| Abstract |
The Bottom hole assembly (BHA) is designed based on various factors: hole geometry, mud weight, loads and forces, safety factor, components (drill collar, heavy weight drill pipe/HWDP, jars, etc.), inclination and direction, formation rocks (hardness and lithology). The study presented here discusses the lesson learned of BHA design and performance of drilling geothermal well HCE-28A in Field Dieng, Indonesia. The well is characterized with high temperature up to 316oC, pressure up to 15.7 MPa, presence of corrosive substances (CO2, H2S, and chloride) and environment (pH 4-5), and hard formation rocks. Major problems, such as high dogleg severity (DLS), tight hole, stuck pipe, and loss circulation occurred during drilling operation of this well. Such problems affected the BHA performance. This study was focused on BHA performance at depth 1,500-2,100 m MD in 12 ¼†hole section. Five BHA in this hole section were selected for the analysis. The result of this study improves the design of BHA and the quality of the borehole according to the requirement from the reservoir and production point of view. The result and the lesson learned are used in designing BHA for the next well drilling campaign in this Field. |