Telah dilakukan penelitian untuk mengidentifikasi sebaran bijih besi di Kecamatan Walenrang, Kabupaten Luwu, Sulawesi Selatan dengan menggunakan metoda geolistrik tahanan jenis konfigurasi Wenner-Schlumberger. Hasil survey resistivity berupa penampang 2-D dan blok model 3-D yang memberikan informasi mengenai sebaran bijih besi, dimana penyebaran terbesar berada di sebelah barat daerah penelitian dengan arah timur laut - barat daya. Data resistivitas dari penampang resistivitas 2-D yang diperoleh dari pengukuran lintasan 1 sampai dengan pengukuran lintasan 4 di lapangan yaitu zona lapisan bijih besi magnetite berada pada resistivitas ρ < 40 Ωm, zona pelapukan batuan andesit dengan resistivitas 40 Ωm < ρ < 250 Ωm dan zona batuan basalt dengan resistivitas tinggi ρ > 250 Ωm yang sesuai dengan yang ditemukan bagian barat daerah penelitian yaitu di lembah buntu Mario dan buntu Sikuku hingga ke buntu Andulan bagian utara ada boulder magnetis yang tersebar di aliran sungai lamasi diperkirakan berasal dari zona potasik.

Indonesia is one of the tropical countries that only has two seasons, namely the dry season and the rainy season. The prolonged dry season caused the villagers in Sampakang having difficulties in obtaining clean water sources. This research conducted in Sampakang, Maros, Indonesia aims to obtain groundwater that can be used as a spring for villagers. The research was conducted using the Geoelectrical Resistivity Method Wenner Schlumberger configuration with a total trajectory of 56 m. The results of the analysis showed that the soil structure consists of shallow groundwater and the RMS error is 2.2%. Where the thickness of the aquifer layer is 9 m and was found at a depth of 2.5 m-11.5 m. Aquifer layer in the form of alluvium deposits with a resistivity value of about <10.9 Ωm-100 Ωm. There is a permeable layer in the form of limestone in a depth of 9.6 m with resistivity value at >100 Ωm.

A boundary element method is utilized to find numerical solutions to boundary value problems of exponentially graded media governed by a spatially varying coefficients anisotropic-diffusion convection equation. The variable coefficients equation is firstly transformed into a constant coefficients equation for which a boundary integral equation can be formulated. A boundary element method (BEM) is then derived from the boundary integral equation. Some problems are considered. The numerical solutions justify the validity of the analysis used to derive the boundary element method with accurate and consistent solutions. A FORTRAN script is developed for the computation of the solutions. The computation shows that the BEM procedure elapses very efficient time in producing the solutions. In addition, results obtained from the considered examples show the effect of the anisotropy of the media on the solutions. An example of a layered material is presented as an illustration of the application.

Eksplorasi dan eksploitasi di Indonesia saat ini masih terfokus pada energi konvensional hidrokarbon dibandingkan energi nonkonvensional hidrokarbon seperti gas serpih. Gas serpih adalah salah satu energi nonkonvensional yang kaya material organic dan mencapai kematangan, pada kondisi dan tipe tertentu mampu berfungsi sebagai reservoir minyak dan gas. Jendela awal kematangan pada kedalaman 1200-2200 m  dan kategori tipe kerogen II/III menghasilkan minyak dan gas.

Talang Akar Formation is a proven hydrocarbon source rock in South Sumatra basin. The formation contains dominant shale at the top, with some sandstone interbeds. This study uses 3 crude oil sample and 10 well-cutting obtained from two well (SMT-1 & SMT-2) in Prabumulih oil field. We used biomarkers and carbon isotopes (δ13C) data to determine the paleodepositional environment of Talang Akar Formation. The biomarkers data were obtained from gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analysis of normal alkanes, isoprenoids, triterpene, and steranes. Carbon isotopes (δ13C) include saturated and aromatic fractions. The pristine (Pr) to phytane (Ph) ratio is a good indicator of the depositional environment. Higher values of Pr/Ph ratio i.e. ≥3.0 indicate oxidizing conditions i.e. terrestrial while lower values in the range of 1.0-3.0 suggests siliciclastic-dominated marine conditions. However, very low values i.e. ≤ 1.0 indicate reducing conditions or fresh and brackish water conditions. The results in this research show that Pr/Ph ratios range from 7.90-16.66, characteristic of high wax crude oils, primarily originated in fluviatile and deltaic environment containing a significant amount of terrestrial organic matter. Similarly, the resultant ratios of Pr/n-C17 and Ph/n-C18 in SMT-1 and SMT-2 wells range from 0.91-10.72 and 0.11-1.29 respectively, which reflect that most of kerogen was derived from humic source and tend towards an oxidative environment of deposition. Cross-plot of carbon-13 isotopes (δ13C) shows saturated versus aromatic fraction. The resultant plot indicate a deltaic to marginal marine environment for SMT-2 well and a more marine environment for SMT-1 well. The oil/source rock correlation analysis using biomarker data shows that the oils in Prabumulih field is correlated with the oils in source rock of Talang Akar Formation. This study concludes that the source rock contains abundant humic organic matter that was deposited in a transitional (Fluvio-deltaic) to marginal marine environment under oxic conditions.