ALFONS, FABYAN MARK (2025) STUDI KARAKTERISTIK DAN PENENTUAN ZONA CLAY CAP DAN RESERVOIR LAPANGAN PANAS BUMI “MFG”, BENGKULU. Skripsi thesis, UPN Veteran Yogyakarta.
![[thumbnail of 1_Skripsi full_111210015_Fabyan Mark Alfons.pdf]](http://eprints.upnyk.ac.id/style/images/fileicons/text.png) |
Text
1_Skripsi full_111210015_Fabyan Mark Alfons.pdf Restricted to Repository staff only Download (15MB) |
|
Text
2_Cover_111210015_Fabyan Mark Alfons.pdf Download (93kB) |
|
Text
3_Abstrak__111210015_Fabyan Mark Alfons.pdf Download (197kB) |
|
Text
4_Halaman Pengesahan__111210015_Fabyan Mark Alfons.pdf Download (52kB) |
|
Text
5_Daftar Isi__111210015_Fabyan Mark Alfons.pdf Download (230kB) |
|
Text
6_Daftar Pustaka__111210015_Fabyan Mark Alfons.pdf Download (198kB) |
Abstract
ABSTRAK
STUDI KARAKTERISTIK DAN PENENTUAN ZONA CLAY
CAP DAN RESERVOIR LAPANGAN PANAS BUMI “MFG”,
BENGKULU
Oleh
Nama Fabyan Mark Alfons
NIM: 111.210.015
(Program Studi Sarjana Teknik Geologi)
Lapangan Panas Bumi "MFG" di Kabupaten Lebong, Bengkulu, yang dikelola PT
Pertamina Geothermal Energy Tbk., menunjukkan ketidaksesuaian antara model
konseptual eksisting dengan data terbaru, khususnya dalam penentuan batas clay
cap dan reservoir. Studi sebelumnya menunjukkan bahwa pendekatan berbasis
temperatur saja tidak cukup akurat, sehingga diperlukan integrasi data geofisika dan
sumur terkini untuk memperbaiki model sistem panas bumi.
Penelitian ini menggunakan metode kualitatif dengan analisis data sekunder dari
PT Pertamina Geothermal Energy Tbk., meliputi: (1) geokimia fluida manifestasi
untuk menentukan tipe fluida dan suhu reservoir, (2) interpretasi data
magnetotelurik (MT) untuk identifikasi resistivitas bawah permukaan, (3) evaluasi
data sumur (stratigrafi, alterasi, lost circulation, serta tekanan dan temperatur), dan
(4) sintesis data untuk membangun model konseptual terbaru. Integrasi data 3G
(geologi, geokimia, geofisika) dan uji sumur dilakukan untuk memvalidasi
batas clay cap dan reservoir.
Hasil penelitian menunjukkan bahwa sistem panas bumi "MFG" merupakan sistem
vulkanik bersuhu tinggi (±300°C) dengan dominasi air. Zona clay cap berasosiasi
dengan alterasi smektit pada batuan tufa dan breksi tufa (Upper Suban Agung
Volcanic). Nilai resistivitas akurat dalam penentuan clay cap karena sesuai dengan
data sumur (<10 Ωm). Sedangkan reservoir (suhu 250-300°C) dicirikan oleh
alterasi epidot pada batuan lava andesit (Hululais Volcanic) dan dikontrol oleh
permeabilitas sekunder dari Sesar Normal Cemeh dan Sesar Dekstral Agung Hilir.
Nilai resistivitas tidak dapat mendeliniasi batas reservoir dengan akurat. Revisi
model mengungkap aliran fluida dari upflow di selatan (Khuluk Beriti)
ke outflow di utara (Semelako), dengan sumber panas berupa intrusi granodiorit.
Hasil ini memperbaiki ketidakakuratan model sebelumnya dan memberikan
rekomendasi untuk eksplorasi lanjutan.
Kata kunci: alterasi hidrotermal, clay cap, magnetotelurik, panas bumi, reservoir.
vii
ABSTRACT
STUDY OF CHARACTERISTICS AND DETERMINATION OF
CLAY CAP AND RESERVOIR ZONES IN THE "MFG"
GEOTHERMAL FIELD, BENGKULU
By
Fabyan Mark Alfons
NIM: 111210015
(Geological Engineering Undergraduated Program)
The "MFG" Geothermal Field in Lebong Regency, Bengkulu, operated by PT
Pertamina Geothermal Energy Tbk., shows discrepancies between existing
conceptual models and actual data, particularly in defining clay cap and reservoir
boundaries. Previous studies by Dwikorianto et al. (2023) demonstrated that
temperature-based approaches alone are insufficiently accurate, necessitating the
integration of recent geophysical and well data to improve the geothermal system
model.
This study employs qualitative methods using secondary data from PT Pertamina
Geothermal Energy Tbk., including: (1) fluid geochemistry of surface
manifestations, (2) magnetotelluric (MT) data interpretation for subsurface
resistivity mapping, (3) well data evaluation (stratigraphy, alteration, lost
circulation, and pressure-temperature measurements), and (4) data synthesis to
develop an updated conceptual model. Integration of 3G data (geology,
geochemistry, geophysics) and well tests was conducted to validate clay cap and
reservoir boundaries.
Results indicate that the "MFG" system is a high-temperature (±300°C) volcanic
dominated system with water as the primary fluid. The clay cap correlates with
smectite alteration in tuff and tuff breccia (Upper Suban Agung Volcanic).
Resistivity values accurately determined the clay cap as they matched well data
(<10 Ωm). In contrast, the reservoir (250-300°C), characterized by epidote
alteration in andesite lava (Hululais Volcanic), is controlled by secondary
permeability from the Cemeh Normal Fault and Agung Hilir Dextral Fault.
Resistivity values could not accurately delineate reservoir boundaries. The revised
model reveals fluid flow from the southern upflow (Beriti Volcano) to the
northern outflow (Semelako), driven by granodiorite intrusion. These findings
correct previous model inaccuracies and provide recommendations for further
exploration.
Keywords: geothermal, hydrothermal alteration, magnetotelurik, reservoir, clay
cap.
viii
| Item Type: | Tugas Akhir (Skripsi) |
|---|---|
| Uncontrolled Keywords: | geothermal, hydrothermal alteration, magnetotelurik, reservoir, clay cap. |
| Subjek: | Q Science > QE Geology |
| Divisions: | Fakultas Teknologi Mineral dan Energi > (S1) Teknik Geologi |
| Depositing User: | Eko Yuli |
| Date Deposited: | 21 Oct 2025 02:31 |
| Last Modified: | 21 Oct 2025 02:31 |
| URI: | http://eprints.upnyk.ac.id/id/eprint/44633 |
Actions (login required)
 |
View Item |