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.

scholarly journals Sedimentology and ichnology of Neogene Coastal Swamp deposits in the Niger Delta Basin, Nigeria

Geologos ◽  
2016 ◽  
Vol 22 (3) ◽  
pp. 191-200 ◽  
Author(s):  
Sunny C. Ezeh ◽  
Wilfred A. Mode ◽  
Berti M. Ozumba ◽  
Nura A. Yelwa
Keyword(s):  
Niger Delta ◽  
Depositional Environment ◽  
Gamma Ray ◽  
Depositional Environments ◽  
Well Log ◽  
Data Set ◽  
Depositional Settings ◽  
Niger Delta Basin ◽  
Core Descriptions ◽  
Tidal Processes

Abstract Often analyses of depositional environments from sparse data result in poor interpretation, especially in multipartite depositional settings such as the Niger Delta. For instance, differentiating channel sandstones, heteroliths and mudstones within proximal environments from those of distal facies is difficult if interpretations rely solely on well log signatures. Therefore, in order to achieve an effective and efficient interpretation of the depositional conditions of a given unit, integrated tools must be applied such as matching core descriptions with wireline log signature. In the present paper cores of three wells from the Coastal Swamp depositional belt of the Niger Delta are examined in order to achieve full understanding of the depositional environments. The well sections comprise cross-bedded sandstones, heteroliths (coastal and lower shoreface) and mudstones that were laid down in wave, river and tidal processes. Interpretations were made from each data set comprising gamma ray logs, described sedimentological cores showing sedimentary features and ichnological characteristics; these were integrated to define the depositional settings. Some portions from one of the well sections reveal a blocky gamma ray well log signature instead of a coarsening-upward trend that characterises a shoreface setting while in other wells the signatures for heteroliths at some sections are bell blocky in shaped rather than serrated. Besides, heteroliths and mudstones within the proximal facies and those of distal facies were difficult to distinguish solely on well log signatures. However, interpretation based on sedimentology and ichnology of cores from these facies was used to correct these inconsistencies. It follows that depositional environment interpretation (especially in multifarious depositional environments such as the Niger Delta) should ideally be made together with other raw data for accuracy and those based solely on well log signatures should be treated with caution.

scholarly journals Integration of sequence stratigraphy, rock physics and AI inversion to determine the prospective reservoir in the shelf environment of the Tarakan Basin, Indonesia

2021 ◽  
Vol 873 (1) ◽  
pp. 012037
Author(s):  
M Irsyad ◽  
B T Tampubolon ◽  
S Sukmono
Keyword(s):  
Sequence Stratigraphy ◽  
Depositional Environment ◽  
Gamma Ray ◽  
Rock Physics ◽  
High Resistivity ◽  
Log Data Analysis ◽  
Well Data ◽  
System Tracts ◽  
Inversion Analysis ◽  
Physic Analysis

Abstract The Tarakan Basin is one hydrocarbon basin in Indonesia with approximately 40 discoveries and more than 1000 MBOE reserves. This study discusses an approach to integrate the sequence stratigraphy, rock physics and acoustic impedance (AI) inversion analysis to determine the prospective reservoirs in the basin. PRG-1 well data is used in the sequence stratigraphy and rock physic analysis. The sequence stratigraphy analysis of PRG-1 shows that there are three system tracts: transgressive, low stand tract and high stand system tracts. The integration of sequence stratigraphy, rock physics and log data analysis show that the prospective reservoir interval in PRG-1 well is located at a depth of 4730-4780 feet. It is characterized by low gamma ray, low NPHI, low density and high resistivity. The prospective interval was deposited in early Pliocene as Tarakan Formation in the low stand system tract of shelf depositional environment. The AI map shows that the distribution of the prospective is around the PRG-1 and in the eastern part of the area.

scholarly journals Facies Analysis and Depositoinal Environment of D-3 Reservoir Sands Vin Field, Eastern Niger Delta

2019 ◽  
pp. 1-19
Author(s):  
Onyewuchi, Chinedu Vin ◽  
Minapuye, I. Odigi
Keyword(s):  
Seismic Data ◽  
Niger Delta ◽  
Depositional Environment ◽  
Gamma Ray ◽  
Facies Analysis ◽  
Depositional Environments ◽  
Width Ratio ◽  
Neutron Density ◽  
Wireline Logs ◽  
Isopach Map

