Thermal Distribution Pattern of Jaboi Geothermal, Sabang with 2D Numerical Approach - Nanda Gristina; Muhammad Isa; Muksin Muksin (Journal of Aceh Physics Society, 2018)
Telah dilakukan pemodelan numerik menggunakan teknik beda hingga berdasarkan algoritma Gauss – Seidell. Penelitian ini bertujuan untuk menjelaskan proses transfer panas kasus steady state lapangan geotermal Jaboi, Sabang dengan menggunakan parameter fisis nilai konduktivitas termal material. Teknik ini berfungsi mendapatkan model sebaran suhu kemudian dibandingkan terhadap literatur. Teknik ini sesuai untuk struktur geologi kompleks seperti daerah penelitian. Pengujian sensitivitas sebelum memodelkan daerah geotermal Jaboi dilakukan untuk melihat efek geometri daerah geotermal dengan perubahan parameter masukan nilai konduktivitas dan syarat batas terhadap algoritma numerik yang dipakai. Dari hasil pengujian model sintetis sederhana diketahui bahwa litologi lapisan–lapisan batuan bawah permukaan mempengaruhi pola distribusi temperatur yang dihasilkan. Semakin tinggi konduktivitas termal batuan maka semakin tinggi distribusi temperatur yang akan dihasilkan. Berdasarkan hasil penelitian pola distribusi suhu model geologi daerah Jaboi, diperkirakan lapisan batuan berpotensi sebagai top reservoir berada di kedalaman 1000 m dengan perolehan temperatur sekitar 240oC di kedalaman 1050 m. Hasil perhitungan numerik memperkiraan temperatur maksimum di kedalaman 800 m dan kedalaman 900 m masing–masing sebesar 135oC dan 173oC, mengingat skala model bukan skala peta sebenarnya. Numerical modeling has been done using finite difference techniques based on the Gauss-Seidell algorithm. The purpose of this study was to explain the heat transfer process in the case of the steady state of Jaboi geothermal field, Sabang by using the physical parameters of the material's thermal conductivity value as input. This technique is to obtain a temperature distribution model, then compare it to the literature. This technique is suitable for complex geological structures such as the study area. Sensitivity testing before modeling the Jaboi geothermal area is done to see the geometrical effect of the geothermal area by changing input parameters of conductivity values and boundary conditions. The results of the simple synthetic model testing show that the lithology of the subsurface rock layers affects the temperature distribution pattern produced. The higher the thermal conductivity of the rock, the higher the temperature distribution will be produced. Based on the results of the study of the temperature distribution pattern of the Jaboi regional geological model, it is estimated that the rock layer has the potential as a top reservoir at a depth of 1000 m, with a temperature of around 240oC at a depth of 1050 m. The results of numerical calculations estimate the maximum temperature at a depth of 800 m and a depth of 900 m with respectively 135oC and 173oC, considering the scale of the model is not the actual map scale.Keywords: geothermal, modeling, reservoir, caprock, boundary condition