The multidisciplinary study of Gunung Padang has revealed compelling evidence of a complex and so... more The multidisciplinary study of Gunung Padang has revealed compelling evidence of a complex and sophisticated megalithic site. Correlations between rock stratifications observed through surface exposures, trenching and core logs, combined with GPR facies, ERT layers, and seismic tomograms, demonstrate the presence of multi‐layer constructions spanning approximately 20–30 m. Notably, a high‐resistive anomaly in electric resistivity tomography aligns with a low‐velocity anomaly detected in seismic tomography, indicating the existence of hidden cavities or chambers within the site. Additionally, drilling operations revealed significant water loss, further supporting the presence of underground spaces. Radiocarbon dating of organic soils from the structures uncovered multiple construction stages dating back thousands of years BCE, with the initial phase dating to the Palaeolithic era. These findings offer valuable insights into the construction history of Gunung Padang, shedding light on...
The Lombok earthquake in July 2018 caused considerable damage to public facilities and residentia... more The Lombok earthquake in July 2018 caused considerable damage to public facilities and residential areas. Most of the houses in the north of the island of Lombok were damaged by the 6.9 magnitude earthquake. We want to know what parameters cause houses and buildings in North Lombok not to experience a severe liquefaction process. We used near-surface tomographic resistivity imaging to characterize the subsurface of North Lombok to map the subsurface of the most affected areas in North Lombok. The geological condition of northern Lombok is the most vulnerable area to liquefaction due to volcanic loose sand layers, shallow groundwater, and thick deposits. However, almost all subsurface images from resistivity tomography from North Lombok show limestone layers at shallow depths, which may play an important role as a protective layer from liquefaction phenomena in this area.
IOP Conference Series: Earth and Environmental Science, 2021
The Lombok earthquake in 2018 was unique, the shocks occurred sequentially. Several major earthqu... more The Lombok earthquake in 2018 was unique, the shocks occurred sequentially. Several major earthquakes were followed by thousands of aftershocks. The earthquake caused a devastating disaster which destroyed many homes, buildings including wells as the main fresh water supply in the Lombok Island. The focal mechanism of main earthquake shows a thrust fault mechanism. Lombok Island is originally a volcano Island which is still growing actively. Therefore surface of Island is dominated by volcanic materials, such as: volcanic rock, volcanic ash, pumice. This paper describes the phenomenon of sanding wells in Lombok, including the physical mechanisms among rock’s grains when vibrating earthquake waves. These earthquake waves can eliminate static friction between grains and reduce cohesion between grains of rock. Some subsurface images shows a strong correlation between damage grade and the existence of loose sand and hard rock.
In recent years, coal as well as coal bed methane becomes important energy resources. Therefore, ... more In recent years, coal as well as coal bed methane becomes important energy resources. Therefore, the characterization of coal seam is also important in predicting the quality, porosity and pore’s fluid of CBM’s reservoir. Seismic wave is very important parameter to characterize reservoir’s properties of coal bed methane as well as quality of coal. In this paper, we show methodology to image the subsurface velocity using seismic tomography. It is very useful for characterizing the coal’s seam as well as to detect the position of intrusion body. A case study was carried out in Suban Block, Muara Enim Sumatera. This coal mining block contains igneous rock intrusion which becoming main control of coal’s quality. Coal which is close with intrusion body usually has better quality than far zone. To acquire the data, we used 48 channels of seismic recorder controlled by telemetry for controlling the shot and first break. Then, data are processed by Fresnel interpolated wave-path (FIW) wide-...
Porosity and mineral fraction information are crucial in reservoir characterization, however the ... more Porosity and mineral fraction information are crucial in reservoir characterization, however the exact value of these parameters is difficult to measure. We propose a new method for estimating the porosity and mineral fraction of carbonate rock from thin section images using an integrated neural network/image processing technique. Neural networks were built and trained to classify porosity and minerals of carbonate (calcite and dolomite) based on their color after chemical treatment. Pixel values of these colors were attributed with a target code value and represented in a 2D image (matrix) from which a simple image processing pixel filtering and counting algorithm was employed to calculate each fraction. Computation time was less than 40 seconds and classification error was less than 2%. This method may be useful as a cost-effective alternative for estimating 2D-porosity and mineral fraction for thin section images of rock. Unlike porosimetry or X-ray diffraction (XRD) measurements...
