ALTERATION AND MAJOR ELEMENT MOBILIZATION STUDY OF X AND Y WELL AT GEOTHERMAL POTENCY AREA TOMPASO, NORTH SULAWESI

• Main Author: MALIANI (NIM : 22106339), ANI
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/19891
• Institution: Institut Teknologi Bandung

Research study is located at Tompaso Geothermal Field, North Sulawesi. The purpose of study is to find out the characteristic of alteration minerals and to describe its concept of geothermal system. The X well source rocks are predominated by volcanic breccias mainly consists of local basalt, tuff, and polimic breccias. The magmatic activity is characterized by tholeitic to <br /> <br /> calc-alkaline. Major element mobilization shows the existence of Na enrichment. The alteration type of X well develops from argillic to propillitic. The argillic type marked by the occurrence of smectite, kaolinite, mixed layered of smectite-illite, mixed layered chlorite-smectite and illite while the propilitic type characterized by clorite, calcite, and epidote present. Locally, overprint propilitic by argillic was present. The formed minerals temperature increases while X well is deeper. The temperature is 140oC at 132 - 450 <br /> <br /> MKU, and increase to 190oC at 500 MKU, rises to 230oC 1745 MKU. Boiling indication at X well marked by the bladed calcite present at 1152 MKU. Thus, the alteration <br /> <br /> minerals are formed at neutral fluid environment even some minerals are formed in acid environment at shallow depth. The concept model of geothermal system in X well is supported by two alteration zones; firstly, the distribution of argillic alteration type as cap rock which identified at 132-1002 MKU and ± 713.62 m thick. And secondly, the reservoir zone identified by distribution of propylitic alteration zone as reservoir zone which is performed at 1002-1745 MKU and ± 425 m thick.