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EAGE-HAGI 1st Asia Pacific Meeting on Near Surface Geoscience and Engineering
- Conference date: April 9-13, 2018
- Location: Yogyakarta, Indonesia
- Published: 09 April 2018
101 - 115 of 115 results
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The Feasibility of Resistivity Tunnel Monitoring System
Authors F. Syaifuddin, M. N. Puji, M. L. Zakaria, A. Mudhofar and H. AfifSummaryFrom the evaluation results of the modeling that has been done, the combination between the surface and borehole electrode configuration becomes the best solution to describe the subsurface condition. The lateral and vertical resolutions depend on the distance between the electrodes used, so that the utilization must be adjusted to the dimensions of the tunnel to be monitored. In general the method of monitoring tunnel conditions by using resistivity measurements is quite feasible and can still be developed for further purposes.
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Application Ground Penetrating Radar & Geomagnetic Method for Subsurface River-Crossing Oil Pipeline Detection
Authors A. Prihadi, P. Sumintadireja, F. Perdana, F.R. Aries, W.R. Lusano, K. Prabowo and SubarsyahSummaryOil pipeline is a national vital object that is used to transport oil from wellhead to onshore production facilities (OPF). It supports oil and gas industry operation throughout the country that in turn used distribute energy to its citizen. However, more than often, old facilities were designed and kept in paper format that could easily get damaged or lost. To exasperate the problem, actual construction of the pipeline could slightly deviate from the original blue print. Thus, exact location of the oil pipeline becomes uncertain. It becomes important to know the exact location when the operator want to construct new facilities without damaging the older facilities. The challenge in this investigation is to mapped a pipeline that crosses a river. The paper illustrate how geophysical method could be well utilized to accurately pin point man-made object beneath the surface and water.
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The investigation abandoned air-raid shelters by a high resolution S-wave refraction survey using ‘Land Streamer’
More LessSummaryIn order to found abandoned air-raid shelters in urban area, high resolution S-wave refraction survey was conducted. We used ‘Land Streamer’ because the condition of ground is paved in street.
Using ‘Land Streamer’ on paved ground allows to get seismic data which is little affected by static correction. In addition, acquired data is higher ratio signal to noise than using clay or tripod.
We processed the data and interpreted the profile. We picked up the potential points under where the abandoned shelters exist. As a result of drilling on the selected points, it was found that the abandoned shelters exist.
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Submarine mounds and implication to the exploration shallow reservoir in the Madura Strait, East Java Basin
By NurhasanSummaryThe study area is located in the Madura Strait, East Java basin with water depths ranging from 25 to 75 m. The objective of this study is to characterise seamounds inside the 3D seismic area, with respect to their implications to the shallow drilling hazards and also their application for exploration at the reservoir level. At least there are two types of seamound in this area: Type I is NY and MM seamound with dimensions length less than 1km, relief structure around 15m, seamound location conformal with the crest of the deeper reservoir structure and seamound masking the deeper image. Type II is ML seamound with dimensions length more than 1km, relief structure around 35m (double that of type I), seamound location is not conformal with the crest of the deeper reservoir structure and seamound is not masking the deeper image, it is confirmed that this type II seamound corresponds to coral reefs.
HR 2D seismic acquisition including analogue geophysical survey will result in better image of the seabed mound and sub seabed. Also advance processing seismic through PSDM needs to be done to get better image in the reservoir interval that was impaired below seamound.
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Optimizing Structural Trap with Stratigraphic Boundary Derived from Seismic Attribute.Case Study: Kais Reefal Carbonates
More LessSummaryArea of the study is in the bird head psc, with Kais carbonate which develop during miocene time. The structural trap cannot define the reservoir boundary itself, it is need the stratigraphical trap. The Stratigraphic trap derived from various attributes such as RMS amplitude, sweetness, isochrones map from Top Kais until pre Kais, and also acoustic impedance map. The boundary it will used for the volumetric calculation.
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Integration of Seismic attributes, Petrophysics & Rock physics for Depositional environment and facies characterization
Authors S.P. Muruthy and D. P. GhoshSummaryAn integrated reservoir characterization engages with the working of models illustrative of underground geological formations, which are then used to predict and optimize oil and gas production. It is obvious that no single discipline can give a full depiction of the reservoir characteristics. In order to create the most comprehensive reservoir understanding, an integrated reservoir model has turned out to be progressively important. The aim of this study is to evaluate the prediction of reservoir properties distribution and spatial distribution of facies by relating petrophysics and elastic properties of the rock to its depositional environment. The elastic properties of rock and the seismic attributes will indulge the propagation of facies and reservoir properties. The study will approach the challenge by integrating the well logs and seismic and the applied integration will be used for the conditional propagation of reservoir characterization. In accordance with that, this paper focuses on discriminating the fluid and the type of lithology to enhance the prediction of depositional environment of the prospect area.
