New Perspectives on the Stratigraphy of the Andaman Trough, offshore North Sumatra, Indonesia. Utilising Modern Quantitative Biostratigraphical Analysis, Integrated with Newly Acquired 3D Multi Client Seismic Data

2021 ◽  
Author(s):  
N. Nirsal
Keyword(s):  
High Resolution ◽  
Deep Water ◽  
Seismic Data ◽  
Water Environment ◽  
Depositional Environments ◽  
Basin Formation ◽  
Well Data ◽  
Sequence Boundaries ◽  
Uplift And Erosion ◽  
North Sumatra

The Andaman Trough, located offshore North Sumatra is currently defined as an emerging basin for exploration. Its location primarily in a remote deep-water environment has resulted in limited well data being acquired to date and although there has historically been abundant seismic data, imaging of pre-Miocene stratigraphy has been poor. New seismic data, including the regional PGS NSMC3D and proprietary and multi-client 2D reprocessed data, combined with high resolution biostratigraphical analysis, has enabled extrapolation of the stratigraphy from the well explored and established shelfal areas down into the deep-water areas. To establish the high-resolution stratigraphic framework, paleo-environment, and paleo-climate for the well penetrations in the Andaman Trough, re-evaluation of quantitative and semi-quantitative abundance charts based on nannofossil, micropaleontology, and palynology zonation and sequences was conducted. Integration of this updated biostratigraphic analysis with interpretation from the modern regional seismic datasets enabled the identification of and confirmation of sequence boundaries and flooding surfaces across the Andaman Trough. Insights into timing of rifting, uplift, and erosion were made, as well as an interpretation of depositional environments, paleo-bathymetry and paleo-climate throughout the Andaman Trough. Significant findings include the chronostratigraphic separation of Late Oligocene Parapat fluvialtile deposits from the overlying Bampo marine turbidites, absent or incomplete Bampo Formation penetrated by some wells, as well as the delineation of a previously unidentified Eocene unconformity and revised timing of basin formation. Further insights into source rock development for the Eocene stratigraphic package were also developed.

scholarly journals Depositional Environment of Deep-Water Fan Facies: A Case Study of the Middle Miocene Interval at the Kutei and North Makassar Basins

2021 ◽  
Vol 22 (1) ◽  
pp. 45
Author(s):  
Kuntadi Nugrahanto ◽  
Ildrem Syafri ◽  
Budi Muljana
Keyword(s):  
Sea Level ◽  
Deep Water ◽  
Seismic Data ◽  
Depositional Environment ◽  
Middle Miocene ◽  
Oil And Gas ◽  
Seismic Stratigraphy ◽  
Horizontal Length ◽  
Sequence Boundaries

Massive exploration effort in the study area was conducted in 1996-2014 when deep-water drilling campaign found significant oil and gas discoveries but yet to optimally reach the middle Miocene deep-water sandstone reservoirs. Outcrops, well bores and 2D-seismic data had been incorporated in this study. Datum age from several taxon indicators have been utilized to correlate and unify various markers across the study area into four key biostratigraphy markers: M40, M45, M50, and M65. These four markers are at that point tied to the 2D seismic data in the act of the main horizons in conducting the seismic stratigraphy analysis over the study area not reached by wells. Identifying candidate of sub-regional sequence boundaries onshore and offshore that correspond with relative sea-level drops are the main result of this study. These results were integrated to generate the deep-water fan facies of the middle Miocene's gross depositional environment (GDE) maps, which generally show prograding succession easterly in the various shelf-breaks shifting laterally. The angle of slope and the horizontal length of the shelf-to-slope breaks significantly change from the Middle to Late Miocene until Recent time.Keywords: GDE, deep-water fan, Middle Miocene, Kutei, North Makassar.

