DISTRIBUTION ANALYSIS AND RESERVOAR MODELING OF ZONE J-20, SANTUL FORMATION, TARAKAN BASIN, NORTH KALIMANTAN

• Main Author: IRWANZAH BUDIARTO, ZEPPY
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/19767
• Institution: Institut Teknologi Bandung

Bunyu Field is a mature field that has experienced natural increase and decrease in production. Despite of it, the production in this field was reincreasing due to the impact of development-drilling in the Northern area. This success also noted with the new discovery wells that having the “virgin” character, large Qoi value (average 2000 bpd) and its inceasing the total reserverse of oil and gas in Bunyu field. The reservoirs is part of Santul that had been proven producing hydrocarbon from its channel and mouth bar facies. Field development strategy is very important to develop complex area such as delta environment. Subsequently, by the increasing of oil production and finding other potential layers, we need to construct a good understanding of depositional environment, reservoir geometry, compartementalization/connectivity and the distribution of reservoir quality variation, in order to know and deliniate prospect area and locating the new wells in the right position. Through the high resolution sequence stratigraphy correlation, the integrated subsurface interpretation especially of zone J-20 could be expected. Sand reservoir of zone J-20 is the objective of this research that produces large amount of oil. The research started with reviewing biostratigraphic data for the age and depositional environment, reviewing core data and well log calibration, defining the facies model by reviewing core, constructing the startigraphic markers and well log analysis well by well. Structural interpretation on seismic combined with well marker guidance. After that, all of the wells correlated using sequence stratigraphic framework to know facies changes relationship laterally or vertically, then facies and depth structural mapping come on next. Porosity and facies modeling using three dimensional model is the final product of this study. The result of this study shows that the study interval is having age in Late Miocene-Pliocene, whilst its deposition environment ranging from and litoral to supralitoral. Typical facies of zone J-20 is channel with two possibility facies association; there are fluvial channel and distributary channel, both deposited in fluvial and upper delta plain environment. There are two body sand in north and south area, both of them treding NE-SW direction. However, the south sand channels turn to the SE direction and became thick. Based on structural map, there are anticline structures trending NE-SW and six normal listric fault. These faults cut the area into eight compartments, but only F6 fault in the south affected the sand distribution and thickness of J-20 reservoir along the growth fault. The study area revealed have formed structural and stratigraphic compartementalization and isolating the hydrocarbon distribution. The integration of isopach map, porosity, depth structural map and fluid contact could be used for development strategy of Bunyu Field.