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Interannual and decadal variations of summer temperature of the Kuroshio of the East China Sea from 1945 to 2010
By J. C. KangSummaryBased on the Ishii ocean climate database (1945 to 2010), the summer temperature were analyzed at the notable PN section of the Kuroshio in East China Sea (ECS) for the past 66 years, to discuss the inter-annual changes and variability of summer temperature with depth. The temperature values of average, largest and least are chosen, layer by layer with a 50m space, from the sea surface to 700m depth, to check out the inter-annual changes and variability. It can be found, that in the past 66 years, the temperature at the upper layers shallower than 300 m was significant warming, the warmer tendency was stronger at shallower layers; but the temperature tend to cold at the lower layers deeper than 500 m, the cooling tendency of the minimum values of temperature was more clearly and strong. The temperature difference between the upper layer and the lower layer was expanding during 1945 to 2010, this tendency become more obvious after year of 2000.
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Time-lapse CCR survey for a cost effective safety evaluation of river embankments
Authors C. Konishi, H. Saito, A. Shinsei, Y. Yamashita and T. KobayashiSummaryWe have conducted the time lapse CCR survey to evaluate the safety of the river embankment, and obtained good quality data for four measurements including an initial survey and three monitoring surveys after a certain amount of rainfall. Regardless of the amount of rainfall, the calculated resistivity change rate sections help us to detect the permeable zone that must be monitored intentionally to prevent the seepage failure of the river embankment. Although the resolution of the CCR survey is lower than the normal ERT result, the result is sufficient enough to detect the permeable zone. The detected permeable zone is coincided with the past damaged zone by heavy rainfall; thus the applicability of the method is validated. Since the cost and survey time can be significantly reduced from the usual ERT, the time lapse CCR is considered as a cost effective safety evaluation method of the river embankments.
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Quick Assessment of Padangsidimpuan’s Flash Flood, North Sumatera, Indonesia Using 2D Debris Flow Simulation SIMLAR v2.1
Authors I. Prinadiastari and P. BahriSummaryFlash flood hit Padangsidimpuan City, North Sumatera, Indonesia on March 26th, 2017, precisely in Batang Ayumi River. It shocked the citizen of Padangsidimpuan City because it never happened before within 34 years and caused five people died and many infrastructures failed. The flash flood was happened because of natural dam break which is triggered by heavy rainfall with long duration and change of land use on the upstream area. SIMLAR version 2.1 is a two dimensional debris flow simulation that integrated with GIS and resulted map of flood spread that informed the height and affected area of flood. The difference between the simulation result with field survey for the flood height is because the rough resolution of DEM and lack of actual discharge data as the main source of data for running the simulation. However, it can be concluded that if there is rain with high intensity and long duration on the upstream area of Batang Ayumi River, the flash flood is highly possible to occur again. Moreover, there is remaining material from flash flood that still lies on the river channel such as boulders and large tree trunks, while the downstream area is settlement with densely populated area.
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Effect of outside anomaly in the cross-hole electrical resistivity tomography
More LessSummaryCross-hole electrical resistivity tomography (CHERT) is very different from the Cross-hole travel time tomography since the measurement response is not only dependent on the properties between source and receiver. The anomalies outside the two boreholes will have unknown influence on the CHERT survey. In this study, the effects of outside anomaly were discussed from two aspects. First is the array cause that will lead to the symmetric effect in the inverted profile. The other is the extent of inversion region that will cause severely unexpected artifacts if not set up properly. This study aimed to use simple example to illustrate the correct application of CHERT method in engineering investigation. From the comparison of different electrode arrays and different inversion models, empirical countermeasures were proposed to obtain better CHERT results. The extended inversion model is recommended and the extended range on both side is suggested to be 1/2 of the borehole spacing. For the measurement configuration, at least two types of electrode arrays should be used in a CHERT survey, one without symmetric effect and the other with higher resolution. Hence, the combined data inversion or weight model stacking technique can be used to make better interpretation.
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Inorganic Fertilizer Residue Indication on Cinchona Plantation Soil Using Resistivity Method with Flat Base Electrodes
Authors D. N. Fawwaz, M. A. E. Rahadianto, D. Aulia, M. I. Putra, K. K. A. Brennaf and A. AfiatSummaryApplication of resistivity method on cinchona plantation at PTPN Bukit Tunggul VIII Lembang aims on understanding the pattern of soil layer and indication of exposed area of the inorganic fertilizer residue which has caused changes in physical characteristics, moreover the resistivity values of the soil. Research comes under the implementation of Wenner-Schlumberger with small spacing for better enhancement of near surface imaging. The usage of flat base electrode is also brought up to reduce the noise of small spacing, or in other words preventing bad datum points. By using geoelectric resistivity method, it has been proven that the fertilizer into the ground can be detected as an anomaly that has a lower resistivity value compared to the medium.