We present engineering airflow to intercept the transmission of Covid19 in public spaces and publ... more We present engineering airflow to intercept the transmission of Covid19 in public spaces and public transportations, which relatively fast and simple. This technique is to suppress effectively and as massive as possible the spread of aerosols and droplets contaminated with the COVID-19 virus that is flying in the air by providing a vertical downward flow using fans placed on the ceilings and the use of floors of the certain material so that aerosol and microdroplets will not bounce back up, difficult to roll, and firmly attached to the floor. The numerical airflow simulation shows that positioning the fan on the ceiling of the room will cause the air particle to move faster downward, which will push the microdroplets to fall to the floor more quickly, so that the microdroplets and aerosols will quickly move away from the most risk organs from the transmission, namely the mouth and nose. The contactangle test results on several floor materials always show a value of fewer than 90 deg...
The pore scales have impacts on transport mechanisms in shale gas reservoirs. In this research, d... more The pore scales have impacts on transport mechanisms in shale gas reservoirs. In this research, digital helium porosity meter is used for porosity measurement by considering real condition. Accordingly it is necessary to obtain a good approximation for gas filled porosity. Shale has the typical effective porosity that is changing as a function of time. Effective porosity values for three different shale rocks are analyzed by this proposed measurement. We develop the new measurement method for characterizing porosity phenomena in shale gas as a time function by measuring porosity in a range of minutes using digital helium porosity meter. The porosity of shale rock measured in this experiment are free gas and adsorbed gas porosoty. The pressure change in time shows that porosity of shale contains at least two type porosities: macro scale porosity (fracture porosity) and fine scale porosity (nano scale porosity). We present the estimation of effective porosity values by considering Boyle-Gay Lussaac approximation and Van der Waals approximation.
The early Miocene Baturaja Formation is one of the most prolific reservoirs in Tambun Field, West... more The early Miocene Baturaja Formation is one of the most prolific reservoirs in Tambun Field, West Java. The hydrocarbon mostly comes from the Upper Baturaja Formation reservoirs. These carbonate rocks show some complex porosity, lithology and facies. This study includes detail relationship among reservoir petrophysics , elastic wave parameters, effect of water saturation, pore type and facies of Baturaja carbonate rock to the seismic wave parameter, such as compressional and shear wave velocity. Many data were collected and studies carried out to obtain detailed relationships between seismic attributes and petrophysical parameters of the Baturaja carbonate, such as: petrographic analysis, SEM image, detail core description, well logging data analysis and laboratory experimental of seismic wave velocities measurements in variation of overburden pressure, pore pressure and temperature. Some seismic wave parameters were simulated as close as possible to the reservoirs condition. The result shows that the seismic wave velocity in the Baturaja carbonate has wide value range, i.e: compressional wave velocity (Vp) ranges from 3300 to 4000 m/s and shear-wave velocity (Vs) from 1500 to 2000 m/s. Based on petrophysical data and seismic wave measurement, the total porosity is not the only main factor controlling elastic wave parameters, as a matter of fact, the pore type plays also important role. A plot of porosity versus velocity displays an inverse trend encountered in the zone B and D, for zone A and C the diagram are slightly scatter. It is shown also that there is strong relationship between seismic wave velocity and lithology facies, therefore this result proves that seismic waves can be applied to facies determination in carbonates of Baturaja formation
... PHYSICS OF W ELL-LOG AND CORE Bagus Endar B. Nurhandoko1, Muhammad Thurisina Choliq2, Kaswand... more ... PHYSICS OF W ELL-LOG AND CORE Bagus Endar B. Nurhandoko1, Muhammad Thurisina Choliq2, Kaswandhi Triyoso2, Iwan Soemantri3, Sunu Hadi Praptono3, M ochamad Nurcahyo3 1) W ave Inversion and Subsurface Fluid ...
