Journal of Geoscience, Engineering, Environment, and Technology
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Study of Hydrodynamic Patterns of Tanjung Pasir Banten Waters to Support the NCICD Sea Wall Development Plan
No full textNumerical modeling of hydrodynamics (HD) around the Tanjung Pasir Waters was carried out using MIKE 21 HD Flexible Mesh software to get the current velocity pattern conditions during the west and east monsoons. This activity is to support the NCICD sea wall construction plan. In addition, the results that will be obtained in this modeling are the conditions of the speed and direction of the current in various tidal conditions during spring and neap. The data used in this modeling include wind speed and direction, wave height, wave period, and wave direction. Based on the research that has been done, the validation value of Naotide tidal data on tidal field data is 93.8 %. HD MIKE 21 modeling results on field data have a validation value of 93.4 %. Extract points 4 and 5 which are the northernmost, have the highest current velocity values compared to the other points. In addition, when heading to the high tide phase, both spring and neap conditions, the current velocity value has the highest value
Exploration of The Magnetic Rocks Potential of Mount Penanggungan: A Study of Myth, History, and Its Implications for Educators and Mountaineers
Full text linkThis study explores the potential of magnetic stones on Mount Penanggungan and their relation to history and myths circulating in the community and climbers. This research is important to do in order to minimize the rate of injury caused by fatigue for climbers on this mountain. In addition, aspects of physics and history can be implications for educators to deliver material on the subject. This research uses a qualitative design with the type of case study—data collection methods through observation, interviews, and document studies. The results of this study show that some rocks on Mount Penanggungan, especially when approaching their peak, have a magnetic field anomaly up to 4 times larger than the magnetic field on the earth’s surface, characterized by its darker color or cave walls. Based on the mythical and historical review, the role of magnetic stones underlies the reason ancient people performed hermitage on rocks and in Mount Penanggungan. This study implies that it can be information for climbers that rocks with a strong magnetic field magnitude can accelerate the relaxation of the body. In addition, educators can integrate this research’s findings, including physical phenomena and historical/mythical aspects on Mount Penanggungan, into learning
Geomorphology and Geology Studies Using Digital Elevation Model (DEM) Data In the Watershed Area of Kampar Regency, Riau Province
Full text linkThis research was conducted in the area of Kampar Regency, Riau Province .it was located at coordinates including 01° 00' 40" - 00° 27' 00" South Latitude and 100° 28' 30"- 101° 14' 30" East Longitude. The purpose of this study was to determine the geological condition of the watershed, and it was determined the geomorphological condition of the watershed, to determine the number of divisions of the watershed, to determine the relationship between the watershed and rainfall, to determine the geological and geomorphological relationship with the watershed in the study area. The method used starts from field sampling, core description, distribution analysis of geological data, geomorphology, watershed analysis, and analysis of rainfall. Based on the analysis of the distribution of geological data in the research area, there were 12 geological formations from the results of geological mapping, namely: the Sihapas Formation, the Telisa Formation, the bekasap formation, the Bahorok Formation, the Farmer Formation, the Manggala formation, the Talang Akar formation, the Telisa Atas formation, the Palembang Tengah formation, Basement, members of the Lower Palembang formation (Air Berakat), members of the Upper Palembang formation (Muara Enim). In subsurface geology there were 8 well points in the study area, 2 correlations were carried out, namely the 1st correlation between CR-04, CR-03, CR-01, CR-02, CR-08, and the 2nd correlation between CR-05, CR-06, CR- 07. Geomorphological conditions were divided into 4 namely lowland areas, low hill areas, hilly areas, and high hill areas. The watersheds in the research area were divided into 2 watersheds, namely the Kampar and Siak watersheds. Watershed rainfall observations in the study area for 5 years from 2015 – 2019 were located at 5 different stations, with fluctuating rainfall intensit
The Effect of Sales Growth, Dividend Policy and Return on Assets on Debt Policy in Property and Real Estate Companies Listed on the Indonesia Stock Exchange in 2013 - 2017
Full text linkThe aim of this study was to examine and analyze the effect of Sales Growth, Dividend Policy and Return On Assets simultaneously and partially on Debt Policy in Property and Real Estate companies listed on the Indonesia Stock Exchange for the 2013–2017 period. The data analysis method used was multiple linear regression. The samples used in this study were 13 companies. The results of this study indicate that the variables Sales Growth, Dividend Policy and Return On Assets simultaneously have a significant effect on debt policy. Partially, Sales Growth and Dividend Policy have no significant effect on policy. Only Return On Assets has a significant effect on debt policy in property and real estate companies listed on the Indonesian stock exchange for the 2013-2017 perio
