Depositional Environment & Sequence Stratigraphy of Eocene Reservoirs, Assam Shelf, India: A Multi Well Log Study

2010 ◽  
Author(s):  
Deepender Singh Bora ◽  
Neelimoy Baruah ◽  
Chandramani Shrivastva ◽  
Bianayananda Bharali
Keyword(s):  
Sequence Stratigraphy ◽  
Depositional Environment ◽  
Well Log

scholarly journals Stratigraphic architecture and depositional environment of the Paleocene-Lower Eocene aquifers system (Douala onshore basin, SW Cameroon)

2021 ◽  
Vol 11 (2) ◽  
pp. 549-560
Author(s):  
Serge Parfait Koah Na Lebogo ◽  
Dieudonnée Bisso ◽  
Jeannette Ngo Elogan Ntem ◽  
Joseph Mvondo Ondoa
Keyword(s):  
Sequence Stratigraphy ◽  
Depositional Environment ◽  
Gamma Ray ◽  
Clay Content ◽  
Depositional Environments ◽  
Well Log ◽  
Delta Front ◽  
Lower Eocene ◽  
System Tracts ◽  
System Tract

AbstractThe Paleocene-Lower Eocene N'kapa Formation has long been considered as an important groundwater and hydrocarbon resource in the eastern edge of the Douala Basin. The present study’s aim is to establish a possible link between the geological nature of this formation and the quality of potential aquifers using Gamma Ray well log, cuttings and outcrops through sedimentology and sequence stratigraphy studies. The results obtained from this study show that: lithofacies are dominated by clays, silts and sands/sandstones; gamma ray electrofacies are funnel-shaped to cylindrical-shaped with some bell-shaped; depositional environments are continental to shallow marine dominated by fluvial and sometimes tidal processes; fluvial channel-fill, tidal channel-fill and delta front bars sands are potential aquifers; sequence stratigraphy analysis reveals two transgressive–regressive cycles of second order (Danian to Selandian and Thanetian to Ypresian), two Highstand System Tracts, one Transgressive System Tract and one Lowstand System Tract; the high-resolution geometry of these sandy/sandstone sedimentary bodies shows that their distribution is linked to the hydrodynamic factors and the topography of the depositional environment. A total of two types of lithological facies of the reservoir levels were defined according to the volume of clay: clean sandstone (0–15%) and low clayey sandstone (15–30%). The gamma ray well log correlation shows that the thickness of the reservoir levels is variable and that the clay content (Vsh%) increases from the NE to the SW. As a result, the best potential aquifers appear to correspond to the fluvial channel-fill sands deposited during the base-level fall of Upper Paleocene age (Lower Thanetian).

scholarly journals Sikuen Stratigrafi Formasi Talang Akar Lapangan “Dr”, Sub–Cekungan Jambi,Cekungan Sumatera Selatan

2017 ◽  
Vol 14 (3) ◽  
pp. 263 ◽  
Author(s):  
Yusi Firmansyah ◽  
Dhehave Riaviandhi ◽  
Reza Muhammad Ganjar Gani
Keyword(s):  
Data Analysis ◽  
Sequence Stratigraphy ◽  
Depositional Environment ◽  
Well Log ◽  
Sediment Distribution ◽  
Meandering Channel ◽  
Delta Plain ◽  
Braided Channel ◽  
System Tracts ◽  
Crevasse Splay

The area of this study include to PT. Energi Mega Persada Tbk work area. The area of this study is located in Jambi Sub - Basin, South Sumatera Basin. This study is emphasized to examine the sequence stratigraphy of Talang Akar Formation. The data that is used in this study include core, mudlog, 3D seismic, well log, and palynomorf fossil. The result of those data analysis and data correlation are lithofacies, electrofacies, depositional environment, and stratigrahys sequences of Talang Akar Formation. From data analysis, the facies’ that develop in Talang Akar Formation are A, B, C, D, E, F, G, H, I, J, K, L, and M. Those facies’are deposited in fluvial – deltaicenvironment at Late Oligocene until Early Miocene. From the well correlation and seismic interpretation, the sediment distribution pattern of Talang Akar Formation become thicker and deeper in the west side and the highland is located relatively in the east of the study area. At the area of study Talang Akar formation is very influenced by structure. From the lithofacies and electrofacies analysis, there are six kinds of stratigraphy sequencesthat develop in the study area. System tracts LST-1 (braided channel) just developed at sequence-1. The other sequences developed TST 1 – 4 (floodplain meandering channel), TST 5 – 6 (marsh delta plain), HST 1 – 4 (crevasse splay meandering channel) and HST 5 – 6 (floodplain delta plain). .  Keywordsi: Sequence stratigraphy, facies,depositional environment, Talang Akar Formation, Jambi Sub - Basin. Daerah penelitian termasuk ke dalam wilayah kerja PT. Energi Mega Persada Tbk. Daerah penelitian berada di Sub – Cekungan Jambi, Cekungan Sumatera Selatan. Studi ini difokuskan untuk membahas sikuen stratigrafi Formasi Talang Akar. Dalam penelitian ini, data yang digunakan adalah core, mudlog, seismik 3 dimensi, well log, dan fosil palinomorf. Hasil dari analisis dan korelasi data tersebut adalah litofasies, elektrofasies, sikuen stratigrafi, dan lingkungan pengendapan dari Formasi Talang Akar. Dari analisis data tersebut didapatkan bahwa fasies yang berkembang pada Formasi Talang Akar adalah fasies A, B, C, D, E, F, G, H, I, J, K, L, dan M. Fasies tersebut diendapkan di lingkungan fluvial – deltaic pada umur Oligosen Akhir sampai Miosen Awal. Berdasarkan korelasi antar sumur dan interpretasi seismik, distribusi sedimen Formasi Talang Akar lebih menebal dan mendalam pada sisi barat dengan tinggian yang berada relatif pada bagian timur daerah penelitian. Pada daerah penelitian Formasi Talang Akar sangat dipengaruhi oleh struktur serta berdasarkan analisis litofasies dan elektrofasies terdapat 6 sikuen yang berkembang pada daerah penelitian. System tracts LST-1 (braided channel) hanya berkembang pada sikuen-1. Pada sikuen lainnya berkembang TST 1 – 4 (floodplain meandering channel), TST 5 – 6 (marsh delta plain), HST 1 – 4 (crevasse splay meandering channel) dan HST 5 – 6 (floodplain delta plain). Kata kunci : Sequence stratigraphy, facies, depositional environment, FormasiTalang Akar, Sub Cekungan Jambi.

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