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"Penelitian ini akan membahas mengenai pemodelan penyebaran fasies sedimen laut dalam di salah satu lapangan yang mengandung gas di Cekungan Kutai. Fasies pengendapan di lapangan Y dibagi menjadi 5 yakni Channel Axis, Channel Margin, Levee Overbank, Mass Transport dan Mud. Fasies pengendapan tersebut dibedakan satu dengan yang lain dalam penelitian ini melalui perbedaan cut-off vshale dan pola log GR. Korelasi antar sumur menggunakan ketentuan stratigrafi sikuen dibantu dengan data plot gradien tekanan dan data seismik. Interpretasi data seismik 3D pada interval pemodelan yaitu interval A bertujuan untuk membentuk kerangka pemodelan penyebaran fasies. Pemodelan penyebaran fasies pada penelitian kali ini menggunakan metode Multi Point Statistic Simulation (MPS). Modul pemodelan MPS dalam software Petrel menyediakan sarana untuk menyertakan berbagai macam input data geologi dan geofisika dalam pemodelan fasies. Data input tersebut antara lain training image, seismik vshale dan data peta medan azimuth. Penelitian ini juga mencoba membandingkan proses pemodelan fasies menggunakan metode MPS dengan salah satu metode stochastic lainnya yakni SIS (Sequential Indicator Simulation). ......This study describes about fasies distribution modeling of deepwater deposit in one of gas field at Kutai Basin.The deepwater depositional fasies in Y field can be divided into 5 fasies such as Channel Axis, Channel Margin, Levee Overbank, Mass Transport and Mud. Vshale cut-off and GR log pattern are used for dividing one depositional fasies to other depositional facies. Sequence stratigraphy concept is applied on well to well correlation supported with other data like pressure gradien plot and seismic section. 3D seismic horizon interpretation at A interval aim to build model framework for fasies distribution. This research utilizes Multi Point Statistic Simulation (MPS) method to distribute the fasies. The MPS modeling modul in Petrel provides some options to use geology and geophysics data as modeling input. Thoose input data are training image, vshale seismic cube and azimuth field map. The study also tried to compare the facies modeling process using the MPS method with one of the other stochastic methods namely SIS ( Sequential Indicator Simulation )."

"Lokasi penelitian berada pada Formasi Cinambo wilayah Daerah Jatinunggal, Sumedang Jawa Barat. Pada lokasi ini, tersingkap dengan baik beberapa singkapan sepanjang Anak Sungai Ci Jaweu pada Desa Cibuyung dan Desa Cimanintin yang terbagi menjadi dua lintasan. Litologi penyusunnya adalah feldspathic wacke, allochemic mudstone, foraminiferal-packstone, foraminiferal-wackestone, dan batulanau. Porositas batuannya memiliki rentang poor – excellent (>25%). Berdasarkan pengamatan lapangan, pengukuran stratigrafi, dan analisis petrografi, lokasi penelitian tersusun atas Kelompok Fasies B, C, D, dan G yang terbagi lagi menjadi 7 anggota litofasies. Kelompok-kelompok fasies yang saling berasosiasi kemudian dikelompokan menjadi 3 asosiasi fasies yaitu Sandy-silt lobe distal, distal levee, dan distal silt-mud lobe. Analisis mikrofosil yang dilakukan, menunjukan lapisan pada lokasi penelitian memiliki umur Miosen Tengah/Miosen Akhir dan terendapkan pada lingkungan upper-lower bathyal. FormasiCinambo yang tersingkap pada daerah ini diinterpretasikan berada pada lingkungan kipas laut dalam bagian tengah (middle fan). ......The research location is in the Cinambo Formation in the Jatinunggal Region, Sumedang, West Java. At this location, several outcrops along the Ci Jaweu River in Cibuyung Village and Cimanintin Village are well exposed and are divided into two tracks. Its constituent lithologies are feldspathic wacke, allochemic mudstone, foraminiferal-packstone, foraminiferal-wackestone, and siltstone. The rock porosity ranges from poor to excellent (>25%). Based on field observations, stratigraphic measurements, and petrographic analysis, the study site is composed of Facies B, C, D, and G which are further divided into 7 lithofacies. Facies groups that are associated with each other are then grouped into 3 facies associations namely distal Sandy-silt lobe, distal levee, and distal silt-mud lobe. The microfossil analysis performed showed that the layers at the study site are Middle Miocene/Lower Miocene and were deposited in an upper-lower bathyal environment. The Cinambo Formation exposed in this area is interpreted to be in the middle fan environment."

