High-temperature MEMS gyroscope survives down-hole oil/gas deployment

September 04, 2014 // By Graham Prophet
Specified to 175C operation, the ±2,000°/sec ADXRS645 MEMS gyroscope replaces magnetometers in down-hole drilling applications as a reliable method of rotational measurement.

Analog Devices says it has the first and only MEMS gyroscope specified to withstand temperatures of up to 175C commonly encountered by oil and gas drilling equipment. The ADXRS645 provides vibration immunity and a minimum rotational measurement range of ±2,000°/sec, which are critical performance criteria for drilling tools operating in harsh, high-temperature environments. The ability to accurately sense angular rotation prevents drill string damage by detecting the difference between drill head rotation and the motor turning the drill. This allows rig operators in the oil and gas industries to extend the life of their equipment and reduce costly downtime by ensuring that the drill string is operating properly.

The ADXRS645 features low, 5-V single-supply operation and is the only MEMS gyroscope to operate at up to 175C for a minimum of 1,000 hours of operation. Its unique ceramic vertical-mount package allows the device to be robustly mounted to the PCB and eliminates the need for an orthogonally-mounted daughtercard.

ADI has a portfolio of precision high-temperature components designed for drilling applications, including the ADXL206 ±5g precision MEMS accelerometer, the AD8229 ultra-low-noise instrumentation amplifier, the ADR225 2.5-V band gap voltage reference and the AD8634 dual amplifier with rail-to-rail outputs, all of which are specified to operate at 175C, and higher.

The down-hole drilling industry is adopting a multitude of sensors to better understand the motion of the drill string below the surface to optimise operations, prevent drill damage, and increase productivity. Other approaches to rotational measurement, such as the use of magnetometers, are susceptible to drill vibration, are unable to precisely capture fast-changing rotational speeds and their readings can be impacted by ferrous material or metal casings used in the well.

In a custom, 8 x 9 x 3-mm ceramic, side-braze, through-hole package, the device costs $975 (1000).

Analog Devices; http://www.analog.com/ADXRS645?utm_source=ADXRS645_PR&utm_medium=PR