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11. OPERATION AND RESULTS The low-temperature heating test at EF3 has been operated under thermostatic control. The control and data acquisition system for the experiment is illustrated in Figure 16. Every temperature measured in the experiment is used in the thermostat, whether it's from a thermocouple or the fiber optic temperature system. The control functions are implemented entirely within the mine and do not rely on the data recording functions in the field office. To accomplish this, data acquisition hardware in the mine interfaces directly to the control unit on the power skid Data Acquisition Software Voltage, Thermocouple Fiber optic Field Office USB current, power temperatures temperatures (recording) to fiber - (1 min freq) (12 min freq) (12 min freq) --------------------------------- Mine Control Logic (acquisition USB If on: any temperature >1350F - turn off TO 0B4 & control) to fiber If off: TC temperatures below 110°F after TC and 0B9 thermostatic shutoff - turn back on Over Alarms . uunLULUIW, i ii Signals Fiber optic Thermocouples and temperatures electrical data Figure 16. The EF3 low-temperature heating experiment has been operated under thermostatic control. Figure 17 is a 3-D display showing temperatures at EF3 on September 21, eight weeks into the heating experiment. Elevated temperatures are evident in the area between the two electrodes, and several of the fiber optic holes parallel to the fracture have elevated temperatures over an extended length. This indicates we're achieving moderately uniform heating over the body of the fracture. While 3D displays provide a good qualitative picture of the heating, 2D contour plots on the driving the Electrofrac. The power skid includes a large variable transformer, connected to a 2X step- up transformer. The skid can deliver up to 960 volts to the fracture. A small computer network in the field office records data from the mine via a fiber optic communications link. Heating in this low-temperature experiment was initiated on July 27, 2009 and continued until October 30, 2009. During that period the average power delivered to the fracture was 7.9 kW. fracture surface are easier to interpret quantitatively. Figure 18 shows normalized voltages and temperature rises measured on the fracture surface. These contour plots are somewhat approximate because the fracture is not actually planar, but instead follows a somewhat curved surface. 29th oil Shale Symposium Page 11 of 13 October 19-23, 2009