Geological Structure Delineation Based on Forward Modeling and Inversion Using Gravity Methods at the Gemah Field, South Sumatra Basin

Putri Yulia Riska; Rintan Ayu Novitasari; Rizka Rizka

doi:10.20527/flux.v24i1.26973

Geological Structure Delineation Based on Forward Modeling and Inversion Using Gravity Methods at the Gemah Field, South Sumatra Basin

Putri Yulia Riska, Rintan Ayu Novitasari, Rizka Rizka

Abstract

The Gemah Field is one of the exploration areas located in the South Sumatra Basin, which exhibits complex geological structures resulting from regional tectonic activity and is one of Indonesia’s key hydrocarbon-producing basins. This study aims to delineate subsurface structures and construct a geological model based on the analysis of gravity data using forward modeling and inversion methods. The data used consist of processed GGMPlus satellite gravity data to obtain Complete Bouguer Anomaly (CBA) values. The processing steps included Bouguer correction, rock density estimation, spectral analysis to estimate the depth of the anomaly source, separation of regional and residual anomalies, and the application of enhancement methods such as Total Horizontal Derivative (THD), Tilt Derivative (TDR), and Tilt Derivative of Horizontal Gradient (TDX) to clarify the boundaries of subsurface structures. The analysis results indicate that the gravity anomaly patterns in the study area are controlled by variations in rock density associated with the presence of geological structures such as faults and changes in subsurface stratigraphic configuration. Modeling results reveal a subsurface stratigraphic sequence consisting of Quaternary Volcanic Rocks, the Muara Enim Formation, the Air Benakat Formation, and the Gumai Formation. This research is recommended to support hydrocarbon exploration and identify optimal well locations. It addresses a gap in previous studies—which lacked a comprehensive integration of enhancement methods and spectral analysis—with the aim of providing a more accurate picture of subsurface conditions.

Keywords

Gravitational Anomalies; South Sumatra Basin; Forward Modeling; Hydrocarbons; Gravitational Inversion

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References

Adhani, A. T., Meidina, Z., Wibowo, R. C., & Anggitarizka, M. (2022). Forward Modelling pada Anomali Gayaberat Model Fault Menggunakan Matlab Mathworks. Jurnal GeoCelebes, 6(2), 86–95. https://doi.org/10.20956/

geocelebes.v6i2.1915

Alfayed, M. R. D., Siregar, Y., Ramadani, D. N., Syaifudin, M., & Setiawan, J. (2025). Characteristic of the Source Rock Of The Lahat and Talang Akar With Crude Oil In Sarolangun, Jambi sub-basin, Indonesia. Journal of Geoscience, Engineering, Environment, and Technology, 10(4), 535–543. https://doi.org/10.25299/jgeet. 2025.10.4.17999

Coelho, A. C. Q. M., Menezes, P. T. L., & Mane, M. A. (2021). Gravity Data as a Faulting Assessment Tool for Unconventional Reservoirs Regional Exploration. Journal of Natural Gas Science and Engineering, 94, 104077. https://doi.org/

1016/j.jngse.2021.104077

Cooper, G. R. J., & Cowan, D. R. (2006). Enhancing potential field data using filters based on the local phase. Computers & Geosciences, 32, 1585–1591. https://doi.org/10.1016/j.cageo.2006.02.016

Darmawati, D. E., & Setiawan, A. (2021). Pemodelan struktur bawah permukaan Gunungapi Lokon dan Soputan menggunakan pemodelan inversi 3D berdasarkan data gravitasi GGMplus. Jurnal Fisika Indonesia, 25(1), 16–22.

https://doi.org/10.22146/jfi.v25i1.60649

Elhussein, M. (2021). New Inversion Approach for Interpreting Gravity Data Caused by Dipping Faults. Earth and Space Science, 8(3), e2020EA001075.

https://doi.org/10.1029/2020EA001075

Hakim, Y. U. Al, Arman, Y., & Zulfian, Z. (2023). Pemodelan Inversi Metode Gravitasi Menggunakan Simulated Annealing. Jurnal Fisika Unand, 12(2), 261–267. https://doi.org/10.25077

/jfu.12.2.261-267.2023

Jing, L., Yang, Y., Yao, C., Qiu, L., Chen, D., & Xu, M. (2022). Detection of Geological Boundaries by 3D Gravity Inversion for Density Gradients in Different Directions. Frontiers in Earth Science, 10, 967771. https://doi.org/10.3389/

feart.2022.967771

Kamila, P., Herida, S., Praptono, A., Sunardi, E., & Andriana, Y. (2023). Determination of Hydrocarbon Zone and Depositional Environment Facies in Talang Akar Formation, South Sumatra Basin at “Epura” Field. Journal of Geological Sciences and Applied Geology, 7(2), 13–20.

https://doi.org/10.24198/gsag.v7i2.50361.

