Aspek Geokimia Organik Minyak Kondensat Lapangan Geragai, Blok Jabung, Sub-Cekungan Jambi

Pandhini, Shafa Tunjung (2025) Aspek Geokimia Organik Minyak Kondensat Lapangan Geragai, Blok Jabung, Sub-Cekungan Jambi. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Telah dilakukan analisis biomarka hidrokarbon alifatik dan aromatik sampel minyak kondensat Geragai, Blok Jabung, Sub-Cekungan Jambi dengan metode fraksinasi dengan Kromatografi Lapis Tipis (KLT) dan Kromatografi Gas–Spektrometri Massa (KG-SM). Hasil identifikasi menunjukkan keberadaan biomarka berupa n-alkana, isoprenoid, seskuiterpenoid, derivat naftalena, derivat fenantrena, derivat bifenil, serta fluorena. Sumber material organik sampel didominasi oleh input alga dan bakteri akuatik, yang ditunjukkan oleh kelimpahan n-alkana rantai pendek, nilai LHCPI sebesar 5,42 (>1), nilai Paq sebesar 0,73, nilai TAR sebesar 0,13 (<1), rasio LMW/HMW sebesar 4,31 (>1). Input alga tersebut dapat berkontribusi terhadap pembentukan n-alkana rantai menengah hingga rantai panjang dalam lingkungan eutrofik. Kontribusi minor dari tumbuhan tingkat tinggi ditunjukkan oleh rasio CPI sebesar 1,04 (>1), keberadaan senyawa kadalena dan 4β(H)-eudesmana. Lingkungan pengendapan menunjukkan minyak kondensat Geragai terendapkan pada lingkungan sub-oksik yang mencerminkan adanya stratifikasi redoks dimana lapisan permukaan air bersifat oksik sedangkan lapisan bawah cenderung sub-oksik hingga anoksik. Hal ini ditunjukkan melalui rasio Pr/Ph >3, rasio n-C31/n-C19 < 0,4 dan n-C29/n-C17 < 1. Rasio n-C17/n-C31 > 1 dan kelimpahan senyawa aromatik marin seperti 9-MP, 1,3-DMP, dan 3,10-DMP menunjukkan dominasi alga dan bakteri akuatik. Nilai OEP <1, LHCPI >1, CPI ~1, MPI-3 >1, DNR >1, serta distribusi isomer aromatik yang substituennya tersubstitusi pada posisi β mengindikasikan sampel minyak kondensat Geragai telah matang secara termal dan memiliki potensi untuk dimanfaatkan sebagai bahan bakar.
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Analysis of aliphatic and aromatic hydrocarbon biomarkers from condensate oil samples from Geragai, Jabung Block, Jambi Sub-Basin has been carried out using fractionation methods with Thin Layer Chromatography (TLC) and Gas Chromatography–Mass Spectrometry (GC-MS). The identification results indicate the presence of biomarkers such as n-alkanes, isoprenoids, sesquiterpenoids, naphthalene derivatives, phenanthrene derivatives, biphenyl derivatives, and fluorene. The source of the organic material in the sample is dominated by algal and aquatic bacterial input, as indicated by the abundance of short-chain n-alkanes, an LHCPI value of 5.42 (>1), a Paq value of 0.73, a TAR value of 0.13 (<1), and an LMW/HMW ratio of 4.31 (>1). This algal input may contribute to the formation of medium to long-chain n-alkanes in eutrophic environments. Minor contributions from higher land plants are indicated by a CPI ratio of 1.04 (>1) and the presence of compounds such as cadalene and 4β(H)-eudesmane. The depositional environment suggests that the Geragai condensate oil was deposited in a sub-oxic setting, reflecting redox stratification where the surface water layer is oxic while the lower layer tends to be sub-oxic to anoxic. This is indicated by a Pr/Ph ratio >3, an n-C31/n-C19 ratio <0.4, and an n-C29/n-C17 ratio <1. The n-C17/n-C31 ratio >1 and the abundance of marine aromatic compounds such as 9-MP, 1,3-DMP, and 3,10-DMP indicate the dominance of algae and aquatic bacteria. OEP <1, LHCPI >1, CPI ~1, MPI-3 >1, DNR >1, as well as the distribution of aromatic isomers with substituents at the β-position indicate that the Geragai condensate oil sample is thermally mature and has the potential to be utilized as fuel.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Fossil Fuel, Biomarkers, Aliphatic fraction, Aromatic fraction, Condensates, Bahan bakar fosil, Biomarka, Fraksi Alifatik, Fraksi Aromatik, Minyak Kondensat
Subjects:	Q Science Q Science > QD Chemistry Q Science > QD Chemistry > QD251.2 Chemistry, Organic. Biochemistry
Divisions:	Faculty of Science and Data Analytics (SCIENTICS) > Chemistry > 47201-(S1) Undergraduate Thesis
Depositing User:	Shafa Tunjung Pandhini
Date Deposited:	07 Aug 2025 01:03
Last Modified:	07 Aug 2025 01:03
URI:	http://repository.its.ac.id/id/eprint/127857

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