Reservoir Evaluation for the Wuqing Geothermal Field, Tianjin, China

Abstract

The Wuqing geothermal field is a typical low-temperature system, which is located in the middle-lower reaches of the Haihe River System on the North China plain. It is an extensive horizontal sandstone zone with temperature of 76- 86?C. The production rate of the whole field has reached to 1.18Mm3 in 1997/1998. A distributed parameter model for the Wuqing geothermal field is set up, using the VARFLOW program. The characteristics of the reservoir are calibrated by analyzing the well test data and matching the measured and calculated water level from six production wells over the past five years. Based on this, predictions of the reservoir response to the planned production and reinjection rates were made up to the year 2003. The flow model indicates that the reservoir will reach near to steady-state condition early in the predicted period. The maximum production rate without injection will cause draw-down of 106 m. The draw-down water level can be reduced 15 m if three doublets are employed for injection/production. The thermal breakthrough time and pressure support of reinjection is also discussed.