""This volume offers a review of terrestrial geochemical sedimentology, integrate current research with earlier work. Understanding the origins of terrestrial geochemical sediments can provide insights into past environments, landform preservation and landscape erosion."--Jacket."

"Hujan merupakan salah satu faktor pemicu terjadinya longsor. Infiltrasi air hujan dapat mempengaruhi kestabilan hingga menyebabkan lereng longsor. Untuk itu perlu diketahui besar perubahan parameter tanah pada saat hujan hingga dapat menyebabkan lereng longsor.Dalam tulisan ini dilakukan penelitian melalui studi parametrik dengan menggunakan program Plaxis 2D berbasis metode elemen hingga. Kondisi awal lereng ditentukan dengan analisis balik menggunakan data sekunder, kemudian dibuat simulasi perubahan kondisi tanah pada lereng sebagai dampak dari hujan.Hasil penelitian menunjukkan bahwa peningkatan unit weight sekitar 11.5 %, naiknya muka air tanah, turunnya kohesi 1-5 kN/m2 serta turunnya sudut geser sekitar 1o dapat menurunkan stabilitas lereng hingga menyebabkan lereng longsor pada saat hujan. Selain itu ditinjau penggunaan tension crack pada pemodelan dengan Plaxis 2D.Hasil menunjukkan bahwa pembuatan interface sebagai bentuk tension crack pada Plaxis sama-sama memberikan penurunan SF yang sangat kecil sekali baik pada analisis drained maupun undrained dan hasil serupa juga didapat dari pemodelan tension crack bentuk celah pada kondisi drained. Untuk pemodelan tension crack bentuk celah pada kondisi undrained memberikan hasil yang lebih baik karena penurunan nilai SF lebih konsisten pada pemodelan yg berbeda dan terdapat penurunan nilai SF cukup besar jika dibandingkan dengan lereng tanpa tension crack.

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Rainfall is one of the triggers that can cause slope failure. Infiltration of rain water will influence the stability of the slope. Therefore, it is necessary to find the alteration of soil parameters that can cause the slope failure at rainy season.

In this paper, parametric study is conducted by using finite element software with plaxis 2D. Initial condition of the slope is determined with back analysis by using secondary data. Then, the alteration of soil is simulated as the effect of rainfall.

The result shows that the increase of unit weight about 11.5%, the increase of soil water surface, the decrease of cohesion about 1-5 kN/m2, and the decrease of friction angle around 1o, can reduce the slope stability and cause the failure at rainy season. Beside that, tension crack also was introduced on the slope model to observe the effect on Plaxis 2D modelling.

The result shows that the use of interface as tension crack in plaxis gives the same lower SF either for the drained or undrained analysis. The same result also shown in virtual crack model on drained analysis. For the use of virtual crack as tension crack for modelling in 2D analysis, virtual crack model shows better result because the decrease of SF is consistent among the models. There are also significant decrease of safety factor compared with model without tension crack.

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"Nenering Formation is essentially made up of semi-consolidated sediments, which are divided into basal conglomerate beds, conglomeratic sandstone, cross-bedded sandstone, and siltstone to muddy layers facies. It is overlie unconformable to the Berapit Formation, but conformable to the Kroh and Grik Formations. The stratigraphy of Nenering Formation is a fining upwards sequence where the thickness of conglomerate beds become thinner upwards and become thicker for conglomeratic sandstone. The thickness varies from 0.5 m to tenths of meters. The more sandy in the upper portion (cross-bedded sandstone) overlie with thin siltstone and mudstone facies. The clast and grain composition suggested that the material making up the sedimentary sequence were derived predominantly from the erosion of granitoid rocks and sedimentary and metamorphic rocks constitute a minor provenance. Imbrications and the trend sizes of clasts indicate that the palaeo-current flow toward northeast. Cross bedding that was found in conglomerate and sandstone indicates the main channel depositional environment. The sequence stratigraphy of this area match with the Saskatchewan fluvial braided channel model."