This study presents an investigation of the concept of harvesting geothermal energy thatremains in heavy oil reservoirs after abandonment when steamflooding is no longereconomics. Substantial heat that has accumulated within reservoir rock and its vicinitycan be extracted by circulating water relatively colder than reservoir temperature. Weuse compositional reservoir simulation coupled with a semianalytical equation of thewellbore heat loss approximation to estimate surface heat recovery. Additionally,sensitivity analyses provide understanding of the effect of various parameters on heatrecovery in the artificial geothermal resources. Using the current state-of-art technology,the cumulative electrical power generated from heat recovered is about 246 MWhraccounting for 90percent downtime.Characteristics of heat storage within the reservoir rock were identified. The factors withthe largest impact on the energy recovery during the water injection phase are theduration of the steamflood (which dictates the amount of heat accumulated in thereservoir) and the original reservoir energy in place. Outlet reservoir-fluid temperaturesare used to approximate heat loss along the wellbore and estimate surface fluidtemperature using the semianalytical approaches. For the injection well with insulation,results indicate that differences in fluid temperature between surface and bottomhole arenegligible. However, for the conventional production well, heat loss is estimated around13 percent resulting in the average surface temperature of 72 degrees C.Producing heat can be used in two applications: direct uses and electricity generation.For the electricity generation application that is used in the economic consideration, the net electrical power generated by this arrival fluid temperature is approximately 3 kWper one producing pattern using Ener-G-Rotors.
展开▼
