Analisis Slip Tendency Akibat Reinjeksi Fluida di Zona Húsmúli, Lapangan Panas Bumi Hengill Menggunakan Pemodelan Discrete Fracture Network

Maharani, Jelita Putri (2026) Analisis Slip Tendency Akibat Reinjeksi Fluida di Zona Húsmúli, Lapangan Panas Bumi Hengill Menggunakan Pemodelan Discrete Fracture Network. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Reinjeksi fluida merupakan komponen penting dalam pengelolaan reservoir panas bumi berkelanjutan, namun berpotensi meningkatkan tekanan pori reservoir panas bumi dan memicu reaktivasi rekahan maupun seismisitas terinduksi. Penelitian ini menganalisis potensi reaktivasi rekahan di zona reinjeksi Húsmúli, lapangan panas bumi Hengill, Islandia, melalui integrasi pemodelan Discrete Fracture Network (DFN) dan Slip Tendency Analysis. Model DFN 3D dibangun menggunakan FracMan 8.6 dalam domain 27 km3 dengan total 5,400 rekahan diskrit yang terdistribusi dalam tiga set dominan berorientasi NE-ENE, N-S, dan NW, menghasilkan konektivitas sebesar 99.98% dalam satu kluster tunggal, mengindikasikan jaringan rekahan berada di atas ambang perkolasi. Simulasi aliran fluida berbasis data laju injeksi aktual sumur HN-17 selama 1 tahun (2016) menghasilkan kenaikan tekanan pori sebesar 0.59 MPa. Critical Stress Analysis (CSA) berdasarkan kriteria kegagalan Mohr–Coulomb pada kondisi tegasan in-situ trans-ekstensional menunjukkan seluruh rekahan berada di bawah failure envelope sebelum reinjeksi, mengindikasikan kondisi near-critically stressed secara alami. Kenaikan tekanan pori mengaktivasi 21.9% rekahan menjadi kondisi kritis, dengan hierarki kerentanan NE-ENE > N-S > NW. Hasil penelitian ini memberikan dasar kuantitatif untuk penetapan batas operasional tekanan pori reinjeksi guna memitigasi risiko seismisitas terinduksi pada lapangan panas bumi Hengill dan sistem panas bumi serupa.
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Fluid reinjection is an essential component of sustainable geothermal reservoir management, yet it can elevate reservoir pore pressure and trigger fracture reactivation and induced seismicity. This study analyzes fracture reactivation potential in the Húsmúli reinjection zone of the Hengill geothermal field, Iceland, through integrated Discrete Fracture Network (DFN) modeling and Slip Tendency Analysis. A 3D DFN model was constructed using FracMan 8.6 within a 27 km³ domain, simulating 5,400 discrete fractures distributed across three dominant sets, oriented NE-ENE, N-S, and NW, yielding 99.98% fracture network connectivity within a single connected cluster and indicating the network exceeds the percolation threshold. Fluid flow simulation based on actual injection rate data from well HN-17 over a year (2016) produced a pore pressure increase of 0.59 MPa. Critical Stress Analysis applying the Mohr-Coulomb failure criterion under trans-extensional in-situ stress conditions revealed that all fractures remained below the failure envelope prior to reinjection, confirming a naturally near-critically stressed reservoir state. The pore pressure increase activated 21.9% of fractures to critically stressed conditions, with a reactivation potential hierarchy of NE-ENE > N-S > NW. These results provide a quantitative basis for establishing operational pore pressure limits during reinjection to mitigate induced seismicity risk at the Hengill geothermal field and analogous geothermal systems.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	DFN, slip tendency, reinjeksi geotermal, seismisitas terinduksi ============================================ DFN, slip tendency, geothermal reinjection, induced seismicity.
Subjects:	Q Science > QE Geology > QE538.8 Earthquakes. Seismology
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geophysics Engineering > 33201-(S1) Undergraduate Thesis
Depositing User:	Jelita Putri Maharani
Date Deposited:	23 Jul 2026 02:08
Last Modified:	23 Jul 2026 02:08
URI:	http://repository.its.ac.id/id/eprint/136314

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