plug set and perforations, as well as monitoring bottomhole pressure to control smooth sand cleanout in the wellbore. This application also helped minimize the risk of operational failures due to the perforation gun moving upward after firing and the risk of the downhole tool becoming stuck (because CT can have larger pulling capacity than electric line operations). This new application also proved to be cost effective because CT fiber-optics applications can perform both perforation and sand cleanout operations, eliminating the requirement for electric line and tractor on location, saving both time and costs.

The advantages and benefits of using the CT fiber-optic digital application for placing bridge plug, perforations, and sand cleanout in horizontal well completions have shown significant improvement in terms of operational efficiency, cost savings delivered to meet the well operator's budget, and safety supporting multistage fracturing zones.

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