The Geothermal Industry’s largest remedial budgetary cost involves the removal of scale from its existing completions. From it’s inception forty years ago, the geothermal industry has tried many different systems and applications for the removal of very hard scale from their injection and production wells. Today the most widely used and accepted method for hard scale removal has been the use of a workover rig utilizing a bit and scraper. This method, although partially effective, does not fully address the impediment of scale in the well conduit – a bit and scraper simply cannot remove what it cannot reach. In addition, with the advent of high alloy materials to combat the corrosion effects of these scales, along with pressure depleted formations, this method is proving to be inadequate as it can cause severe damage to the expensive wellbore tubulars. This paper reviews and discusses several case histories of a newly developed technique for removing these very hard geothermal scales.

Keywords:
society of petroleum engineers, liner, hard scale, upstream oil & gas, nitrogen, geothermal well, bridge, completion installation and operations, injectivity, fluid system
Subjects:
Pressure Management, Drilling Fluids and Materials, Well & Reservoir Surveillance and Monitoring, Formation Evaluation & Management, Non-Traditional Resources, Professionalism, Training, and Education, Information Management and Systems, Geothermal resources, Completion Installation and Operations, Well Intervention
Copyright 2000, Society of Petroleum Engineers
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