Evaluation of Steam Production Decline Trends in the Kamojang Geothermal Field

Abstract

The Kamojang geothermal field is currently producing about 1100 tons/hour of steam supplying three turbines with 140 Mwe of installed capacity. The turbines are supplied by steam from 31 wells which is delivered through 4 main pipelines.

The decline of steam flow rate of production wells in the Kamojang fields has been analyzed using type-curve exponential and harmonic matching decline models. The decline rate observed shows a larger decline rate in some low producing wells within the low permeability regions. Most of the low producing wells are operated at low WHP, which caused an exponential decline trend due to silica deposition.

There are 3 injection wells operating in the center part of field. Some production wells which are near to the injection wells tend to have a smaller decline rate. Superheating occurs in some of the wells in the South and West side of the field, based in down hole temperature measurement. The affect of injection wells in operation are also analyzed and discussed.