Extraordinary mudflow has happened in Sidoarjo, East Java, Indonesia since 2006. This mud comes f... more Extraordinary mudflow has happened in Sidoarjo, East Java, Indonesia since 2006. This mud comes from the giant crater that is located close to the BJP - 01. Thousands of homes have been submerged due to mudflow. Till today this giant mud crater is still has great strength despite the mud flowing over 8 years. This is a very rare phenomenon in the world. This mud flow mechanism raises big questions, because it has been going on for years, naturally the mudflow will stop by itself because the pressure should be reduced. This research evaluates all aspects of integrated observations, laboratory tests and field observations since the beginning of this ongoing mudflow. Laboratory tests were done by providing hot air bubbles into the fluid inside the inverted funnel showed that the fluid can flow with a high altitude. It is due to the mechanism of buoyant force from air bubbles to the water where the contrast density of the water and the air is quite large. Quantity of air bubbles provides direct effect to the ...
The subsurface temperature has many impacts on geological phenomena such as hydrocarbon generatio... more The subsurface temperature has many impacts on geological phenomena such as hydrocarbon generation, geothermal energy, mineralization, and geological hazards. The Northeast Java Basin has various interesting phenomena, such as many oil fields, active faults, mud eruptions, and some active and dormant volcanoes. We measured temperature data from tens of wells along a 130 km survey line with an average spacing of 5 km. We also measured the thermal conductivity of rocks of various lithologies along the survey line to provide geothermal heat flow data. We propose integrated modeling for profiling the subsurface temperature beneath the survey line from Mt. Lawu to Mt. Muriah in the Northeast Java Basin. The modeling of subsurface temperature integrates various input data such as a thermal conductivity model, surface temperature, gradient temperature, a geological model, and geothermal heat flow. The thermal conductivity model considers the subsurface geological model. The temperature mod...
Air merupakan salah satu sumberdaya alam yang sangat besar nilainya bagi semua mahluk hidup. Bagi... more Air merupakan salah satu sumberdaya alam yang sangat besar nilainya bagi semua mahluk hidup. Bagi kehidupan manusia, air merupakan salah satu kebutuhan dasar seperti minum, masak, mandi, mencuci, air juga dibutuhkan dalam proses industri. Pada umumnya pemenuhan kebutuhan air dilakukan dengan pemanfaatan air tanah. Air tanah lebih terlindung dari polusi atau pencemaran dan penyebarannya tidak merata di bawah permukaan. Telah dilakukan penelitian yang bertujuan untuk memetakan lapisan akuifer di Daerah Tanah Hitam Distrik Abepura. Daerah penelitian memiliki topografi yang tidak datar dan secara geologi termasuk dalam formasi Makats. Formasi tersebut tersusun oleh batulanau dan batulempung, sisipan napal dan konglomerat. Bagian bawah dari formasi ini jenis batuannya berupa tuf dan breksi gunungapi. Kegiatan penelitian bertujuan untuk memetakan sebaran akuifer menggunkan metode geolistrik tahanan jenis, konfigurasi Schlumberger. Berdasakan hasil pengukuran dan intepretasi data geolist...
Kondisi geologi di Zona Kendeng ini cukup kompleks dengan dominasi lapisan yang berumur tua dan s... more Kondisi geologi di Zona Kendeng ini cukup kompleks dengan dominasi lapisan yang berumur tua dan struktur sesar naik (thrust fault) yang intensif menyebabkan sulitnya memenuhi kebutuhan air bersih dari akuifer air tanah di daerah ini. Karakter akuifer di daerah ini berupa batuan napal karbonat formasi Kerek berumur Miosen.Analisis akuifer pada penelitian ini meliputi uji resistivity rock physics, pengukuran sudut kontak, dan pengukuran resistivitas tomografi di lapangan.Pengukuran resistivity rock physics menghasilkan nilai resistivitas batuan pada keadaan kering dan pada keadaan tersaturasi air tanah. Nilai resistivitas ini menjadi referensi untuk karakterisasi citra tomografi resistivitas. Sedangkan nilai sudut kontak menunjukkan apakah air akan merambat ke atas ataukan tertekan lebih dalam. Hasil pengukuran sudut kontak yang selalu bersudut kecil memperlihatkan bahwa sistem kapilaritas di akuifer napal karbonat formasi Kerek ini mendukung untuk menjadi akuifer yang baik. Air cen...