Facies analysis and depositional environment identification of the Vin field was evaluated through the integration and comparison of results from wireline logs, core analysis, seismic data, ditch cutting samples and petrophysical parameters. Well log suites from 22 wells comprising gamma ray, resistivity, neutron, density, seismic data, and ditch cutting samples were obtained and analyzed. Prediction of depositional environment was made through the usage of wireline log shapes of facies combined with result from cores and ditch cuttings sample description. The aims of this study were to identify the facies and depositional environments of the D-3 reservoir sand in the Vin field. Two sets of correlations were made on the E-W trend to validate the reservoir top and base while the isopach map was used to establish the reservoir continuity. Facies analysis was carried out to identify the various depositional environments. The result showed that the reservoir is an elongate , four way dip closed roll over anticline associated with an E-W trending growth fault and contains two structural high separated by a saddle. The offshore bar unit is an elongate sand body with length: width ratio of >3:1 and is aligned parallel to the coast-line. Analysis of the gamma ray logs indicated that four log facies were recognized in all the wells used for the study. These include: Funnel-shaped (coarsening upward sequences), bell-shaped or fining upward sequences, the bow shape and irregular shape. Based on these categories of facies, the depositional environments were interpreted as deltaic distributaries, regressive barrier bars, reworked offshore bars and shallow marine. Analysis of the wireline logs and their core/ditch cuttings description has led to the conclusion that the reservoir sandstones of the Agbada Formation in the Vin field of the eastern Niger Delta is predominantly marine deltaic sequence, strongly influenced by clastic output from the Niger Delta. Deposition occurred in a variety of littoral and neritic environment ranging from barrier sand complex to fully marine outer shelf mudstones.

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 Interpretation and Reconstruction of Depositional Environment and Petroleum Source Rock Using Outcrop Gamma-ray Log Spectrometry From the Huai Hin Lat Formation, Thailand

2021 ◽  
Vol 9 ◽  
Author(s):  
Chawisa Phujareanchaiwon ◽  
Piyaphong Chenrai ◽  
Kasira Laitrakull
Keyword(s):  
Depositional Environment ◽  
Gamma Ray ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Turbidity Currents ◽  
Stratigraphic Framework ◽  
Facies Associations ◽  
Mineral Compositions ◽  
Gamma Ray Log ◽  
Low K

Gamma ray logs are most useful in identifying subsurface lithology and interpreting depositional environments. This study highlights the use of outcrop gamma-ray logs along with outcrop observations and total organic carbon (TOC) analysis to provide the stratigraphic framework of the organic-rich rocks of Huai Hin Lat Formation in central Thailand. The study reveals five sedimentary facies including (1) structureless sandstone, (2) structured sandstone, (3) interbedded sandstone and siltstone, (4) interbedded mudstone and siltstone and (5) calcareous mudstone. These facies can be grouped into two facies associations; mudstone-dominated and sandstone-dominated facies associations. The depositional environment was interpreted as lacustrine basin-fill subdivided into deep lacustrine environment and sublacustrine fan associated with the turbidity currents. The total gamma-log characteristics are closely related to the lithologies controlled primarily by clay mineral compositions. Whist, the use of spectral gamma-ray can reveal more details on depositional environments and conditions. In this study, U concentrations is proven to be useful in highlighting organic-rich rocks in low K and Th concentration successions due to its ability to be fixed in clay minerals and organic materials under an anoxic condition. Thus, the U spectral gamma ray is suggested to combine with conventional gamma ray log for depositional environment and recognition of organic-rich rocks.

Palaeoenvironment, sequence stratigraphy and palaeogeography of the Lower Cretaceous deposits of Mehdi Abad, Yazd Block, Central Iran

2020 ◽  
Vol 295 (1) ◽  
pp. 61-89
Author(s):  
Mohammad Safaei ◽  
Asadollah Mahboubi ◽  
Soroush Modabberi ◽  
Reza Moussavi-Harami
Keyword(s):  
Sequence Stratigraphy ◽  
Coastal Plain ◽  
Tidal Flat ◽  
Lower Cretaceous ◽  
Depositional Environment ◽  
Carbonate Platform ◽  
Depositional Environments ◽  
Sea Level Changes ◽  
Deep Basin

Four Lower Cretaceous sections in the southern Yazd Block were measured and studied to interpret the palaeoenvironments, synsedimentary tectonics, and sequence stratigraphy. The Early Cretaceous sedimentary record of this block, consisting of the Sangestan, Taft, Abkuh, and Darreh Zanjir formations, was mainly influenced by synsedimentary tectonic activities in a tectonically unstable basin. Field observations and laboratory studies were used to identify lithofacies and microfacies, based on which six depositional environments were identified: upper coastal plain (alluvial fans), shore, tidal flat, lagoon, shoal, and open marine. A carbonate-siliciclastic shallow platform including an alluvial-coastal plain and an inner platform is suggested for the depositional environment of the Sangestan Formation. The depth of the overall shallow sedimentary basin of Sangestan Formation increases from west to east and deposition was controlled by long- term sea-level changes. A carbonate platform consisting of inner and outer parts, including tidal flat, lagoon, open marine belts, is suggested for the depositional environment of the Taft and Abkuh formations, while the Darreh Zanjir Formation accumulated in a deep basin. The predominant facies demonstrate an overall transgression-regression cycle (the 2rd order cycle) during the depositional time of these formations in the southern Yazd Block.

