The presence of authigenic clay minerals is usually found in sandstones where these minerals grow in the environment itself. Authigenic clay minerals provide benefits to sandstones, especially to determine the quality of porosity and permeability in sandstones. The samples in this study were collected from an outcrop of measured section at Cipamingkis’ River. The main goal of this study was to understand the presence of authigenic clay minerals in sandstones caused by the diagenetic process using Scanning Electron Microscope and Energy Dispersive X-Ray (SEM – EDX method. The results of this study were kaolinite, smectite, and illite found in very dominant amounts in sandstones as pore linings, pore fillings, replacement, and vug fillings.

Indonesia’s tectonic activity is one of the most active in the world. These conditions make Indonesia prone to earthquakes, tsunamis, and volcanic eruptions. Tsunamis are large ocean waves that are formed through several processes such as underwater earthquakes, underwater landslides, volcanic activity, and asteroid impacts. Indonesia has been hit by various tsunami events. However, not all characteristic tsunami events are well known and recorded. Knowing the characteristics of a tsunami occurrence is very important to understand the frequency and intensity of tsunamis in the present. This research create a WebGIS database for paleotsunami in Indonesia. Tsunami incident data comes from literature related to tsunami events such as books, journals, reports, final projects, and others. Making WebGIS in this study will be developed using website programming, namely HTML, CSS, and JavaScript. The research results obtained 302 tsunami data. The period of tsunami in this research is from Late Miocene to the last tsunami in 2018. The WebGIS created presents a database of tsunami events in Indonesia, a dashboard of Indonesian tsunami statistics, and a tsunami learning educational feature. It is hoped that the results of this database will serve as a means of information for future paleotsunami research needs and as a means of education regarding the potential for tsunamis in Indonesia.

The Upstream Cibeet sub-watershed is part of the Citarum watershed and Cibeet sub-watershed with an area of 69.35 km2. Hydrologically, the upstream part of the watershed usually functions as a recharge area, and its development should be geared towards land conservation and erosion mitigation. Parameters of rainfall, soil type and texture, geology, lineament density, drainage density, geomorphology, and land cover are used in predicting the most potential catchment area. Thematic maps were made for each parameter. Weighting is carried out using the Analytical Hierarchy Process (AHP) with the following results: rainfall 0 %, soil type and texture 34.62 %, geology 24.98 %, lineament density 17.66 %, drainage density 8.57 %, geomorphology 9.34 %, and land cover 4.83 %. The integration of each thematic map resulted in a map with four zonations, namely zone of poor (4.93 %), fair (32.67 %), good (60.58 %), and very good (1.81 %) recharge potential. Based on the groundwater table contour, groundwater mimics the surface topography and flows from the south to the north and northeast part of the study area. Geological structures in the study area possess a NE-SW and NW-SE trend with a normal oblique regime. Structural damage zones are predicted to function as conduits for water movement, especially in volcanic and intrusion lithology.

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Low-resistivity & low-quality reservoir has been successfully developed in ONWJ area by using hydraulic fracturing stimulation method to optimize production gain due to low-permeability reservoir property. The purpose of this research is to understand implication of shale structure for increasing gain production after hydraulic fracturing stimulation. Implementation of hydraulic fracturing was first completed at BerylE-1 and the well could produce 455 BOPD at 560 psi in reservoir 33 and 35. This reservoir was found in Upper Cibulakan Formation that consists of various lithology’s such as very fine-grained sandstone, shale, siltstone & thin tight carbonate that deposited in shallow marine neritic to littoral environment. Production anomaly occurs after hydraulic fracturing stimulation. Some of well in this reservoir show good incremental production, but in the other well there was no significantly incremental production in this reservoir. There were three types of shale structure classification based on effective porosity distribution: laminated shale, structural shale and dispersed shale. Shale structure for each well has been defined based on Thomas Stieber plot and calibrated using petrographic analysis from 8 sample depth point. Based on this method, reservoir 33 is dominated by structural shale while reservoir 35 is dominated by laminar shale. Production data and shale type from each well has been compared and it shows that hydraulic fracturing simulation will increase effective porosity and will also increase effective permeability value. In BerylD-1 well hydraulic fracturing only completed in reservoir 35 and produced 340 BOPD with initial water cut 0 %. Laminar shale that dominates in reservoir 35 has high factor to increasing production gain after hydraulic fracturing was applied. Release of clay that caused by hydraulic fracturing will increase effective porosity and permeability.