FACIES AND STRATIGRAPHIC STUDY OF BRANI FORMATION IN TALAWI REGION, WEST SUMATRA
The Brani Formation is a Paleogene to Eocene formation that is part of the Ombilin Basin, West Sumatra. This formation has been the focus of several studies to understand the geological history of the area and its potential as a hydrocarbon reservoir. In this study, detailed facies and stratigraphic...
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| Format: | Final Project |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/86007 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | The Brani Formation is a Paleogene to Eocene formation that is part of the Ombilin Basin, West Sumatra. This formation has been the focus of several studies to understand the geological history of the area and its potential as a hydrocarbon reservoir. In this study, detailed facies and stratigraphic framework analyses of the Brani Formation were conducted. The study aims to identify lithofacies, facies associations, and facies architecture of the Brani Formation in the study area. The Brani Formation investigated is located in the Talawi area, Tanah Datar Regency, West Sumatra. Field data collection used a stratigraphic section measurement method on a 1:100 scale, containing data on thickness, lithofacies, and facies associations, which were then presented in the form of stratigraphic columns. Measurements produced 4 stratigraphic profiles named PAGIAS, SELO-1, SELO-2, and SELO-3. From these four profiles, the Brani Formation in the Talawi area has 4 facies associations: Proximal Subaqueous Fan, Intermediate Subaqueous Fan, Distal Subaqueous Fan, and Basin Plain. Identification of lithofacies codes and facies associations indicates that the depositional environment model of the Brani Formation in the Talawi area is a Subaqueous Fan-Delta System environment. Thin section analysis was carried out on 18 rock samples from different locations to identify rock names and facies components. The rocks identified from microscopic thin section descriptions include arkose, lithic arkose, lithic arenite, feldspathic wacke, and lithic wacke. The porosity of each sample shows relatively poor porosity. The deposition of the Brani Formation at Bukit Pagias is dominated by the relatively thick Proximal Subaqueous Fan facies association consisting of deformed coarse-grained sandstone and open-framework conglomerates. Meanwhile, the deposition of the Brani Formation at Sungai Selo has a complete facies association, namely Proximal Subaqueous Fan, Intermediate Subaqueous Fan, Distal Subaqueous Fan, and Basin Plain. |
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