An innovative sensor system has been deployed on the Maria field offshore Norway, providing the field’s operator Wintershall with improved well integrity monitoring and offshore safety.
The latest deployment of the system – a wireless solution that delivers crucial integrity data and measures online and real-time pressure and temperature information from behind the casing in subsea production wells – follows the successful deployment of several dozen systems in other fields over the past four years, all providing crucial data to offshore operators on the status of their well barriers and casing.
The pressure and temperature monitoring system allows Wintershall to verify that the predicted pressure build-up falls within the design criteria, and an alarm trigger point is implemented in case pressures that are potentially outside the system design are reached.
The Roxar Downhole Sensor System also comes with new advances that enable operators to access online displays and trending of previously unreachable temperature and pressure subsurface data behind the well casing and achieve online integrity verification without any impact on production. The system, that has been tested at 225°C and can withstand pressures of up to 1,380 bar, has already generated considerable direct savings for operators, due to reduced testing requirements and more time to focus on production.
“After continued sales and further advances to the system, the Roxar Wireless Downhole Sensor Solution has reached full maturity,” says Sturle Haaland at the system’s creator, Emerson Automation Solutions. “Operators now have the information they need to make informed decisions on well integrity, adhere to regulatory requirements, ensure offshore safety, and enable their wells to produce at optimal levels.”
The added knowledge on pressure and temperature dynamics delivered by the system’s highly accurate quartz gauges in previously unreachable parts of the completion has also led to a better understanding and confidence in operators’ well integrity strategies. The system ensures that wells meet integrity monitoring standards, such as API RP90 and NORSOK D-010. It also has a Technology Readiness Level of TRL7 as per API RP 17N “Recommended Practices for Subsea Production System Reliability, Technical Risk and Integrity Management.”
The Roxar Downhole Sensor System is powered using an inductive coupling system developed in-house with no need for batteries, making it ideal for harsh environments and the high pressure/high temperature surroundings often found offshore. The sensor is installed externally to the steel casing and may be cemented in place in the well. Continuous power and data to and from the sensor is then transmitted wirelessly through the steel casing to ensure maximum well integrity for the life of the well and enable any anomalies to be detected early and in real-time (something that would not be the case with periodic testing). The sensor system may be placed at any depth in the well completion system and has the ability to penetrate more than one set of steel casings. It is an integral part of the Roxar Intelligent Downhole Network currently installed in thousands of wells worldwide. The addition of the system to the network requires no additional hardware to the subsea control system.