Well Inlet Pressure and Steam Quality of Hatchobaru Production Wells

Abstract

Steam water two phase flow analysis in a wellbore were carried out to estimate pressure and steam quality of geothermal fluid at well inlet, using the field data of Hatchobaru production wells observed in the past two year. The calculated results suggest that two phase condition is dominant at the well inlet which means the geothermal fluid starts flashing in the reservoir and enter the wellbore as two phase mixture. Well inlet steam quality are not uniform but differs widely in the range from 0.1 to 0.7. Two wells intersecting through fracture at shallow zone of the reservoir show the stem of high quality more that 0.5 and increase with time. Larger increase in well inlet pressure explains that flash point moves into the wellbore from the reservoir due to the decrease in saturation pressure which may account for the effect of mixing of reinjection water.