Fabrication and design of CNTs inkjet-printed based micro FET sensor for sodium chloride scale detection in oil field

Formation of mineral scale on pipes, well bores and production tubing is a major issue for oil and gas industries that results in loss of production and reliability issues. Early warning of scale conditions is of great importance, since wells can scale up within 24 h or less. Although multiple studies have been conducted on scale monitoring, most of techniques imply offline sample testing, which are time consuming and not reliable most of the time. Carbon nanomaterials (CNM) have demonstrated to be a promising sensing material because of their unique electrical and mechanical properties. In this paper, we present carbon nanotubes (CNTs) based field effect transistor (FET) sensor suitable for mineral scale detection. CNTs films are deposited and integrated into an FET like device using inkjet printing technique optimized for this particular application. The sensor device shows a significant response to chloride scale, with sensitivity of the CNTs based sensor towards 3% NaCl solution equals 8.6. Important characteristics, such as sensor recovery and repeatability have been investigated and demonstrated.