Document Type : Research Article
Authors
1
Geophysical Engineering Study Program, Faculty science and technology, Jambi University, Jl. Jambi - Muara Bulian Km. 15 36361, Jambi, Indonesia.
2
Meteorology, Climatology and Geophysics Agency, Jl. Harapan Saumlaki, Kabupaten Kepulauan Tanimbar. 97464, Maluku. Indonesia
3
Research Center for Geospatial - National Research and Innovation Agency, Jl. Raya Bogor KM.46 Cibinong 16911, Bogor. Indonesia
4
Research Center for Geospatial, National Research and Innovation Agency, Cibinong, Indonesia
Abstract
A sedimentary basin is a geological depression in which sedimentary deposits accumulate over time, creating potential reservoirs for the accumulation and maturation of sediments containing hydrocarbons. Among the various sedimentary basins in Indonesia, the Bengkulu Basin stands out as one of the significant forearc basins. This basin exhibits promising signs of hosting hydrocarbon reserves, exemplified by the presence of an oil show in the Padang Capo village. To further explore and identify potential hydrocarbon traps within the Bengkulu Basin, the gravity method has been employed as a valuable geophysical tool. The gravity method is a commonly used technique in geophysical studies, allowing researchers to investigate the subsurface structure, bedrock composition, rock intrusions, and sedimentary basins by measuring variations in the Earth's gravitational field caused by lateral density differences. These variations are known as gravitational anomalies, and their analysis can provide critical insights into the presence of hydrocarbon traps. In this study, two derivative analyses, namely the First Horizontal Derivative (FHD) and the Second Vertical Derivative (SVD) graphs, were conducted along with 2D modeling using forward modeling. The findings from the analysis of the FHD and SVD graphs, combined with the 2D modeling results, demonstrated a consistent and synchronous outcome. The study area exhibited numerous fault structures and folds, with the dominant fault type identified as rising faults. These structures play a crucial role in the potential trapping of hydrocarbons within the basin. Moreover, the 2D modeling conducted in the vicinity of the oil show revealed the presence of a rising fault structure, along with anticline and syncline structures, all of which possess the attributes necessary to act as efficient hydrocarbon traps. The integration of multiple geophysical techniques in this research has proven valuable in enhancing the understanding of the subsurface geology and identifying potential hydrocarbon reservoirs within the Bengkulu Basin. The presence of an oil show in Padang Capo village served as a significant indicator, motivating the exploration efforts to uncover additional hydrocarbon reserves in the basin. By employing the gravity method and derivative analysis, geologists and geophysicists were able to visualize the fault systems and fold structures that could act as potential traps for hydrocarbons. The successful application of these geophysical techniques in the Bengkulu Basin serves as an essential case study for further exploration efforts in other sedimentary basins in Indonesia and beyond. Accurate identification and delineation of hydrocarbon traps are critical steps in the petroleum exploration process, aiding in the sustainable utilization of energy resources. Additionally, this study's outcomes contribute to the broader understanding of the geological processes involved in the formation and preservation of hydrocarbon reservoirs in forearc basins. Such knowledge is crucial for optimizing exploration strategies and ensuring the responsible extraction of hydrocarbons to meet the world's ever-growing energy demands.
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