Studies of the Reinjection Tests in Basement Geothermal Reservoir, Tianjin, China

Abstract

By the end of 2003, about 235 production wells(including 14 reinjection wells) have been drilled in Tianjin. The annual production rate was 24Mm3 in 2003 and the reinjection rate was about 1.7Mm3. The depth to the water level ranged from 22 to 70m and the draw-down rate was 6-9 m/year. The effect of reinjection in the WR45 doublet was analyzed. However, up to now, no temperature changes have been observed in surrounding geothermal production wells. The main side effect anticipated from reinjection is a cooling of the reservoir. Tracer tests are very important for understanding the mode of transport and flow-channel/fracture-space characteristics in doublet production/reinjection systems, and for estimation of the possible cooling that can result from injection.