Morphological Analysis of Anak Krakatau Volcano after 22 December 2018 Eruption using Differential Interferometry Synthetic Aperture Radar (DInSAR)
Full text linkAnak Krakatau Volcano is an active volcano located in the Krakatau Complex, Sunda Strait, Indonesia. On 22 December 2018, the volcano experienced a major eruption that led to a tsunami that devastated the shores of the islands of Java and Sumatra and killed up to 437 people. The eruption also destroyed the volcano’s body and change its shape drastically and forming a large crater in the southwestern part. After that eruption, the volcano continues to grow up. This research aims to analyze the deformation of the Anak Krakatau Volcano post-2018 eruption by using the differential interferometry SAR method (DInSAR). In order to support the analysis, we additionally compare the DInSAR result with tectonic-volcanic activity. Sentinel 1-A type SLC satellite imagery data from 5 June 2019 to 7 January 2020; consisting of 19 images or 18 pairs as master and slave were used to producing a deformation map. DInSAR result shows the volcano was generally experiencing deflation during the period, ranging from -1.03 to -4.81 cm (-3.01 cm average). However, inflation also occurred ranging from 0 to 5.99 cm, correlating with shallow and deep volcanic activity and followed by eruptions in October 2019 when the highest activities were observed. Furthermore, coherence value should be highly considered along with DInSAR processing, and this research allows that coherence to be acceptable
Analysis of Petrophysical Parameter on Shaly Sand Reservoir by Comparing Conventional Method and Shaly Sand Method in Vulcan Subbasin, Northwest Australia
Full text linkVulcan Subbasin is an area with a lot of oil and gas exploration where is located in the Bonaparte Basin, Northwest Australia. There is some formation identified as sandstone reservoir with clay content which is usually called shaly sand based on the screening between resistivity log and density log. Clay content caused lower resistivity log readings so the shaly sand reservoir is considered as non-reservoir. To overcome this, a method besides the conventional method was applied to analyze the petrophysical parameters of shaly sand reservoir, it was shaly sand method. Petrophysical analysis is an analysis of rock physical parameters such as shale volume, porosity, and water saturation based on well log data. In this study, petrophysical analysis was carried out in the Vulcan Subbasin using 35 well log data, including gamma ray log, resistivity log, neutron log, and density log for the conventional method and shaly sand method involved Stieber equation and Thomas Stieber plot. The results obtained from this study are the comparison of petrophysical parameter values and pay summary between the conventional method and the shaly sand method, also its relation to the shale distribution type. By applying the shaly sand method, the average shale volume has decreased, the average porosity has increased, the average water saturation has increased, the average net to gross has increased, the average net thickness has increased, and the average net pay has increased. Changes in the average value were caused by laminated-dispersed shale distribution type which is influenced by diagenesis and the depositional environment of the formation
Sensitivity Analysis of Geomechanics Influence on The Success of Hydraulic Fracturing in Shale Gas Reservoir
Full text linkShale gas has a permeability of <0.1 mD and a porosity of around 2% - 8% to produce gas that rises to the surface through hydraulic fracturing and horizontal drilling. Geomechanics is one of the important factors that influence the success of a hydraulic fracturing job. Technology in fractures makes geomechanics a clear factor in predicting the success or failure of rocks in deformation and knowing the properties that will be faced by fracture fluids which will later be used to see the effectiveness of fracture fluids in resisting fractures. High operational costs need to be studied further to determine the parameters that affect hydraulic fracturing work, especially from the geomechanical aspect to minimize production failures and work safety. The research conducted this time focuses on the sensitivity of geomechanical parameters by using CMG (GEM) reservoir simulations for reservoir models and conducting Response Surface Methodology (RSM) in selection and ease when applied in the field prior to the hydraulic fracturing process. In this sensitivity study carried out on 5 parameters namely stress, Poisson's ratio, Young's modulus, biot coefficient, and pore pressure. The geomechanical parameter that has the most influence on hydraulic fracturing work based on the sensitivity results carried out through 500 data sets using the Analysis of Variance obtained R2 = 0.99 with the results based on the importance value of the pore pressure variable of 3.8. Then Young's modulus is 0.28, stress is 0.12, Poisson's ratio is 0.08, and biot coefficient is 0.04