Identification of Natural Gas Hydrates in Blocks 25a, 25b, 26 and 27 Offshore Trinidad Using Available Well Log Data

2014 ◽  
Author(s):  
M. M. Smith ◽  
L. E. Sobers
Keyword(s):  
Natural Gas ◽  
Deep Water ◽  
Gas Hydrates ◽  
Seismic Data ◽  
East Coast ◽  
Depositional Environments ◽  
Well Log ◽  
Borehole Data ◽  
Log Data ◽  
Natural Gas Hydrates

Abstract Natural gas hydrates can be found in conventional hydrocarbon depositional environments such as clastic marine sediments, siltstones and unconsolidated sands and in oceanic environments for reservoir pressures greater than 663 psi (46 bars) and temperatures less than 20 °C. These conditions are found in the deep water (> 300 m) acreage off the South East coast of Trinidad. Natural gas hydrates have been recovered in this area during drilling and seismic data have shown that there may be deposits in some areas. In this study we reviewed all the available borehole data and employed well log interpretation techniques to identify natural gas hydrates in the deep water acreage blocks 25 a, 25 b, 26 and 27 off the Trinidad South East coast. The analysis of well log data for the given depths did not present evidence to suggest the presence of natural gas hydrates in Blocks 25 a, 25 b, 26 and 27. In this paper we present our analysis of the data available and recommend the formation depths which should be logged in during the deep water exploration drilling to confirm the seismic data and core data which indicate the presence of natural gas hydrates in these blocks.

scholarly journals A 3D geological model of a structurally complex relationships of sedimentary Facies and Petrophysical Parameters for the late Miocene Mount Messenger Formation in the Kaimiro-Ngatoro field, Taranaki Basin, New Zealand

2021 ◽  
Author(s):  
Surya Tejasvi Thota ◽  
Md Aminul Islam ◽  
Mohamed Ragab Shalaby
Keyword(s):  
New Zealand ◽  
Deep Water ◽  
Water Environment ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Sequential Gaussian Simulation ◽  
Root Mean Square Amplitude ◽  
Petrophysical Parameters ◽  
Basin Floor ◽  
Complex Relationships

AbstractThe present study investigates the reservoir characteristics of the Mount Messenger Formation of Kaimiro-Ngatoro Field which was deposited in deep-water environment. A 3D seismic dataset, core data and well data from the Kaimiro-Ngatoro Field were utilized to identify lithofacies, sedimentary structures, stratigraphic units, depositional environments and to construct 3D geological models. Five different lithologies of sandstone, sandy siltstone, siltstone, claystone and mudstone are identified from core photographs, and also Bouma sequence divisions are also observed. Based on log character Mount Messenger Formation is divided into two stratigraphic units slope fans and basin floor fans; core analysis suggests that basin floor fans show better reservoir qualities compared to slope fan deposits. Seismic interpretation indicates 2 horizons and 11 faults, majority of faults have throw less than 10 m, and most of the faults have high angle dips of 70–80°. The Kaimiro and Ngatoro Fields are separated by a major Inglewood fault. Variance attribute helped to interpret faults, and other seismic attributes such as root-mean-square amplitude, envelope and generalized spectral decomposition also helped to detect hydrocarbons. The lithofacies model was constructed by using sequential simulation indicator algorithm, and the petrophysical models were constructed using sequential Gaussian simulation algorithm. The petrophysical parameters determined from the models comprised of  up to ≥ 25% porosity, permeability up to around 600mD, hydrocarbon saturation up to 60%, net to gross varies from 0 to 100%, majority of shale volumes are around 15–20%, the study interval mostly consists of macropores with some megapores and 4 hydraulic flow units. This study best characterizes the deep-water turbidite reservoir in New Zealand.

scholarly journals Reservoir Characterizarion Using Acoustic Impedance Inversion and Multi-Attribute Analysis in Nias Waters, North Sumatra

2019 ◽  
Vol 34 (1) ◽  
Author(s):  
Fathkhurozak Yunanda Rifai ◽  
Tumpal Bernhard Nainggolan ◽  
Henry Munandar Manik
Keyword(s):  
Seismic Data ◽  
Acoustic Impedance ◽  
Source Rocks ◽  
Time Migration ◽  
Attribute Analysis ◽  
Impedance Inversion ◽  
Acoustic Impedance Inversion ◽  
Well Data ◽  
North Sumatra ◽  
Rock Lithology

