Pemetaan Penyebaran Batubara Di Lapangan “X” Dengan Metode Geolistrik Resistivitas Berdasarkan Validasi Data Bor

Setijawan, Vega (2025) Pemetaan Penyebaran Batubara Di Lapangan “X” Dengan Metode Geolistrik Resistivitas Berdasarkan Validasi Data Bor. Other thesis, Institut Teknologi Sepuluh Nopember.

Text 5017211061-Undergraduate_Thesis.pdf - Accepted Version Restricted to Repository staff only Download (6MB) | Request a copy

Abstract

Batubara merupakan sumber energi fosil penting di Indonesia, terutama di daerah penghasil seperti Formasi Lemau di Bengkulu yang terdiri atas batulempung, batupasir, serta lapisan batubara. Penelitian ini menggunakan metode resistivitas geolistrik 2D untuk mengidentifikasi persebaran batubara dengan validasi melalui data bor. Metode geolistrik dipilih karena kepekaannya mendeteksi perbedaan sifat kelistrikan pada lapisan batuan, di mana batubara dan batulempung yang jenuh air cenderung menunjukkan resistivitas rendah. Survei geolistrik menggunakan konfigurasi elektroda Wenner-Schlumberger menghasilkan profil resistivitas 2D pada 15 lintasan survei sepanjang 282 meter dengan jarak elektroda 6 meter. Dalam penerapannya, arus listrik dialirkan ke dalam tanah melalui dua elektroda arus yang ditempatkan pada posisi terluar dalam susunan konfigurasi pengukuran. Data hasil survei geolistrik akan dikalibrasi terhadap data bor yang telah ada untuk memperoleh gambaran 2D serta 3D distribusi batubara. Proses inversi data menghasilkan model resistivitas dengan RMS error rendah (3-30%). Hasil inversi menunjukkan rentang resistivitas 7,06-1.168,64 ohm.m. Nilai resistivitas rendah (7-23 ohm.m) terdeteksi pada lapisan yang diduga berupa shale-batubara jenuh air, sedangkan zona resistivitas sedang (23,5-100 ohm.m) mengindikasikan batu lempung (batulempung), dan nilai resistivitas tinggi (100-1.168 ohm.m) dihubungkan dengan batupasir atau lapisan tanah penutup. Berdasarkan data bor, lapisan atas (5-8 m) dan lapisan bawah (20-24 m) pada area penelitian dikonfirmasi sebagai lapisan batubara, sedangkan lapisan menengah (8-20 m) merupakan shale-batubara. Nilai resistivitas rendah pada zona shale-batubara (sekitar 7-23 ohm.m) diduga dipengaruhi oleh jenuh air yang tinggi dan tingginya kandungan lempung. Temuan ini mengonfirmasi korelasi antara anomali resistivitas rendah dengan keberadaan lapisan batubara dan lapisan pendukungnya di bawah permukaan. Hasil studi menunjukkan bahwa integrasi metode geolistrik resistivitas dan data bor efektif memetakan distribusi lapisan batubara sesuai dengan stratigrafi Formasi Lemau.
========================================================================================================================================
Coal is a vital fossil energy resource in Indonesia, especially in coal-producing regions such as the Lemau Formation in Bengkulu, which comprises claystone, sandstone, and coal seams. This study employs the 2D geoelectrical resistivity method to identify the distribution of coal, validated through borehole data. The geoelectrical method was chosen for its sensitivity in detecting variations in the electrical properties of rock layers, where coal and water-saturated claystone generally exhibit low resistivity. The geoelectrical survey used a Wenner-Schlumberger electrode configuration, producing 2D resistivity profiles across 15 survey lines, each 282 meters long with 6-meter electrode spacing. In practice, electrical current is introduced into the ground through two current electrodes positioned at the outermost points of the measurement configuration. The data inversion process produced resistivity models with low RMS error (3-30%). The inversion results showed a resistivity range of 7.06-1,168.64 ohm.m. Low resistivity values (7-23 ohm.m) were detected in layers suspected to be water-saturated shale-coal, while medium resistivity zones (23.5-100 ohm.m) indicated claystone, and high resistivity values (100-1,168 ohm.m) were associated with sandstone or overburden layers. Based on borehole data, the upper layer (5-8 m) and the lower layer (20-24 m) in the study area were confirmed to be coal seams, while the middle layer (8-20 m) consisted of shale-coal. The low resistivity values in the shale-coal zone (around 7-23 ohm.m) are believed to be influenced by high water saturation and significant clay content. These findings confirm a correlation between low resistivity anomalies and the presence of coal seams and their supporting layers beneath the surface. The results of the study indicate that the integration of the geoelectrical resistivity method and borehole data is effective in mapping the distribution of coal seams in accordance with the stratigraphy of the Lemau Formation.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Geolistrik Resistivitas, Coal, ShaleCoal, Validasi Data Bor, Sebaran Batubara
Subjects:	Q Science > QC Physics > QC665.E38 Electric fields. Q Science > QE Geology > QE601 Geology, Structural
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User:	Vega Setijawan
Date Deposited:	25 Jul 2025 04:15
Last Modified:	25 Jul 2025 04:15
URI:	http://repository.its.ac.id/id/eprint/121692

Actions (login required)

View Item