PRODUCTION IMPROVEMENT THROUGH SCALE REMOVAL BY JETWASH KAMOJANG GEOTHERMAL FIELD

Abstract

The Kamojang geothermal field, Indonesia, is a vapor-dominated system with a total installed capacity of 235 MWe. Kamojang currently has five power plants (i.e., Units I-V). Unit I generates 35 MWe, Units II-III generate 55 MWe each, Unit IV generates 60 MWe, and unit V generates 35 MWe. During more than 30 years of generation the production wells have decreased in production. This directly affects the steam supply to the power plants. The most important program to resolve steam availability is drilling a makeup well. Limited access and unsuccessful drilling of makeup wells during 10 years have become a problem for maintaining long-term production.
Generally, in the Kamojang field the decline of production is affected by hole problems or reservoir damage. Seven wells indicated a hole problem due to scaling such as KMJ-A, KMJ-B, KMJ-C, KMJ-D, KMJ-E, KMJ-F, KMJ-G, KMJ-H, and KMJ-I. In this case, hole cleaning aims to dissolve scaling that causes decline of production. Hole cleaning uses jetwashes (water blasting) with 45 and 90 degrees nozzles to clean the scale of the production casing and liner.
As a result, a total of seven wells have increased production after hole cleaning, gaining approximately 8 MWe. Additionally, steam through jetwash can reduce cost, time, and drilling makeup wells.