Seismic method is one of the most frequently applied geophysical methods in the process of oil and gas exploration. This research is conducted in Nias Waters, North Sumatra using one line 2D post-stack time migration seismic section and two wells data. Reservoir characterization is carried out to obtain physical parameters of rocks affected by fluid and rock lithology. Seismic inversion is used as a technique to create acoustic impedance distribution using seismic data as input and well data as control. As final product, multi-attribute analysis is applied to integrate of inversion results with seismic data to determine the lateral distribution of other parameters contained in well data. In this research, multi-attribute analysis is used to determine the distribution of NPHI as a validation of hydrocarbon source rocks. In that area, there is a gas hydrocarbon prospect in limestone lithology in depth around 1450 ms. Based on the results of sensitivity analysis, cross-plot between acoustic impedance and NPHI are sensitive in separating rock lithology, the target rock in the form of limestone has physical characteristics in the form of acoustic impedance values in the range of 20,000-49,000 ((ft/s)*(g/cc)) and NPHI values in the range of 5-35 %. While the results of the cross-plot between the acoustic impedance and resistivity are able to separate fluid-containing rocks with resistivity values in the range about 18-30 ohmm. The result of acoustic impedance inversion using the model based method shows the potential for hydrocarbons in the well FYR-1 with acoustic impedance in the range 21,469-22,881 ((ft/s)*(gr/cc)).

Ordovician glacial paleogeography: Integration of seismic spectral decomposition, well sedimentological data, and glacial modern analogs in the Murzuq Basin, Libya

2019 ◽  
Vol 7 (2) ◽  
pp. T383-T408 ◽  
Author(s):  
Francisco J. Bataller ◽  
Neil McDougall ◽  
Andrea Moscariello
Keyword(s):  
Seismic Data ◽  
Spectral Decomposition ◽  
Depositional Environments ◽  
Optimum Frequency ◽  
Data Set ◽  
Glacial Sediments ◽  
Depositional System ◽  
Significant Difference ◽  
Different Depths ◽  
Well Data

Ancient glacial sediments form major hydrocarbon plays in several parts of the world; most notably, North Africa, Latin America, and the Middle East. We have described a methodology for reconstructing broad-scale paleogeographies in just such a depositional system, using an extensive subsurface data set from the uppermost Ordovician glacial sediments of the Murzuq Basin of southwest Libya. Our workflow begins with the analysis of a large, high-quality 3D seismic data set, to understand the frequency content. Subsequently, optimum frequency bands are extracted, after applying spectral decomposition, and then recombined into an R (red) G (green) B (blue) blended cube. This volume is then treated as an image within which paleomorphological features can be distinguished and compared with modern glacial analogs. Mapping at different depths (time slices) of these features is then tied, by integration with core and image-log sedimentology, to specific depositional environments defined within the framework of a facies scheme developed using the well data and published outcrop studies. These depositional environments are extrapolated into areas with little or no well data using the spectral decomposition as a framework, always taking into account the significant difference in vertical resolution between the seismic data set and core-scale descriptions. The result of this methodology is a set of calibrated maps, at three different time depths (two-way time travel), indicating paleogeographic reconstructions of the glacial depositional environments in the study area and the evolution through time (at different depths/time slices 2D + 1) of these glacial settings.

scholarly journals Imaging of shallow structures around Küçükçekmece Lake in Istanbul land area with high resolution geophysical data.

2021 ◽  
Author(s):  
Hakan Alp ◽  
Okan Tezel ◽  
Denizhan Vardar ◽  
Yeliz İşcan Alp
Keyword(s):  
High Resolution ◽  
Cross Sections ◽  
Seismic Data ◽  
Active Faults ◽  
Structural Features ◽  
Shelf Area ◽  
Land Area ◽  
Seismic Section ◽  
Data Set ◽  
Well Data

Abstract Küçükçekmece Lake and surrounding land area play an important role to understand the active tectonism of the southern land area of Istanbul. This study gives the results of a geophysical survey to understand the structural features of the study area. We collected geo-electrical data on the surrounding Küçükçekmece Lake. Totally 14 different VES values were inverted and evaluated variation of resistivity with depth. Additionally, the obtained apparent resistivity cross-sections for 3 profiles of VES points. All of them are interpreted considering geological well data from the study area and previous geophysical studies, which included especially high resolution shallow seismic data and chirp seismic data from the lake and shelf area in the Sea of Marmara close to the lake. The resistivity sections and inverted VES data show that faults cut the recent units and also cause resistivity changes in these units in the land area. These faults are consistent with the orientation of active faults observed from the seismic section on the lake and deforming the lake floor. This data set can be given as geophysical evidence for the existence of faults in the Istanbul land area.

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