The subsurface temperature has many impacts on geological phenomena such as hydrocarbon generatio... more The subsurface temperature has many impacts on geological phenomena such as hydrocarbon generation , geothermal energy, mineralization, and geological hazards. The Northeast Java Basin has various interesting phenomena, such as many oil fields, active faults, mud eruptions, and some active and dormant volcanoes. We measured temperature data from tens of wells along a 130 km survey line with an average spacing of 5 km. We also measured the thermal conductivity of rocks of various lithologies along the survey line to provide geother-mal heat flow data. We propose integrated modeling for profiling the subsurface temperature beneath the survey line from Mt. Lawu to Mt. Muriah in the Northeast Java Basin. The modeling of subsurface temperature integrates various input data such as a thermal conductivity model, surface temperature, gradient temperature, a geological model, and geothermal heat flow. The thermal conductivity model considers the subsurface geological model. The temperature modeling uses the finite difference of Fourier's law, with an input subsurface thermal conductivity model, geothermal heat flow, and surface temperature. The subsurface temperature profile along with survey line shows some interesting anomalies which correlate with either subsurface volcanic activity or the impact of fault activity .
The multidisciplinary study of Gunung Padang has revealed compelling evidence of a complex and so... more The multidisciplinary study of Gunung Padang has revealed compelling evidence of a complex and sophisticated megalithic site. Correlations between rock stratifications observed through surface exposures, trenching and core logs, combined with GPR facies, ERT layers, and seismic tomograms, demonstrate the presence of multi‐layer constructions spanning approximately 20–30 m. Notably, a high‐resistive anomaly in electric resistivity tomography aligns with a low‐velocity anomaly detected in seismic tomography, indicating the existence of hidden cavities or chambers within the site. Additionally, drilling operations revealed significant water loss, further supporting the presence of underground spaces. Radiocarbon dating of organic soils from the structures uncovered multiple construction stages dating back thousands of years BCE, with the initial phase dating to the Palaeolithic era. These findings offer valuable insights into the construction history of Gunung Padang, shedding light on...
The Lombok earthquake in July 2018 caused considerable damage to public facilities and residentia... more The Lombok earthquake in July 2018 caused considerable damage to public facilities and residential areas. Most of the houses in the north of the island of Lombok were damaged by the 6.9 magnitude earthquake. We want to know what parameters cause houses and buildings in North Lombok not to experience a severe liquefaction process. We used near-surface tomographic resistivity imaging to characterize the subsurface of North Lombok to map the subsurface of the most affected areas in North Lombok. The geological condition of northern Lombok is the most vulnerable area to liquefaction due to volcanic loose sand layers, shallow groundwater, and thick deposits. However, almost all subsurface images from resistivity tomography from North Lombok show limestone layers at shallow depths, which may play an important role as a protective layer from liquefaction phenomena in this area.
IOP Conference Series: Earth and Environmental Science, 2021
The Lombok earthquake in 2018 was unique, the shocks occurred sequentially. Several major earthqu... more The Lombok earthquake in 2018 was unique, the shocks occurred sequentially. Several major earthquakes were followed by thousands of aftershocks. The earthquake caused a devastating disaster which destroyed many homes, buildings including wells as the main fresh water supply in the Lombok Island. The focal mechanism of main earthquake shows a thrust fault mechanism. Lombok Island is originally a volcano Island which is still growing actively. Therefore surface of Island is dominated by volcanic materials, such as: volcanic rock, volcanic ash, pumice. This paper describes the phenomenon of sanding wells in Lombok, including the physical mechanisms among rock’s grains when vibrating earthquake waves. These earthquake waves can eliminate static friction between grains and reduce cohesion between grains of rock. Some subsurface images shows a strong correlation between damage grade and the existence of loose sand and hard rock.
In recent years, coal as well as coal bed methane becomes important energy resources. Therefore, ... more In recent years, coal as well as coal bed methane becomes important energy resources. Therefore, the characterization of coal seam is also important in predicting the quality, porosity and pore’s fluid of CBM’s reservoir. Seismic wave is very important parameter to characterize reservoir’s properties of coal bed methane as well as quality of coal. In this paper, we show methodology to image the subsurface velocity using seismic tomography. It is very useful for characterizing the coal’s seam as well as to detect the position of intrusion body. A case study was carried out in Suban Block, Muara Enim Sumatera. This coal mining block contains igneous rock intrusion which becoming main control of coal’s quality. Coal which is close with intrusion body usually has better quality than far zone. To acquire the data, we used 48 channels of seismic recorder controlled by telemetry for controlling the shot and first break. Then, data are processed by Fresnel interpolated wave-path (FIW) wide-...