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Determination of Seepage Zones on Quartenary Volcanic Rock In Proposed Dams Using Geoelectric Resistivity In Indonesia
Authors A. Susilo and A. RachmansyahSummaryDipole-dipole and Schlumberger configuration are the nondestructive geophysical method sensitive to the conductive layer in the subsurface. These methods have been conducted to detect possible patterns of the dam seepage direction. The research was conducted in the area of Bajulmati Dam, Banyuwangi, Indonesia. The Schlumberger configuration was used to detect layers vertically (sounding), conducted in an outcrop in the area of inundation (axis-dam), and Dipole-Dipole configuration was conducted in 7 lines, close to the river line. The hypothesis is if the dam is inundated, it would not be full because there is a big spring in the South East area of this dam. The research aimed to answer whether there is a leakage in the South East area of dam. The result of Schlum-berger is used as the key to interpreting of the dipole-dipole measurements. The result indicated that the sedimentation model of Bajulmati dam area trend from the southwest to the northeast. Consequently if a leak/seepage happens, it will be the same direction as the trending sediment. This is different from the previous hypothesis, believing that the seepage would trend from northwest to southeast, which is supported by the presence of a fairly large spring trending to the southeast.
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The influence of near-surface hard rock environments on reverse time migration seismic imaging
Authors B. E. B. Nurhandoko, I. Sukmana and S. WidowatiSummaryImaging seismic waves beneath near surface hard rock have a complex challenge. The seismic waves will be scattered. Many seismic wave imaging targets, for example, hydrocarbon potentials, are under near surface hard rock environment such as: under reef or vulcanic rock.
Reflection seismic method, however, has some constraints to obtain good images beneath near surface hard rock environment. Irregularities of volcanic and carbonates rock create scattering and nonlinearity in the reflected wave. Then, the reflected wave propagates in caustics or non-linear paths. Therefore, many seismic migration methods fail in providing accurate image beneath near surface hard rock environment.
We present imaging cases beneath hard rock environment using reverse time migration based on inverse scattering. The migration uses individual shot record data and migrated by the reverse time migration of Born’s approximation. The inverse scattering reverse time integrates the whole individual migrated shot record data sequentially. The results show the layers and faults beneath hard rock environment can be revealed clearly. The longer far offset of split spread configuration produce better quality image than shorter far offset of one. The seismic imaging beneath near surface hard rock environment are useful for unlocking the new potential area beneath near surface hard rocks.
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Multi-Stage Exploration for SMSs using High-Resolution Seismic Systems
Authors K. Tara, E. Asakawa, F. Murakami, H. Tsukahara, S. Saito and M. KatoSummaryThe Multi-Stage Exploration is our proposed reflection seismic methods for SMS deposits. This investigation method consists of VCS (Vertical Cable Seismic) and ACS (Autonomous Cable Seismic) which we have proposed so far and ZVCS (Zero-offset Vertical Cable Seismic) which was first conducted in this research. ZVCS is a deep-tow exploration system using an upstanding cable. It is possible to easily separate and extract only a reflection wave from just below the ZVCS by vertically arranged hydro-phones.
In 2016, we carried out a Multi-Stage Exploration in the Izena Hole, which is one of the most promising hydrothermal sulfide ore deposits area around Japan. The purpose of this study is to understand the characteristic seismic facies of hydrothermal field and to show that the SMS deposit can be detected by this method.
The result of these high-resolution survey shows the follows: First, the lower boundary of the massive sulfide in the sedimentary layer can be identified by negative-polarity reflections. Second, a strong hydrothermal alteration zone can be identified as a low amplitude area. Third, massive sulfide deposits in hydrothermal activity area can be identified by velocity model and characteristic seismic facies.
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Exploring Shallow Gas in Indonesia as an Alternative to Increase National’s Gas Production
Authors R. Muammar, Z. Firdaus and D. RalanarkoSummaryBiogenic gas in Indonesia will become a good alternative to increase national’s gas production due to it is widely known that it is considered economic since it needs low production cost due to the shallow reservoir depth, combined with high C1 concentration. Since biogenic gas is commonly associated with drilling hazard, there is a large amount of biogenic gas deposit waiting to be explored, this, in turn, shows that biogenic gas is considered one of the best available alternative to ensure the national gas security.
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