Questions 1 a) A geothermal well produces water from a formation 8 000 ft below the surface. Formation temperature is 520 F. Estimate the flowing surface temperature at 1, 10 and 30 days producing time at a rate of 8.4 x106 lb/day using the data below. Heat capacity of water = 1.0 BTU/16-F Heat conductivity of the formation = 35 BTU/day-ft-OF Thermal diffusivity of the formation = 1.04 f/day Radius =r=0.35 ft Earth temperature at surface = 70 F = B) |Following data are given for a geothermal reservoir: Temperature = 200 C. Porosity = 0.10, Water saturation = Sw = 1.0 Rock density = 2000 kg/m?, Rock specific heat = 1000 J/(kg-C) Mass fraction of CO2 in water = XCO2 = 0.015 Molality = M=0.07 Mol/kg H20 (NaCl molality) (a) Find pco2 and CO2; compare it with Cw @ 1000 psi = 6895 kPa. (b) Assume that CO2 does not exist in the reservoir water and the reservoir is at the two-phase saturated conditions; determine two-phase compressibility (Ct) and compare it with Cs, Cw, CC02. c) Given the earth properties below, assuming a steam producing formation is encountered at a depth of 6 000 ft and a temperature of 520 F. compute the enthalpy of the steam at the wellhead for a production rate of 80 000 lb/hr and a time of 14 days production. Assume the steam is saturated at initial formation conditions. Present answer in units of BTU/lb. Heat conductivity of the formation = 33.6 BTU/day-ft-OF Thermal diffusivity of the formation = 0.96 ft/day Radius =r=0.33 ft Earth temperature at surface = 70 F d) A lake on the hill of a mountain releases 80 million cubic meters of water. This water falls through the 200 meter height difference down to the final outflow at the power plant location. (a) Find the gross energy release (potential energy in MJ (mega Joule)). (b) Find the gross power in MW.. (c) Find the energy generated in a year (in kW-hr)