Porosity and mineral fraction information are crucial in reservoir characterization, however the ... more Porosity and mineral fraction information are crucial in reservoir characterization, however the exact value of these parameters is difficult to measure. We propose a new method for estimating the porosity and mineral fraction of carbonate rock from thin section images using an integrated neural network/image processing technique. Neural networks were built and trained to classify porosity and minerals of carbonate (calcite and dolomite) based on their color after chemical treatment. Pixel values of these colors were attributed with a target code value and represented in a 2D image (matrix) from which a simple image processing pixel filtering and counting algorithm was employed to calculate each fraction. Computation time was less than 40 seconds and classification error was less than 2%. This method may be useful as a cost-effective alternative for estimating 2D-porosity and mineral fraction for thin section images of rock. Unlike porosimetry or X-ray diffraction (XRD) measurements...
We present engineering airflow to intercept the transmission of Covid19 in public spaces and publ... more We present engineering airflow to intercept the transmission of Covid19 in public spaces and public transportations, which relatively fast and simple. This technique is to suppress effectively and as massive as possible the spread of aerosols and droplets contaminated with the COVID-19 virus that is flying in the air by providing a vertical downward flow using fans placed on the ceilings and the use of floors of the certain material so that aerosol and microdroplets will not bounce back up, difficult to roll, and firmly attached to the floor. The numerical airflow simulation shows that positioning the fan on the ceiling of the room will cause the air particle to move faster downward, which will push the microdroplets to fall to the floor more quickly, so that the microdroplets and aerosols will quickly move away from the most risk organs from the transmission, namely the mouth and nose. The contactangle test results on several floor materials always show a value of fewer than 90 deg...
The pore scales have impacts on transport mechanisms in shale gas reservoirs. In this research, d... more The pore scales have impacts on transport mechanisms in shale gas reservoirs. In this research, digital helium porosity meter is used for porosity measurement by considering real condition. Accordingly it is necessary to obtain a good approximation for gas filled porosity. Shale has the typical effective porosity that is changing as a function of time. Effective porosity values for three different shale rocks are analyzed by this proposed measurement. We develop the new measurement method for characterizing porosity phenomena in shale gas as a time function by measuring porosity in a range of minutes using digital helium porosity meter. The porosity of shale rock measured in this experiment are free gas and adsorbed gas porosoty. The pressure change in time shows that porosity of shale contains at least two type porosities: macro scale porosity (fracture porosity) and fine scale porosity (nano scale porosity). We present the estimation of effective porosity values by considering Boyle-Gay Lussaac approximation and Van der Waals approximation.
The early Miocene Baturaja Formation is one of the most prolific reservoirs in Tambun Field, West... more The early Miocene Baturaja Formation is one of the most prolific reservoirs in Tambun Field, West Java. The hydrocarbon mostly comes from the Upper Baturaja Formation reservoirs. These carbonate rocks show some complex porosity, lithology and facies. This study includes detail relationship among reservoir petrophysics , elastic wave parameters, effect of water saturation, pore type and facies of Baturaja carbonate rock to the seismic wave parameter, such as compressional and shear wave velocity. Many data were collected and studies carried out to obtain detailed relationships between seismic attributes and petrophysical parameters of the Baturaja carbonate, such as: petrographic analysis, SEM image, detail core description, well logging data analysis and laboratory experimental of seismic wave velocities measurements in variation of overburden pressure, pore pressure and temperature. Some seismic wave parameters were simulated as close as possible to the reservoirs condition. The result shows that the seismic wave velocity in the Baturaja carbonate has wide value range, i.e: compressional wave velocity (Vp) ranges from 3300 to 4000 m/s and shear-wave velocity (Vs) from 1500 to 2000 m/s. Based on petrophysical data and seismic wave measurement, the total porosity is not the only main factor controlling elastic wave parameters, as a matter of fact, the pore type plays also important role. A plot of porosity versus velocity displays an inverse trend encountered in the zone B and D, for zone A and C the diagram are slightly scatter. It is shown also that there is strong relationship between seismic wave velocity and lithology facies, therefore this result proves that seismic waves can be applied to facies determination in carbonates of Baturaja formation
... PHYSICS OF W ELL-LOG AND CORE Bagus Endar B. Nurhandoko1, Muhammad Thurisina Choliq2, Kaswand... more ... PHYSICS OF W ELL-LOG AND CORE Bagus Endar B. Nurhandoko1, Muhammad Thurisina Choliq2, Kaswandhi Triyoso2, Iwan Soemantri3, Sunu Hadi Praptono3, M ochamad Nurcahyo3 1) W ave Inversion and Subsurface Fluid ...
