GEOMETRY EVALUATION AND FAULT SYSTEM OF TARAKAN SUBBASIN USING GRAVITY DATA
The latest survey of gravity data using aircraft covering the Tarakan Subbasin area is a significant additional data because there is no direct measured gravity data offshore of North Kalimantan. Evaluation using gravity data, combine with existing seismic and wells data will complement the su...
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| Format: | Theses |
| Language: | Indonesia |
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| Online Access: | https://digilib.itb.ac.id/gdl/view/79364 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | The latest survey of gravity data using aircraft covering the Tarakan Subbasin area is
a significant additional data because there is no direct measured gravity data offshore
of North Kalimantan. Evaluation using gravity data, combine with existing seismic and
wells data will complement the subsurface evaluation of the Tarakan Sub-basin area to
be more certain.
The gravity data that has been processed to obtain Bouguer corrected gravity data is
analysed to obtain geometry and trends of the geological structures in the Tarakan Subbasin. Gravity data analysis was also carried out to obtain differences in the separation
of fault systems in the Tarakan Sub-basin based on the lineament trends of the gravity
data. The stages in the research are using gravity data, 2D seismic and rock density
data from wells which are used as a reference for rock density values. Separation of
deep and shallow source gravity anomalies is carried out using frequency spectrum
analysis obtained for the estimated depth of 12km for deep while for shallow sources
5km, attributes of First Vertical Derivative (FVD) and Total Horizontal Gradient
(THG) gravity data. The seismic data of the study area which has been calibrated with
the well data is interpreted to obtain a depth structure map for each geological stage.
The source gravity anomaly map in providing an irregular shape geometry of the
Tarakan Subbasin is irregular ellips with the south-eastern boundaries cannot be
identified because its has connected with Sulawesi Sea.The THG attribute gravity
anomaly data can be used to interpret the direction of continuity of geological
structures with boundaries and differences in fault systems that can be better separated.
The direction of continuity of the structure trending Northwest - Southeast is correlated
with strike- slip faults while the direction of continuity of the structure trending
Northeast - Southwest is correlated with normal faults and growth faults. The results
of rock density modeling using gravity data can be used to estimate the depth of
basement with an estimated depth of basement ranging up to 9km with basement is
modelled as a transitional of continental crust and oceanic crust |
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