Sand Body Trend Delineation Decrypting from Stratigraphic Dip Pattern Analysis: Case Study within a Fluvio-Deltaic Setting, East Kalimantan, Indonesia

2021 ◽  
Author(s):  
Ivan Zhia Wu ◽  
Sarvagya Parashar ◽  
Banu Andhika ◽  
Susan Syahdina ◽  
Arrie Kurniawan ◽  
...  

Abstract During field development, a detailed understanding of reservoir geometry and associated sedimentary features within the sand sequence plays an important role in the effective recovery of hydrocarbon resources. Most aging fields encounter the common problem in well placement for effective production of the remaining hydrocarbon resources. The current example—onshore formation from Late Miocene in East Kalimantan—includes seismic data acquired during the 1970s and 1980s. Considering advancements and breakthroughs provided by current technology, the older information could provide a greater level of subsurface uncertainty. Geological challenges include comprehending geometry prediction and the continuity of the amalgamated distributary reservoir channels and the depositional architecture within a fluvio-deltaic environment in a structurally complex field. High-density borehole microresistivity image data from several wells in the study area were acquired to constrain and reduce the geological uncertainty resulting from poor control of subsurface imaging through the surface seismic data. Microresistivity imaging data were used to identify sedimentary features and to perform electrofacies analysis. The data are used for the structural reconstruction of sequences by decoding a different order of structural deformation and reconstructing the sediment transport direction at the time of deposition. The results are then incorporated within the regional geology context in the basin. The consistent shale/silt beddings in the studied wells indicate an overall structural dip trend of 10° toward the east. The structural deformation within the same section of these wells is identified by the characteristics in the rotation of the structural dips. This suggests the proximity of these wells in relation to the deformation plane of sub seismic features and helps refine the structural maps. During a later phase, the reservoir is correlated within the wells, and careful selection of a palaeocurrent indicator is established from the vertical distribution of the sedimentary beddings for paleogeography reconstruction. Based on this, the channel complex dispersal direction was observed to exhibit an overall easterly direction with complex migration, and the identified mouth bar sequences reveal more widespread geometry. The dispersion or variations observed in the studied wells are then correlated to the overall reservoir architecture within fluvio-deltaic settings. The case study demonstrates the applications of borehole microresistivity data and their importance in providing a high-resolution well-to-well correlation for sand body delineation within the targeted sequences. The results provide details about the structural complexity in the underlying subsurface litho-sequence and illustrate how behaviors change laterally from one well to another. This analysis helps develop a high-resolution geocellular model for the field.

2021 ◽  
Author(s):  
Rick Schrynemeeckers

Abstract Current offshore hydrocarbon detection methods employ vessels to collect cores along transects over structures defined by seismic imaging which are then analyzed by standard geochemical methods. Due to the cost of core collection, the sample density over these structures is often insufficient to map hydrocarbon accumulation boundaries. Traditional offshore geochemical methods cannot define reservoir sweet spots (i.e. areas of enhanced porosity, pressure, or net pay thickness) or measure light oil or gas condensate in the C7 – C15 carbon range. Thus, conventional geochemical methods are limited in their ability to help optimize offshore field development production. The capability to attach ultrasensitive geochemical modules to Ocean Bottom Seismic (OBS) nodes provides a new capability to the industry which allows these modules to be deployed in very dense grid patterns that provide extensive coverage both on structure and off structure. Thus, both high resolution seismic data and high-resolution hydrocarbon data can be captured simultaneously. Field trials were performed in offshore Ghana. The trial was not intended to duplicate normal field operations, but rather provide a pilot study to assess the viability of passive hydrocarbon modules to function properly in real world conditions in deep waters at elevated pressures. Water depth for the pilot survey ranged from 1500 – 1700 meters. Positive thermogenic signatures were detected in the Gabon samples. A baseline (i.e. non-thermogenic) signature was also detected. The results indicated the positive signatures were thermogenic and could easily be differentiated from baseline or non-thermogenic signatures. The ability to deploy geochemical modules with OBS nodes for reoccurring surveys in repetitive locations provides the ability to map the movement of hydrocarbons over time as well as discern depletion affects (i.e. time lapse geochemistry). The combined technologies will also be able to: Identify compartmentalization, maximize production and profitability by mapping reservoir sweet spots (i.e. areas of higher porosity, pressure, & hydrocarbon richness), rank prospects, reduce risk by identifying poor prospectivity areas, accurately map hydrocarbon charge in pre-salt sequences, augment seismic data in highly thrusted and faulted areas.


2021 ◽  
pp. 1-45
Author(s):  
Qin Su ◽  
Huahui Zeng ◽  
Yancan Tian ◽  
HaiLiang Li ◽  
Lei Lyu ◽  
...  

