JENIS GEOMETRI AKIFER DAERAH TELUK YOUTEFA KOTA JAYAPURA, PROVINSI PAPUA
Shale in the Upper Member of Telisa Formation, Central Sumatra Basin, believed to have characteristics as oil shale. Characteristics of oil shale can be divided into two types, the physical and organic geochemistry characteristics. The physical characteristics consist of lithology and depositiona...
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| Format: | Theses |
| Language: | Indonesia |
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| Online Access: | https://digilib.itb.ac.id/gdl/view/70607 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Shale in the Upper Member of Telisa Formation, Central Sumatra Basin, believed
to have characteristics as oil shale. Characteristics of oil shale can be divided into
two types, the physical and organic geochemistry characteristics. The physical
characteristics consist of lithology and depositional environment, whereas the
organic geochemistry characteristics consist of abundance, type, maturity of
organic material, and number of shale oil that can be generated from a rock
samples.
Data of BH-2 oil shale drilling wells shown a layer of shale in the Upper Member
of Telisa Formation with thickness that reaches 98.5 meters, dark gray-brownish
gray, laminated structure, flake, soft-hard. In some places there are fine-very fine
sandstones, gray, soft-hard.
Maceral analysis performed on shale samples showed that the content of organic
material is dominated by liptinite groups, which is lamalginite and telalginite
(botryococcus) maceral, while small amounts of vitrinite and inertinite present in
the samples. Cross plots between total organic carbon (TOC) and potential yields
(PY) at diagram, shows the abundance of organic material in the shale samples
produce hydrocarbon that categorized as very good-excellent. Cross plot between
HI and OI on the van Krevelen diagram indicate that the type of kerogen shale
samples categorized to type II and III kerogens. Range of vitrinite reflectance
values (Rv) in shale samples are between 0.20 to 0.31%, Tmax range from 429 to
438°C, and CPI value are between 1.05 and 1.04, that can be indicated the shale
samples are immature-early mature. From the analysis carried out from 13
retorting of the shale samples (10 samples from wells BH-2 and 3 samples from
outcrops), indicate the range of oil content from shale samples are between 4-78
l/ton rock, with average of 32 l/ton rock.
Based on data from organic petrography, on samples of shale Upper Member of
Telisa Formation discovered maceral lamalginite, telalginite (botryococcus),
liptodetrinite which is a maceral derived from algae, while the vitrinite maceral
that derived from higher plants (terrestrial). Two tops of the normal alkanes
distribution from gas chromatographic analysis of samples B3-65 (nC17 and
nC27) and B3-89 (nC15 and nC27), indicating that the organic material derived
from algae and higher plants. Cross plots in the diagram pristane/nC17 versus
phytane/nC18 shows that organic material of shale samples derived from algae
and higher plants. The above facts can be interpreted that the organic material
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shale in the Upper Member of Telisa Formation derived from algae and higher
plants.
From the results of maceral analysis, the shale samples discovered botryococcus.
Algae Botryococcus is classified under the submaseral telalginite of maceral
alginite that depositioned in lacustrine environment. The thickness of shale layers
and laminated structures that appear on shale samples are result of the deposition
process in quiet stream condition. From the above facts, it is interpreted that shale
in the Upper Member of Telisa Formation, Central Sumatra Basin is result of
depositional processes in the lacustrine environment. |
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