| Abstract |
This study investigates the probability of solid particles reaching the surface facilities for a closed-loop geothermal system due to the risk of particle accumulation in the surface equipment. A major concern for facility operation is solids reaching critical surface equipment such as the heat exchangers. This could potentially result in plugging, fouling, and corrosion of the surface equipment. The effects of particle accumulation include reduced fluid flow, an increase in pressure drop, reduced heat transfer efficiency, and structural damage to equipment. Left-over drilling debris has the potential to enter and circulate through the geothermal system’s subsurface open hole laterals. The concentration of solids expected during loop circulation start-up and normal operation thereafter is dependent on the initial handover state of the loop from drilling to operations. Once the geothermal working fluid is circulating, flow rate and temperature impact the potential for solids to travel approximately 5 km to surface. Prior to start-up and circulation of the geothermal loop, several calculation methods are employed to estimate the particle distribution at surface. This preliminary analysis is then compared to actual performance data obtained during circulation of the loop working fluid. During drilling activities involving loop circulation, sampling of the geothermal working fluid is performed to provide actual results for particle size distribution. A comparative assessment of the predictive modelling against collected particle data is conducted to inform and refine the accuracy of initial modelling used to predict particles reaching the surface facilities. |