Extraordinary mudflow has happened in Sidoarjo, East Java, Indonesia since 2006. This mud comes f... more Extraordinary mudflow has happened in Sidoarjo, East Java, Indonesia since 2006. This mud comes from the giant crater that is located close to the BJP - 01. Thousands of homes have been submerged due to mudflow. Till today this giant mud crater is still has great strength despite the mud flowing over 8 years. This is a very rare phenomenon in the world. This mud flow mechanism raises big questions, because it has been going on for years, naturally the mudflow will stop by itself because the pressure should be reduced. This research evaluates all aspects of integrated observations, laboratory tests and field observations since the beginning of this ongoing mudflow. Laboratory tests were done by providing hot air bubbles into the fluid inside the inverted funnel showed that the fluid can flow with a high altitude. It is due to the mechanism of buoyant force from air bubbles to the water where the contrast density of the water and the air is quite large. Quantity of air bubbles provides direct effect to the ...
The subsurface temperature has many impacts on geological phenomena such as hydrocarbon generatio... more The subsurface temperature has many impacts on geological phenomena such as hydrocarbon generation, geothermal energy, mineralization, and geological hazards. The Northeast Java Basin has various interesting phenomena, such as many oil fields, active faults, mud eruptions, and some active and dormant volcanoes. We measured temperature data from tens of wells along a 130 km survey line with an average spacing of 5 km. We also measured the thermal conductivity of rocks of various lithologies along the survey line to provide geothermal heat flow data. We propose integrated modeling for profiling the subsurface temperature beneath the survey line from Mt. Lawu to Mt. Muriah in the Northeast Java Basin. The modeling of subsurface temperature integrates various input data such as a thermal conductivity model, surface temperature, gradient temperature, a geological model, and geothermal heat flow. The thermal conductivity model considers the subsurface geological model. The temperature mod...
Air merupakan salah satu sumberdaya alam yang sangat besar nilainya bagi semua mahluk hidup. Bagi... more Air merupakan salah satu sumberdaya alam yang sangat besar nilainya bagi semua mahluk hidup. Bagi kehidupan manusia, air merupakan salah satu kebutuhan dasar seperti minum, masak, mandi, mencuci, air juga dibutuhkan dalam proses industri. Pada umumnya pemenuhan kebutuhan air dilakukan dengan pemanfaatan air tanah. Air tanah lebih terlindung dari polusi atau pencemaran dan penyebarannya tidak merata di bawah permukaan. Telah dilakukan penelitian yang bertujuan untuk memetakan lapisan akuifer di Daerah Tanah Hitam Distrik Abepura. Daerah penelitian memiliki topografi yang tidak datar dan secara geologi termasuk dalam formasi Makats. Formasi tersebut tersusun oleh batulanau dan batulempung, sisipan napal dan konglomerat. Bagian bawah dari formasi ini jenis batuannya berupa tuf dan breksi gunungapi. Kegiatan penelitian bertujuan untuk memetakan sebaran akuifer menggunkan metode geolistrik tahanan jenis, konfigurasi Schlumberger. Berdasakan hasil pengukuran dan intepretasi data geolist...
Kondisi geologi di Zona Kendeng ini cukup kompleks dengan dominasi lapisan yang berumur tua dan s... more Kondisi geologi di Zona Kendeng ini cukup kompleks dengan dominasi lapisan yang berumur tua dan struktur sesar naik (thrust fault) yang intensif menyebabkan sulitnya memenuhi kebutuhan air bersih dari akuifer air tanah di daerah ini. Karakter akuifer di daerah ini berupa batuan napal karbonat formasi Kerek berumur Miosen.Analisis akuifer pada penelitian ini meliputi uji resistivity rock physics, pengukuran sudut kontak, dan pengukuran resistivitas tomografi di lapangan.Pengukuran resistivity rock physics menghasilkan nilai resistivitas batuan pada keadaan kering dan pada keadaan tersaturasi air tanah. Nilai resistivitas ini menjadi referensi untuk karakterisasi citra tomografi resistivitas. Sedangkan nilai sudut kontak menunjukkan apakah air akan merambat ke atas ataukan tertekan lebih dalam. Hasil pengukuran sudut kontak yang selalu bersudut kecil memperlihatkan bahwa sistem kapilaritas di akuifer napal karbonat formasi Kerek ini mendukung untuk menjadi akuifer yang baik. Air cen...
