Mechanical Cleaning of Calcite Scaling with Rotating Control Head Preventer in a Geothermal Well

Abstract

This paper presents the mechanical methods used for calcite scale cleaning of wells in the Kizildere geothermal field in Western Turkey. A geothermal power plant with a capacity of 20.4 MWe has been operating in the field since 1984. During production well diameter reduces because of calcite scaling which has been a continuous problem since the beginning of energy production from the field. The calcite scaling decreases power generation from 15 MWe to 10-12 MWe, increase capital cost, pumping costs and cleaning and maintenance costs. Scaling in the wells has been mechanically reamed periodically since 1984 to increases the production from the wells. Since mechanical cleaning with mud or water circulation causes reservoir contamination, KD 7 well was reamed while the well was flowing using Rotating Control Head Preventer (RCHP) for the first time in 1990. This method has been used successfully since 1991 at all wells. In this study the results of the mechanical cleaning with mud or water, and mechanical cleaning with Rotating Control Head Preventer methods were evaluated.