Kausarian, H., Redyafry, Lady, Tetuko, J., Sumantyo, S., Suryadi, A., & Lubis, M. Z. (2023). Structural Analysis of the Central Sumatra Basin Using Geological Mapping and Landsat 8 OLI/TIRS C2 L1 Data. EVERGREEN Joint Journal of Novel Carbon Resource Sciences & Green Asia Strategy, 10(2), 792–804. https://doi.org/

5109/6792830

Liu, S., Hu, X., Fedi, M., Baniamerian, J., Abbas, M. A., & Chauhan, M. S. (2025). Petrophysical and Geophysical Constrained Inversion of Gravity Data Based on Starting and Referenced Models. Journal of Geophysics and Engineering, 22(1), 36–47.

https://doi.org/10.1093/jge/gxae111

Minakov, A., & Gaina, C. (2021). Probabilistic Linear Inversion of Satellite Gravity Gradient Data Applied to the Northeast Atlantic. Journal of Geophysical Research: Solid Earth, 126(8), e2021JB021854.

https://doi.org/10.1029/2021JB021854

Nugraha, G. U., Lumban Gaol, K., Handayani, L., & Lubis, R. F. (2021). Lineament Extraction Using Gravity Data in the Citarum Watershed. Indonesian Journal of Geography, 53(1), 87–94.

https://doi.org/10.22146/ijg.52402

Pham, L. T. (2020). A Comparative Study on Different Filters for Enhancing Potential Field Source Boundaries: Synthetic Examples and a Case Study from the Song Hong Trough (Vietnam). Arabian Journal of Geosciences, 13, 723.

https://doi.org/10.1007/s12517-020-05737-5

Pirdaus, R. M., Muhardi, & Perdhana, R. (2025). Pemodelan 2D Struktur Geologi Bawah Permukaan Daerah Lumbang Rarat, Tapanuli Utara, Berdasarkan Data Gravitasi GGMPlus 2013. Jurnal Geosains dan Teknologi, 8(1), 16–23.

https://doi.org/10.14710/jgt.8.1.2025.16-23

Ramadhani, A., Sanjaya, E., & Purba, H. (2021). Identifikasi Struktur Bawah Permukaan Lapangan Banyuasin dengan Menggunakan Pemodelan 2.5D Data Gravitasi dan Implikasinya terhadap Petroleum System. Lembaran Publikasi Minyak dan Gas Bumi, 56(1), 1–14. https://doi.org/10.29017/

LPMGB.56.1.919

Rinanda, S. T. (2024). Identification of the Subsurface Structure of the Great Sumatra Fault Dikit Segment Based on FHD, SVD, and Forward Modelling Analyses. Jurnal Geofisika, 22(2), 95–108.

https://doi.org/10.36435/jgf.v22i2.631

Roy, A. (2021). Gravity Inversion of 2D Fault Having Variable Density Contrast Using Particle Swarm Optimization. Geophysical Prospecting, 69(8), 2143–2159. https://doi.org/10.1111/1365-2478.13094

Sarkowi, M., Wibowo, R. C., Minardi, S., & Arifianto, I. (2021). Identification of Hydrocarbons Sub-Basin Based on Gravity Data Analysis in Lampung Area. Jurnal Penelitian Fisika dan Aplikasinya, 11(2), 106–113.

https://doi.org/10.26740/jpfa.v11n2.p106-113

Sudrajad, B., Sutarman, T., Sinaga, E. S., & Ngaderman, H. (2024). Identification of Jayapura Seismo-Tectonic Fault Based on 3D Inverse Modeling of Gravity Data. Jurnal Geofisika Eksplorasi, 10(1), 47–64.

https://doi.org/10.23960/jge.v9i2.372

Syaifudin, M., & Subroto, E. A. (2024). Geochemical Characterizations of Crude Oils in Pendopo High and Limau Graben, South Sumatra Basin. Indonesian Journal on Geoscience, 11(1), 1–13.

https://doi.org/10.17014/ijog.11.1.1-13

Zhong, Y., Ren, Z., Tang, J., Lin, Y., Chen, B., Deng, Y., & Jiang, Y. (2022). Constrained Gravity Inversion with Adaptive Inversion Grid Refinement in Spherical Coordinates and Its Application to Mantle Structure Beneath Tibetan Plateau. Journal of Geophysical Research: Solid Earth, 127(5), e2021JB022916. https://doi.org/10.1029/2021JB02291

DOI: http://dx.doi.org/10.20527/flux.v24i1.26973