scholarly journals Application of GSTAR(1,1) model for layer peat soil predicted based on resistivity log data

2021 ◽  
Vol 2106 (1) ◽  
pp. 012031
Author(s):  
R Jonathan ◽  
Yundari ◽  
Nurhasanah ◽  
O Y E Nada

Abstract In this study, GSTAR modeling was carried out with the inverse of distance weight matrix obtained from Geoelectrical Resistivity data at several peatland locations around the Universitas Tanjungpura, Pontianak. This data can identify the subsurface layer of the soil through the electric current that binds into the soil. However, due to the limitation of the tool to measure the resistivity value, it can only measure 1/5 of the depth of the observation length. To overcome this problem, predictions are made at the next depth using the GSTAR model. The study began by measuring the resistivity value of the land using the geoelectric method and mapping it. Through this GSTAR modeling, predictions are made for the unobserved subsurface to determine the type of soil layer. Knowing the type of deeper soil layer can help contractors build plant concrete stakes to keep buildings safe on peatland. The results of the GSTAR(1.1) model are not accurate enough to estimate the resistivity value data. This is possible because the correlation between rock ages is not the same, so further analysis is required.

2015 ◽  
Vol 2015 ◽  
pp. 1-11
Author(s):  
A. Stanley Raj ◽  
D. Hudson Oliver ◽  
Y. Srinivas

Soft computing based geoelectrical data inversion differs from conventional computing in fixing the uncertainty problems. It is tractable, robust, efficient, and inexpensive. In this paper, fuzzy logic clustering methods are used in the inversion of geoelectrical resistivity data. In order to characterize the subsurface features of the earth one should rely on the true field oriented data validation. This paper supports the field data obtained from the published results and also plays a crucial role in making an interdisciplinary approach to solve complex problems. Three clustering algorithms of fuzzy logic, namely, fuzzyC-means clustering, fuzzyK-means clustering, and fuzzy subtractive clustering, were analyzed with the help of fuzzy inference system (FIS) training on synthetic data. Here in this approach, graphical user interface (GUI) was developed with the integration of three algorithms and the input data (AB/2 and apparent resistivity), while importing will process each algorithm and interpret the layer model parameters (true resistivity and depth). A complete overview on the three above said algorithms is presented in the text. It is understood from the results that fuzzy logic subtractive clustering algorithm gives more reliable results and shows efficacy of soft computing tools in the inversion of geoelectrical resistivity data.


2020 ◽  
Vol 21 (2) ◽  
pp. 123
Author(s):  
Bayu Buwana ◽  
Nurul Priyantari ◽  
Supriyadi Supriyadi

Faculty of Mathematics and Natural Sciences University of Jember located in Sumbersari District with lithological conditions in the form of volcanic rocks, lithosol soils, and regosol soils that are capable of absorbing water and potentially as aquifers. In point of fact, in the campus zona of the University of Jember including in the Faculty of Mathematics and Natural Sciences, there is always a shortage of freshwater for various academic and non-academic activities. Therefore, research needs to be conducted to assess the lithology of subsurface structures in the FMIPA zone so that the depth of groundwater layers and aquifer layers can be determined. The study was conducted using the Schlumberger array geoelectric resistivity method at 5 VES points. The results obtained in the form of resistivity log curves can be seen that at the five points VES has lithology in the form of clay, gravel, sandstone, and groundwater layer. Each VES point was identified the groundwater layer and some of them were identified as aquifers. The aquifer with the greatest thickness is found at point VES 2, which is to the west of the Baitul Ilmi Mosque, so it is recommended as the location of a new well.Keywords: lithology, aquifers, geoelectric resistivity method, groundwater.


1990 ◽  
Vol 30 (1) ◽  
pp. 310
Author(s):  
D. Lasserre

A large proportion of the North West Shelf development gas wells are long reach (greater than 3500 m) and highly deviated. For reservoir description and management purposes, comprehensive formation evaluation needs to be carried out in these wells.Considerable difficulties have been encountered with electric log data acquisition due to friction and borehole conditions in these long, highly-deviated wells. As a result, new techniques to log the zones of interest were introduced. A system using the drill pipe to transport the downhole logging tools has been successfully used.Also, low-toxicity oil-based mud (LTM) was introduced in order to ease drilling problems and borehole conditions. However, owing to the non-conductive nature of the oil-based drilling fluid, improvements were required in the vertical resolution of the resistivity measurements and the estimation of the formation porosity.A computer program using a forward deconvolution technique recently developed by Shell's research laboratory in Holland has been successfully applied to enhance the vertical resolution of the resistivity log reading.The large range of uncertainty on the pore volume has been reduced to reasonable level by calibrating the porosity log data against core data obtained in a well drilled with LTM.


