The Field Kelvin Probe for contactless detection of corrosion potentials: capabilities and implementation

摘要

It has been long recognised that corrosion causes major operative costs to the offshore oil and gas industry. Traditional detection, utilising either acoustic, electromagnetic or radiation sensing elements, typically report ongoing corrosion and therefore are regarded as reactive technologies. The Field Kelvin Probe (FKP) is a promising new technology thought to promote truly predictive corrosion detection in the harsh offshore environments. At the core of the FKP, a capacitive sensor enables non-contact detection of corrosion potentials of either bare or coated metallic surfaces. This work presents the operating principle, building blocks and in addition, it touches on the main mechanic and electronic design solutions, which are necessary for the successful FKP deployment on offshore oil / gas rigs. In addition, this work features the unique, build-in self-calibration mechanism, which could eliminate the need for periodic statutory calibrations thus increasing instrument availability and reducing operation costs. We are discussing a set of long-term laboratory measurements performed with an FKP mounted on a XZ-scanner on paint-coated samples of steel grades ranging from low carbon to highly alloyed stainless steel. By critically viewing such test results, we aim at selecting the best possible FKP configuration suitable for the offshore environment.