Seismic processing and interpretation techniques provide important tools for the oil and gas exploration of the Songliao Basin in eastern China, which is dominated by terrestrial facies. In the Songliao Basin, a large number of thin-sand reservoirs are widely distributed, which are the primary targets of potential oil and gas exploration and exploitation. An important job of the exploration in the Songliao Basin is to accurately describe the distribution of these thin-sand belts and the sand-body shapes. However, the thickness of these thin-sand reservoirs are generally below the resolution of the conventional seismic processing. Most of the reservoirs are thin-interbeds of sand and mudstones with strong vertical and lateral variations. This makes it difficult to accurately predict the vertical and horizontal distribution of the thin-sand bodies using the conventional seismic processing and interpretation methods. Additionally, these lithologic traps are difficult to identify due to the complex controlling factor and distribution characteristics, and strong concealment. These challenges motivate us to improve the seismic data quality to help delineate the thin-sand reservoirs. In this paper, we use the broadband, wide-azimuth, and high-density integrated seismic exploration technique to help delineate the thin-reservoirs. We first use field single-point excitation and single-point receiver acquisition to obtain seismic data with wide frequency-bands, wide-azimuth angles, and high folds, which contain rich geological information. Next, we perform the near-surface Q-compensation, viscoelastic prestack time migration, seismic attributes, and seismic waveform indication inversion on the new acquired seismic data. The 3D case study indicates the benefits of improving the imaging of thin-sand body and the accuracy of inversion and reservoir characterization using the method in this paper.


2013 ◽  
Vol 167 ◽  
pp. 72-83 ◽  
Author(s):  
J.S. L'Heureux ◽  
M. Long ◽  
M. Vanneste ◽  
G. Sauvin ◽  
L. Hansen ◽  
...  

1999 ◽  
Vol 158 (1-4) ◽  
pp. 89-109 ◽  
Author(s):  
T Marsset ◽  
B Tessier ◽  
J.-Y Reynaud ◽  
M De Batist ◽  
C Plagnol

2015 ◽  
Vol 19 (10) ◽  
pp. 4215-4228 ◽  
Author(s):  
P. Tokarczyk ◽  
J. P. Leitao ◽  
J. Rieckermann ◽  
K. Schindler ◽  
F. Blumensaat

Abstract. Modelling rainfall–runoff in urban areas is increasingly applied to support flood risk assessment, particularly against the background of a changing climate and an increasing urbanization. These models typically rely on high-quality data for rainfall and surface characteristics of the catchment area as model input. While recent research in urban drainage has been focusing on providing spatially detailed rainfall data, the technological advances in remote sensing that ease the acquisition of detailed land-use information are less prominently discussed within the community. The relevance of such methods increases as in many parts of the globe, accurate land-use information is generally lacking, because detailed image data are often unavailable. Modern unmanned aerial vehicles (UAVs) allow one to acquire high-resolution images on a local level at comparably lower cost, performing on-demand repetitive measurements and obtaining a degree of detail tailored for the purpose of the study. In this study, we investigate for the first time the possibility of deriving high-resolution imperviousness maps for urban areas from UAV imagery and of using this information as input for urban drainage models. To do so, an automatic processing pipeline with a modern classification method is proposed and evaluated in a state-of-the-art urban drainage modelling exercise. In a real-life case study (Lucerne, Switzerland), we compare imperviousness maps generated using a fixed-wing consumer micro-UAV and standard large-format aerial images acquired by the Swiss national mapping agency (swisstopo). After assessing their overall accuracy, we perform an end-to-end comparison, in which they are used as an input for an urban drainage model. Then, we evaluate the influence which different image data sources and their processing methods have on hydrological and hydraulic model performance. We analyse the surface runoff of the 307 individual subcatchments regarding relevant attributes, such as peak runoff and runoff volume. Finally, we evaluate the model's channel flow prediction performance through a cross-comparison with reference flow measured at the catchment outlet. We show that imperviousness maps generated from UAV images processed with modern classification methods achieve an accuracy comparable to standard, off-the-shelf aerial imagery. In the examined case study, we find that the different imperviousness maps only have a limited influence on predicted surface runoff and pipe flows, when traditional workflows are used. We expect that they will have a substantial influence when more detailed modelling approaches are employed to characterize land use and to predict surface runoff. We conclude that UAV imagery represents a valuable alternative data source for urban drainage model applications due to the possibility of flexibly acquiring up-to-date aerial images at a quality compared with off-the-shelf image products and a competitive price at the same time. We believe that in the future, urban drainage models representing a higher degree of spatial detail will fully benefit from the strengths of UAV imagery.


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