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Identifikasi Lapisan Akuifer Menggunakan Metode Seismik Refraksi di Desa Jatimulyo, Kecamatan Jati Agung, Kabupaten Lampung Selatan Rhahmi Adni Pesma; Mokhammad Puput Erlangga; Intan Adiani Putri; Risky Martin Antosia; Ruhul Firdaus; Gestin Mey Ekawati
Jurnal Geofisika Eksplorasi Vol 6, No 2 (2020)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v6i2.66

Abstract

An initial subsurface survey to predict the aquifer is important to avoid the unprospect drill location and getting groundwater with the right discharge. In this study, prediction of the aquifer was carried out using the seismic refraction method in Jatimulyo Village, Jati Agung District, South Lampung Regency. The data was collected on October 6, 2019 using the SUMMIT X One seismic tool with 24 Geophones. The first break data from p-wave travel time is processed and interpreted using the Hagiwara method. Interpretation results show that there are three layers of subsurface lithology in the study area. The weathering layer was found at 2 m to 3.5 m depth with average velocity of 360 m/s. The second layer is dry sand with a velocity of 890 m/s at a depth of 2 m to 8 m. The third layer with a 2300 m/s velocity is a mixture of clay rock and saturated sand at depths of more than 8 m. As a comparison there is resistivity distribution data on the same measurement line in the study area. The overall interpretation shows that at a depth of 12 m with saturated clay sedimentary rock as a prospect of aquifer in this study area.
INVESTIGASI AIR TANAH BERDASARKAN NILAI RESISTIVITAS DI DUSUN JATISARI, KABUPATEN LAMPUNG SELATAN Andri Yadi Paembonan; Purwaditya Nugraha; Nono Agus Santoso; Ruhul Firdaus; Gestin Mey Ekawati; Virgian Rahmanda; Felik Destian Putra Amijaya
Jurnal Geofisika Eksplorasi Vol 7, No 2 (2021)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v7i2.117

Abstract

Air tanah adalah sumber air tawar terbesar yang tersedia.  Air tanah ini sangat penting untuk kehidupan manusia maka dari itu perlu adanya identifikasi zona air tanah yang potensial sebagai salah satu solusi untuk krisis air bersih. Namun pada sebagian daerah sangat sulit untuk menemukan air tanah yang baik karena disebabkan oleh kondisi geologi yang kompleks. Penelitian ini bertujuan untuk mendapatkan informasi keberadaan air tanah dari variasi nilai resistivitas bawah permukaan dengan menggunakan metode Vertical Electrical Sounding (VES) di wilayah Dusun Jatisari, Desa Jatimulyo, Kecamatan Jati Agung, Lampung Selatan. Keberadaan air tanah umumnya memiliki nilai resistivitas rendah hingga sedang. Oleh karena itu, hasil dari penelitian ini akan sangat membantu masyarakat dalam mengetahui kedalaman zona jenuh air (akuifer) untuk mendapatkan air bersih. Dari hasil yang diperoleh terlihat bahwa air tanah dengan rentang nilai resistivitas 10 – 35 Ohm.m berada pada kedalaman yang berbeda-beda. Pada titik VES PKM_S1, PKM_S2, dan PKM_S3 lapisan akuifer berada pada kedalaman 7.5 m, sedangkan titik VES PKM_S4 berada pada kedalaman 36 m, dan titik VES PKM_S5 berada pada kedalaman 8.5 m.
OPTIMALISASI PROSES KOMPUTASI PELEBARAN PITA FREKUENSI DATA SEISMIK REFLEKSI BERBASIS INVERSI BERESOLUSI TINGGI UNTUK PENAFSIRAN STRATIGRAFI SEISMIK Ruhul Firdaus
Journal of Science and Applicative Technology Vol 2 No 1 (2018): Journal of Science and Applicative Technology June Chapter
Publisher : Lembaga Penelitian dan Pengabdian Masyarakat (LPPM), Institut Teknologi Sumatera, Lampung Selatan, Lampung, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (505.173 KB) | DOI: 10.35472/281468

