Emerson Process Management has introduced the Roxar Downhole Wireless PT sensing system - Annulus B, which is capable of measuring pressure from places like behind the well casing of subsea production wells.
The product was launched at the Annulus B at OTC 2011. The new sensor is capable of providing pressure and temperature data in real-time, which would be of immense help for well operators.
Roxar Downhole Wireless PT Sensor
A well usually contains two annuli. The A annulus is the space between the smallest casing string and the production tubing and the B annulus is the space between varied casing strings. The integrity of the casing depends on the cement sealing, which protects it against high pressures deep inside the well. In cases where the casing is exposed due to poor quality or deterioration of the cement seal, the oil or gases escape out from the casing, which may lead to gas blow out. The Annulus B, which has online pressure monitoring capability, can be used to ensure the integrity of the casing. The sensing system is also capable of nullifying the effect of over dimensioned casings and contributes to trouble shooting operations in the well.
The Integrated Downhole Network carries the signals from the well to the monitoring system through a downhole network controller card, which is located at subsea level. This is connected to a set of 32 sensors that are present throughout the completion strings via a ¼” cable. A wireless PT transponder, antennae, a wireless reader and a transponder and reader carrier are other components in the system. The system can sustain for a period of 20 years subjected to pressures up to 10,000 psi and temperatures up to 302°F.
Source: http://www2.emersonprocess.com/en-US/Pages/Home.aspx