Perpustakaan Digital ITB

Drilling cost of well take up to 50% of the total project cost for a geothermal power plant. The longer it takes to drill a well, the more expensive the well becomes. Therefore, it is crucial to optimize the time spent in drilling to optimize the cost of a well. To achieve it, identification and analysis of the non-productive time (NPT) incurred while drilling a well is necessary. This study discusses an Indonesian vapor-dominated geothermal exploration well that failed to reach the final trajectory with the last status remaining idle. A review of drilling operations was carried out in this study by comparing and visualizing well plans with actual operations. However, there was a more non-productive time (NPT) found than productive time (PT). The results of the identification and analysis state that almost all causes of NPT are borehole problems. Several recommendations from related literature for pre-drilling and post-drilling operation are also proposed at the end of this paper. These recommendations can be applied to improve future wells drilling operation and hence saving on costs.