DEVELOPMENT OF HIGH EROSIVITY CAVITATING AND ACOUSTICALLY ENHANCED WATER JETS FOR WELL SCALE REMOVAL

摘要

The walls of geothermal wells often experience rapid build up of scale deposits due to the high dissolved solids content of geothermal fluids. As the liquid is brought up from deep wells, its pressure drops, and the water flashes to steam resulting in precipitation of dissolved minerals. Existing means of addressing this problem such as chemical inhibitors, removal with conventional water jet blasting, drilling with a workover bit, or acids are costly and not always effective, particularly with the harder scales such as silica. Our ongoing effort seeks to develop cavitating and acoustically enhanced water jets for geothermal well scale removal. These technologies have been proven to enhance the erosive power of liquid jets by several fold in various cutting, cleaning, and drilling applications particularly for hard materials and thus promise to substantially enhance the performance of down-hole cleaning tools, particularly for the removal of hard scale. Initial results from laboratory experiments on cutting of both actual and simulated are presented. Experiments are reported under simulated down hole conditions over a range of ambient pressures and standoffs. Scale removal and cleaning rates are compared with those obtained from conventional water jet nozzles, and the improvements presented.