ARCHITECTURAL PERMEABILITY MODEL IN HULULAIS GEOTHERMAL FIELD BASED ON SURFACE AND SUBSURFACE DATA

• Main Author: Trianggo Nurseto, Sapto
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/61676
• Institution: Institut Teknologi Bandung

This research is about modeling the permeability architecture based on the interpretation and integration of surface and subsurface data including geological, geophysical, geochemical and well measurement data. The background of this research, as it is known Hululais is in a volcanic complex and an active geological structure zone, nonetheless it is difficult to get a permeability zone, especially for the reinjection zone, even though Hululais still needs make-up wells for the next thirty years to keep producing of 2x55 MW. The purpose of this study is to create a permeability model with a high level of confidence and able to provide an overview of the geometry and control of permeability, is it controlled by primary and/or secondary permeability. The architecture of the permeability model is carried out in four stages, the first stage is to study and interpret geological, geophysical and geochemical data to confirm the existence of lithology and geological structures. The second stage is to analyze feedzones based on well testing data, from this stage a confirmed permeability zone distribution will be obtained. The third stage is to integrate data between lithology and geological structures with permeability zone data, from the integration of these data will be obtained lithological geometries and productive geological structures that are validated with data as permeability distribution maps. The fourth stage is to describe it into a three-dimensional model. The results of this study indicate that the lithology who controls primary permeability is controlled by volcaniclastic rocks and andesite lava which is part of the Lower Suban Agung Volcanic and Hululais Volcanic formation, meanwhile the geological structures of the Suban Agung Hilir Fault with BL-Tg direction, Cemeh Fault with UBL-STg direction and Gregok Fault which is U-S direction is a productive geological structure that plays a role of secondary permeability control. The recommendation from this research, for the next make-up wells targeted should towards to Suban Agung Hilir Fault, Cemeh Fault and Gregok Fault, the drilling also must through the Lower Suban Agung Volcanic and Hululais Volcanic formation.