Kinetic modeling of the Pematang-Sihapas(!) petroleum system, Malacca Strait PSC, Central Sumatra

2018 ◽  
Author(s):  
R.C. Davis
Author(s):  
Muchamad Ocky Bayu Nugroho ◽  
Carolus Prasetyadi ◽  
Teguh Jatmiko

<p>Lokasi Penelitian terletak di Selat Malaka dan termasuk dalam Cekungan Sumatra Tengah. Secara stratigrafi, Batuan Dasar Cekungan Sumatra Tengah berumur Pra Tersier dengan litologi batuan sedimen yang termalihkan atau metasedimen. Berdasarkan data sumur pemboran, batuan dasar di lokasi penelitian secara umum berupa kuarsit dan filit. Rekahan pada batuan dasar dikontrol oleh periode tektonik regional yang mempengaruhi Sumatra. Sesar-sesar yang terbentuk berarah umum Utara Barat Laut – Selatan Tenggara (NNW – SSE), hasil dari fase tektonik selama Paleogen hingga Neogen yang menghasilkan morfologi batuan dasar beragam akibat adanya horst graben dan half graben. Morfologi tinggian adalah yang berpotensi menjadi reservoir karena batuan induk yang terletak lebih rendah akan memungkinkan migrasi hidrokarbon. Identifikasi rekahan batuan dasar dianalisa berdasarkan data pemboran sumur dan seismik. Intensitas rekahan dibangun berdasarkan model dengan pendekatan 4 parameter geologi yaitu intensitas rekahan dengan jarak dari bidang sesar, intensitas rekahan dengan pucak antiklin, intensitas rekahan dengan jarak dari permukaan batuan dan dibantu dengan atribut seismik. Nilai intensitas yang memungkinkan terbentuk rekahan adalah 0,3-1.</p><p><em>The research site is located in the Malacca Strait and is included in the Central Sumatra Basin. Stratigraphically, the basement of the Central Sumatra Basin is Pre-Tertiary with thermal sedimentary or metasediment lithology. Based on data from drilling wells, bedrock in the study site generally consists of quartzite and filite. Fractures in bedrock are controlled by regional tectonic periods affecting Sumatra. Faults that form are generally north-north-south-south (NNW-SSE), resulting from tectonic phases during Paleogene to Neogene which produce various bedrock morphologies due to horst graben and half graben. Height morphology is the potential to be a reservoir because the source rock which is located lower will allow hydrocarbon migration. Identification of basement fractures was analyzed based on well and seismic drilling data. The fracture intensity was built based on the model with a 4 geological parameter approach, namely fracture intensity with distance from the fault plane, fracture intensity with anticline peaks, fracture intensity with distance from the rock surface and assisted with seismic attributes. The intensity value that allows the fracture to form is 0.3-1.</em></p>


Author(s):  
B., M. Hartono

Biomarker analyses can provide information about the source of organic matter, depositional environment, and maturity of source rock that is very useful for basin evaluation and understanding the petroleum system. In this paper, the study focuses on biomarker characterization of the Kelesa Formation that is situated in the Central Sumatra Basin, one of the petroliferous basins in Indonesia. This Eocene formation is equivalent to the Pematang Formation that is well known as acting as source rock in the Central Sumatra Basin. Thirty fresh outcrop samples were taken for biomarker analysis, with specification fourteen samples for gas chromatography and sixteen samples for gas chromatography-mass spectrometry. The gas chromatography analysis was done with a Perkin Elmer Clarus 600 type instrument while the mass spectrometry was done using a Perkin Elmer Clarus SQ 8C instrument. The results show that the organic matter dominantly comes from terrestrial plants with minor input from planktonic algae. Moreover, possible Botryococcus braunii input in the sediment suggests that the Kelesa Formation has been deposited in a lacustrine environment. Since the Kelesa Formation was deposited in a lacustrine environment, this formation is expected to be highly oil-prone source rock. The maturity biomarker indicators suggest that the formation does not reach appropriate maturity to expel hydrocarbon. However, the formation still has very good potential for oil shale resources. This study supports the previous study in the Kelesa Formation, and improves the understanding of the depositional history of the Kelesa Formation and the potential of the Kelesa Formation as oil shale resources. Moreover, the authors hope that this study can support recent basin evaluation and improve the understanding of the petroleum system in the Central Sumatra Basin.


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