Abstract

Resolution capability of seismic reflection data is becoming more interesting topic to discuss even for today. Several methods and approximations to attempt bandwidth extension of seismic reflection data have been proposed in wide variety. Among them is a non-stationary reflectivity inversion based on basis pursuit decomposition technique. The need of the method is increasing as it can provide realistic resolution of seismic data. The main advantages of the method are consistancy with log data, good lateral continuity, preserve amplitude and capable in denying artificial reflection feature. Nevertheless, its computational process is very expensive thus most pratitioners tend to avoid the method and look for another method that could serve quicker instead of better results.This paper attempt to propose a set of computational scheme which can be used flexibly for any prospective user to reduce the computational cost of the method.
Karakterisasi reservoir menggunakan metode Seismik Inversi Acoustic Impedance (AI) dan Seismik Multiatribut dengan Probabilistic Neural Network (PNN) pada lapangan Blok F3, North Sea Netherland Muhammad Intasya Falie Rizqi; Ruhul Firdaus
Journal of Science and Applicative Technology Vol 5 No 2 (2021): Journal of Science and Applicative Technology December Chapter
Publisher : Lembaga Penelitian dan Pengabdian Masyarakat (LPPM), Institut Teknologi Sumatera, Lampung Selatan, Lampung, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35472/jsat.v5i2.274

Abstract

A 3D seismic acquisition has been carried out for oil and gas exploration in F3 field block of North Sea sector of the Netherland formed between the Jurassic and Cretaceous periods. The presence of hydrocarbons is indicated by the phenomenon of bright spots and gas chimneys below the surface. The data used are 3D post stack time migration seismic data and four wells with well log, checkshot and marker data availability. This study uses two methods in determining reservoir zones, namely the acoustic impedance inversion method and the multi-attribute method with PNN. Both methods integrate seismic data with well data. AI inversion method is used to predict the physical properties of rocks, namely their acoustic impedance values. The multi-attribute method is used to predict well log properties from seismic data. Non-linear multi-attribute transformation is obtained by the process of training neural networks with a type of probabilistic neural network (PNN). In this research, acoustic impedance volume and porosity estimation volume will be made to identify the hydrocarbon reservoir prospect zone. The two methods are then applied to the Netherlands F3 seismic field data, and the results show that there are three sandstone reservoir zones that have an acoustic impedance range between 4100-4800 (m/s)*(gr/cc) and porosity range between 29-35 (% ).
ANALISIS KUANTITATIF SEISMIK INVERSI IMPEDANSI AKUSTIK DAN POROSITAS PADA ZONA TARGET LAPANGAN “IL” Indah Lestari; Gestin Mey Ekawati; Ruhul Firdaus
JGE (Jurnal Geofisika Eksplorasi) Vol 9, No 1 (2023)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v9i1.238

Abstract

Daerah penelitian ini terletak di Cekungan Bonaparte, Australia. Dalam memodelkan bawah permukaan dengan metode seismik inversi impedansi akustik, peneliti kebanyakan hanya menggunakan seismik inversi berbasis model based. Pada penelitian ini, penulis telah melakukan pemodelan impedansi akustik (IA) bawah permukaan dengan menggunakan metode seismik post-stack berbasis rekursif, model based, dan sparse spike. Penelitian ini bertujuan untuk mengetahui model impedansi akustik serta persebaran porositas dari hubungan log porositas dan impedansi akustik (IA) hasil inversi pada zona target daerah penelitian. Penelitian ini dilakukan menggunakan data seismik 3D post stack dan 4 data sumur yaitu MKS-1, MKS-2, MKS-3 dan MKS-4. Berdasarkan hasil pengolahan diperoleh bahwa persebaran impedansi akustik pada area target dengan seismik inversi berbasis rekursif, model based, dan sparse spike memiliki rentang IA sekitar 10000 ((ft/s)*(g/cc)) – 50000 ((ft/s)*(g/cc)) yang merupakan kisaran impedansi akustik untuk litologi sand berfluida – clean sand, serta memiliki persebaran porositas prediksi dari hasil seismik inversi memiliki rentang sekitar 0,037 – 0,176. Berdasarkan analisis kuantitatif terlihat bahwa seismik inversi sparse spike paling cocok dalam memodelkan parameter impedansi akustik dan porositas prediksi daerah penelitian dengan standar deviasi error sebesar 1867,167 untuk impedansi akustik prediksi dan 0,010 untuk porositas prediksi.