XACT service monitored fluid levels, minimized reservoir damage
To minimize fluid losses and associated formation damage in an offshore deepwater well, a major operator needed to maintain optimum overbalance at the formation. The traditional method was to drop and control the fluid levels in the riser annulus.
Conventional measurement techniques, such as echo meters, had proved problematic in accurately measuring riser fluid level, and in providing the real-time updates required to manage inflow proactively. Fast updates are particularly needed during perforation and acidization operations, when fluid levels need continual monitoring. Additionally, any in-well tools had to be fullbore to allow the passage of wireline tools needed to operate a formation isolation valve.
Working with Baker Hughes, a GE company (BHGE), the operator’s engineers decided to deploy the XACT™ downhole acoustic telemetry service—a technology they have been helping to develop—to more reliably and safely control fluid levels to minimize reservoir damage. Integrated measurement and acoustic telemetry nodes were positioned in the riser at 3,500 ft and 7,500 ft (1066 and 2286 m) below the rotary table. Bore and annulus pressure data was acquired and displayed at surface to determine the top of the mud column relative to the rig floor, and hence the volume of mud above the tools. Data was transmitted every 25 seconds throughout the operation, enabling the operator’s engineers to safely monitor the well through all operations, including tripping in and out of the well. The XACT service was deployed both during the tubing conveyed perforating (TCP) gun run and the upper completion installation.
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