Calcite Inhibition Systems Tubing Recovery

Abstract

Chemical Inhibition Systems (CIS) are widely used in geothermal wells to deliver antiscalant chemicals that mitigate mineral scaling. Over time, CIS tubing can become stuck due to scale buildup, caused by inappropriate chemical selection, changes in fluid chemistry, and lack of routine maintenance. This paper presents field-proven results using the Solenis chemical cleaning method to dissolve scale and recover immobilized CIS tubing in high-temperature geothermal wells.
The method has been successfully deployed in geothermal fields in New Zealand and the Philippines, with each case involving different scale types—primarily silica, calcite, and mixed mineral compositions. We detail the assessment process, tailored chemical program design, and safe retrieval procedures that avoided more costly well intervention methods involving a rig or coiled tubing unit. These interventions restored injection capability, improved well performance, and extended system life. The paper discusses practical recommendations for preventing stuck tubing and optimizing CIS reliability across a variety of geothermal environments.