Workover Challenges Using Hydraulic Workover Unit in Dieng Geothermal Field

Abstract

Dieng Geothermal Field is situated in Central Java at around 2,000 masl and the Dieng Unit 1 Power Plant has been operating since 2002. The existing power plant configuration in Dieng Geothermal Field is 1 x 55 MW, but currently producing less due to the several problems in its wells. The most common problem in Dieng Geothermal Field is the severe scaling in the production well that decreases the wellbore diameter, thus reducing the geothermal fluid produced from the reservoir. A workover campaign has been designed to overcome the scaling problem in the most effective and economic way. There are several challenges in performing workover in Dieng Geothermal Field, such as the presence of the existing production facilities, the high hardness of the mineral scale, and casing damage through the course of the production. A proper workover method with fit-for-purpose rig is significant to ensure a successful workover operation. This paper examines the challenges in performing workover in the wells in the Dieng Geothermal Field, both from technical and non-technical aspects. The decision-making process of selecting Hydraulic Workover Unit as the preferable workover equipment in some wells in Dieng Geothermal Field is also discussed, including the advantages and disadvantages of using Hydraulic Workover Unit to perform the workover.