2005 年 27 巻 4 号 p. 321-336
Well H-30 started periodic decrease and recovery of its productivity since March 2002. The well had, then, lost the productivity such that it can not maintain wellhead pressure high enough to be connected to the two-phase flow pipeline network that transports the fluid to the main separator by the power station. A schematic reservoir model in the vicinity of the well was developed to explain these fluctuations using the results of well characteristics measurements, geochemical monitoring of produced fluids, production logging and tracer tests. The production history of well H-30 was divided into three periods on the basis of its productivity performance. The fluctuation in productivity was attributed to the excessive inflow of the separated water reinjected at wells near well H-30. Reducing the reinjection rate at nearby wells and/or the rate of mass production at well H-30 were recommended for stable production of well H-30.