Evaluation of Testing and Reservoir Parameters in Geothermal Wells at Raft River and Boise, Idaho

Abstract

Evaluating the Raft River and Boise, Idaho, resources by pump injection tests requires information on the geology, geochemistry, surficial and borehole geophysics, and well construction and development methods. Nonideal test conditions and a complex hydrogeologic system prevent the use of idealized mathematical models for data evaluation in a one phase fluid system. An empirical approach is successfully used since it was observed that all valid pump and injection well pressure data for constant discharge tests plotted as linear trends on semilogarithmic plots of borehole pressure versus time since pumping or injection began. Quantification of the pressure response prior to 600 minutes is not always possible. Short duration (<24 hours) injection or pump tests are conducted within the drilling rig equipment, and long duration (21 day) injection and pump tests are then conducted with permanent pumping facilities. Replicate instrumentation for pressure, temperature, and flow rates are necessary to ensure quality data. Water quality and monitor well data are also collected.