Completion Design for Sandface Monitoring of Subsea Wells

Abstract

Summary The expense of subsea well intervention often leads to insufficient reservoir information for accurately understanding reservoir connectivity, drainage, and flow assurance. For those wells requiring sand control, an additional constraint is that sandface sensors must be deployed on a separate completion run. The objective of a recent engineering development program was to create a new deployment system that addressed these constraints directly. Instead of individual gauges on mandrels, digital sensors were miniaturized and distributed along a single spoolable bridle. In addition, a novel inductive coupling mechanism was developed to pass power and data from the upper to the lower completion. In a recent subsea deployment in southeast Asia, such a coupler was attached to the top of a sensor bridle and both were deployed as part of an openhole gravel-pack completion. Standard packers and gravel-pack service tools were used. The system became activated when a mating inductive coupler was landed as part of the upper completion. Surface indication of landing was provided by incorporating mechanical feedback into the lower assembly. With the coupler components in position, the tubing hanger was landed into the horizontal tree. Upon activation of the electrical penetrator, high-resolution temperature data were then immediately available across the length of the sandface, which was an industry first for a subsea producing well. No additional penetrations were required in the tree. Development of this system required coordination from the operator because of the multiple vendors involved in the project. They supervised multiple qualification and system-integration tests performed over the 2-year development period to ensure ultimate success in the subsea deployment. Field results showed that the mating inductive couplers provided high-efficiency of power transmission so that industry-standard power settings were sufficient to power a bridle with one sensor per joint of screen. The sandface data were available onshore during the cleanup phase, allowing the operator to monitor the cleanup in real time. Once the wells are brought on line, the sandface data will further enhance the interpretation of flow allocation and reservoir drainage.