OVERPRESSURE DI LAPANGAN “X”, CEKUNGAN KUTAI, KALIMANTAN TIMUR: KARAKTERISTIK, PENYEBAB, DAN HUBUNGANNYA DENGAN AKUMULASI HIDROKARBON

• Main Author: Nursasono, Danny
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/34386
• Institution: Institut Teknologi Bandung

Semberah Field is one of oil and gas fields that has been producing oil and gas in Kutai Basin. Historically this field has overpressure zone. To date production zone in this field is only in normal hydrostatic zone. Hence, drilling activity in this field has never reached overpressure zone. Another research in the Gulf of Mexico (GOM) shows that there is correlation between overpressure zone (transition zone) and hydrocarbon accumulation. This circumtance serves as background of this research. The first step in this research is analyzing overpressure characteristic (overpressure zone, mechanism, and its transition zone) in this field by using drilling events data (connection gas, kick, loss, background gas, etc), pore pressure measurements, and wireline logs data. Additional data such as vitrinite reflectance (Ro) and temperature are used to analyze the mechanism of overpressure. Result of the analysis shows that overpressure zone (transition zone) generally starts at Kampung Baru Formation (marker i and j). The overpressure mechanism in this field is unloading caused by hydrocarbon maturation and clay diagenesis (smectite to illite transformation). The final step of this research is collaborating overpressure characteristic and hydrocarbon production/accumulation data. The collaboration shows that reservoir in overpresure zone (transition zone) has a better/higher value of netpay than in normal hydrostatic zone. Moreover, hydrocarbon production/accumulation data show that the accumulation in overpressure zone (transition zone) contributes to about ± 65% of total gas/condensate production in this field. This fact shows that overpressure zone (transition zone) could trap hydrocarbon better than normal hydrostatic zone in Semberah Field