scholarly journals Sequence Stratigraphy and Depositional Environment of the Zubair Formation in Rumaila Oilfields, Southern Iraq: Microfacies and Geochemistry

2021 ◽  
Vol 54 (2B) ◽  
pp. 28-41
Author(s):  
Hamid A. A. Alsultan
Keyword(s):  
Sea Level ◽  
Sequence Stratigraphy ◽  
Gamma Ray ◽  
Sediment Supply ◽  
Delta Front ◽  
Delta Plain ◽  
Quartz Arenite ◽  
Sandy Shale ◽  
Sonic Logs ◽  
Southern Iraq

In the Rumaila oilfields in southern Iraq, the Zubair Formation was deposited in a shallow environment as three main facies, delta plain, backshore, and delta front depositional conditions indicating a transition from delta front and delta plain to a highstand level due to the finning upward mode. The facies of the Zubair clasts show well-sorted quartz arenite sandstone, poorly sorted quartz arenite sandstone, clayey sandstone that has not been properly sorted, sandy shale, and shale lithofacies. The minor lithofacies were identified using well-logging methods (gamma ray, spontaneous potential and sonic logs) and petrography. The Zubair clasts are of transition environment that appears to be transported from freshwater and deposited in a marine environment forming many fourth-order cycles reflect sea level rise fluctuations and still-stand under tectonics developed the sequence stratigraphy. A misalignment between relative sea-level and sediment supply caused asymmetry sedimentary cycles. A shallower environment of shale-dominated rocks rich in organic matter and pyrite were exposed. The basinal shale of Ratawi at the Zubair bottom and the shallow carbonate of Shuaiba emplace on the Zubair represent the beginning of the delta build up (delta front and delta plain) to a highstand stage.

scholarly journals Sequence stratigraphy, quaternary basin analyses in the Adriatic Foredeep

2018 ◽  
Vol 34 (2) ◽  
pp. 635
Author(s):  
S. GURI ◽  
L. GJANI ◽  
S. RANXHA ◽  
M. GURl ◽  
A. XHAXHIU
Keyword(s):  
Sequence Stratigraphy ◽  
Depositional Environments ◽  
Tectonic Subsidence ◽  
Third Order ◽  
Depositional Sequences ◽  
Facies Distribution ◽  
Loose Deposits ◽  
System Tracts ◽  
Sea Coast

This paper intends to give the characterization of Quaternary loose deposits, near and along the sea coast zone, by evaluating lithological-geologic parameters, depositional environments and the tectonic subsidence. The main objectives are: - The lithologic-facial zone by mapping of lithologie composition and facies distribution. - The Quaternary basin analyses by interpreting depositional sequences of third order, where system tracts (lowstand, shelf wedge, transgressive and highstand) are individualized. - The present fluvial processes and delta configuration (Shkumbin, Seman).

scholarly journals LITHOLOGY INTERPRETATION BASED ON WELL LOG DATA ANALYSIS IN “JS” FIELD

2019 ◽  
Vol 1 (01) ◽  
pp. 31-37
Author(s):  
Tri Wulan Sari ◽  
Sujito Sujito
Keyword(s):  
Data Analysis ◽  
Depositional Environment ◽  
Gamma Ray ◽  
Well Log ◽  
Log Data ◽  
Neutron Porosity ◽  
Shaly Sand ◽  
Log Data Analysis ◽  
Well Data ◽  
Data Log

Reservoir lithology types in a prospect zone of hydrocarbon can be known through well log data analysis, both qualitatively and quantitatively. Lithology interpretation based on qualitatively well log data analysis, has been successfully carried out by K-1 and K-3 well log data on JS Field, West Natuna basin, Riau Islands.Main focus of the research is types of lithology indicated by response the petrophysical well data log of Lower-Middle Miocene Arang Formation. Arang Formation was deposited immediately on top Barat formation and depositional environment in this formation is transitional marine - marine. Petrophysics log shows well data are log gamma ray, resistivity, neutron porosity, density, and sonic. The limitation of study are on four types lithology, they are coal, sand, sally sand, and shale. Lithology on well K-1 dominate by shale, there is thin intersection between sand and coal. The well of K-1 have sand thickest around six meter. While on well K-3 Petrophysics log data shows thin intersection between coal, sand, shaly sand, and dominated by shale. The thickest Sand have thickness 29 meter, and thicker than on K-1 well. The result in this study, the formation dominated by types of lithology “shale”.

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