New downhole caliper logging tool

Expro International Group PLC (Expro Group) says it is introducing new, accurate downhole calipers, DigiCal, with which mechanically recorded downhole data is converted to e-data at surface using the latest digital scanning technology. DigiCal is said to combine the reliable HP/HT capabilities of Kinley's calipers with the latest in digital interpretation technology for corrosion monitoring suitable to all locations but especially those in extreme conditions and remote sites.

The Kinley caliper can be run to a maximum temperature of 600°F and a maximum pressure of 20,000 psi with no limit of H₂S or CO₂ concentrations. Furthermore the caliper does not suffer from any pressure- or temperature-related drift on sensors over recorded depths of up to 30,000 ft.

The caliper's mechanical nature enables it to continuously record the position of each feeler simultaneously, rather than taking sequential spot readings of the position of each feeler in turn, as is the case with its electronic counterparts. The combination of both the tool's temperature stability, and continuous independent recording of each feeler results in greater accuracy and resolution.

The Expro Group says the DigiCal system enables mechanically recorded data in the tool to be converted into a more convenient electronic format as soon as the tool comes to surface. The resulting e-data can then be processed using unique interpretation and visualization software to produce a corrosion log at the wellsite. The e-data can also be transmitted to the Expro Group's Corrosion Analysis Center for a full analysis by a team of specialists within hours.

The Expro Group acquired the largest fleet of multi-finger calipers in the world through its acquisition of the Kinley Corporation in March 2000. Kinley's range of calipers allow tubing and casing sizes from 1.9 inches (49mm) up to 13 5/8 inches (344mm) to be logged.