The subsurface temperature has many impacts on geological phenomena such as hydrocarbon generatio... more The subsurface temperature has many impacts on geological phenomena such as hydrocarbon generation , geothermal energy, mineralization, and geological hazards. The Northeast Java Basin has various interesting phenomena, such as many oil fields, active faults, mud eruptions, and some active and dormant volcanoes. We measured temperature data from tens of wells along a 130 km survey line with an average spacing of 5 km. We also measured the thermal conductivity of rocks of various lithologies along the survey line to provide geother-mal heat flow data. We propose integrated modeling for profiling the subsurface temperature beneath the survey line from Mt. Lawu to Mt. Muriah in the Northeast Java Basin. The modeling of subsurface temperature integrates various input data such as a thermal conductivity model, surface temperature, gradient temperature, a geological model, and geothermal heat flow. The thermal conductivity model considers the subsurface geological model. The temperature modeling uses the finite difference of Fourier's law, with an input subsurface thermal conductivity model, geothermal heat flow, and surface temperature. The subsurface temperature profile along with survey line shows some interesting anomalies which correlate with either subsurface volcanic activity or the impact of fault activity .
Pore pressure is pressure of fluids within the pores of a reservoir. Effective stress is equal to... more Pore pressure is pressure of fluids within the pores of a reservoir. Effective stress is equal to average of normal stress on surface grains when confining stress is applied to rock frame. Differential stress is difference between confining pressure and pore pressure. There are difference concept between effective stress and differential stress due to stiffness of rock. Seismic wave plays important role in detecting pore pressure indirectly. Shallow gas pocket, shallow water flows and over-pressured zones are a major hazard in deepwater drilling projects. Detection of pore pressure prior to drilling would save millions of dollars in lost drilling costs. In this paper, we present the effect of fluid pressure on velocities of seismic, especially in non-soft carbonate rock. Carbonate rock is interesting reservoir rock since more than 50% proven reservoir in the world is carbonate reservoir. The carbonate rock is usually non-soft rock, especially reef and clastics carbonate. However, the effects of pore pressure changes in carbonate reservoir are less understood, since the frame of carbonate is usually stiff instead of soft frame. Here, we focus on understanding the effects of fluid pressure on velocities in non-soft rock. The effect of pore pressure of various fluids in stiff pore of carbonate using laboratory measurement is presented. We present also theoretically the effect of gas pore pressure within stiff-pore on velocities of seismic which shows interesting anomaly.
Pore pressure is pressure of fluids within the pores of a reservoir. Effective stress is equal to... more Pore pressure is pressure of fluids within the pores of a reservoir. Effective stress is equal to average of normal stress on surface grains when confining stress is applied to rock frame. Differential stress is difference between confining pressure and pore pressure. There are difference concept between effective stress and differential stress due to stiffness of rock. Seismic wave plays important role in detecting pore pressure indirectly. Shallow gas pocket, shallow water flows and over-pressured zones are a major hazard in deepwater drilling projects. Detection of pore pressure prior to drilling would save millions of dollars in lost drilling costs. In this paper, we present the effect of fluid pressure on velocities of seismic, especially in non-soft carbonate rock. Carbonate rock is interesting reservoir rock since more than 50% proven reservoir in the world is carbonate reservoir. The carbonate rock is usually non-soft rock, especially reef and clastics carbonate. However, the effects of pore pressure changes in carbonate reservoir are less understood, since the frame of carbonate is usually stiff instead of soft frame. Here, we focus on understanding the effects of fluid pressure on velocities in non-soft rock. The effect of pore pressure of various fluids in stiff pore of carbonate using laboratory measurement is presented. We present also theoretically the effect of gas pore pressure within stiff-pore on velocities of seismic which shows interesting anomaly.
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