2010 ◽  
Vol 183 (2) ◽  
pp. 543-556 ◽  
Author(s):  
Paul B. Wilkinson ◽  
Jonathan E. Chambers ◽  
Philip I. Meldrum ◽  
David A. Gunn ◽  
Richard D. Ogilvy ◽  
...  

EKSPLORIUM ◽  
2021 ◽  
Vol 42 (2) ◽  
pp. 119
Author(s):  
Dwi Haryanto ◽  
Yoshi Rachael ◽  
Dhatu Kamajati ◽  
Gagah Hari Prasetyo ◽  
Heri Syaeful ◽  
...  

ABSTRAK. Pemerintah Indonesia dalam Peraturan Presiden (Perpres) Nomor 38 Tahun 2018 tentang Rencana Induk Riset Nasional Tahun 2017–2045, menetapkan beberapa bidang utama yang akan menjadi prioritas penelitian nasional, salah satunya adalah bidang energi. Dalam tema riset teknologi kelistrikan berbasis energi baru dan terbarukan rendah/nol karbon terdapat topik riset teknologi Pembangkit Listrik Tenaga Nuklir (PLTN) skala komersial. Pada topik riset tersebut, ditetapkan bahwa dalam jangka waktu penelitian tahun 2020–2024, dihasilkan purwarupa PLTN. Pada penelitian ini, karakterisasi geoteknik tapak PLTN dilakukan dengan menggunakan metode seismik refraksi guna melengkapi data penelitian sebelumnya. Tujuan penelitian ini adalah untuk mengetahui profil perlapisan batuan bawah permukaan untuk estimasi pekerjaan terkait fondasi PLTN. Pemetaan geologi dan akuisisi data geofisika, pengolahan, serta interpretasi tanah/batuan berdasarkan parameter kecepatan gelombang kompresi (Vp). Hasil pemetaan geologi menunjukkan adanya 2 satuan batuan beku yaitu diorit kuarsa dan andesit. Hasil pengolahan dan interpretasi data seismik refraksi menghasilkan model penampang Vp pada lapisan batuan bawah permukaan. Terdapat 3 lapisan batuan di lokasi penelitian yaitu lapisan tanah (Vp = 361–715 m/s), lapisan batuan beku lapuk (Vp = 1.386–2.397 m/s), dan lapisan beku segar (Vp = 3.789–6.133 m/s). Perkiraan densitas batuan beku segar berdasarkan perhitungan adalah 2,43–2,74 g/cm3. Hasil pemodelan dapat menunjukkan kedalaman dan struktur bawah permukaan lapisan batuan beku segar yang dapat menjadi fondasi bangunan PLTN.ABSTRACT. Presidential Regulation (Perpres) number 38 of 2018 concerning the National Research Master Plan for 2017–2045, the Government of Indonesia establishes several main areas that will become national research priorities, one of which is the energy sector. In the research theme of electricity technology based on new and renewable low/zero carbon energy, there is the topic of research on commercial-scale Nuclear Power Plant (NPP) technology. On the research topic, it was determined that within the research period of 2020–2024, a prototype nuclear power plant would be produced. Research related to the geotechnical characterization of the nuclear power plant site using the seismic refraction method was carried out to complement the previous research data. The purpose of this study was to determine the subsurface rock layer profile for estimation of work related to nuclear power plant foundations. Geological mapping and geophysical data acquisition, processing, as well as soil/rock interpretation based on the compression wave velocity (Vp) parameter are carried out to achieve this goal. The results of geological mapping show that there are 2 igneous rock units, namely quartz diorite and andesite. The results of processing and interpreting seismic refraction data produced a cross-sectional model of Vp in the subsurface rock layers. There are 3 rock layers in the research location, namely soil layer (Vp = 361–715 m/s), weathered igneous rock layer (Vp = 1.386–2,396 m/s), and fresh igneous layer (Vp = 3.789–6.133 m/s). The estimated density of fresh igneous rock based on calculations is 2.43–2.74 g/cm3. The modeling results can show the depth and structure of the subsurface layer of fresh igneous rock that can be the foundation of nuclear power plants.


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