scholarly journals Prediction of filtration and capacitive properties and oil saturation characteristics of complex structure carbonate reservoirs (on the example of the Northwestern part of DDB)

2020 ◽  
pp. 78-87
Author(s):  
O. V. Oliinyk ◽  
S. A. Vyzhva ◽  
V. V. Antoniuk ◽  
I. M. Bezrodna
Keyword(s):  
Gamma Ray ◽  
Complex Structure ◽  
Well Logging ◽  
Carbonate Reservoir ◽  
Donets Basin ◽  
Northwestern Part ◽  
Oil Saturation ◽  
Reservoir Rocks ◽  
Capacitive Properties ◽  
Carbonate Deposits

The world achievements of the study of carbonate reservoir rocks with secondary voids have been analyzed. An integrated approach to the study of this type of reservoir has been demonstrated on the example of reservoir rocks of the Visean strata of the South-Berestivske field in the North-Western part of the Dnipro-Donets Basin. The purpose of this article is to predict the reservoir filtration-capacitive properties, as well as oil saturation characte-ristics of complex carbonate reservoir rocks using well logging data. To solve this problem, an integrat-ed approach is used. It includes the methods of porosities balance and functional transformations (normalization) of the electrical and radioactive well logging curves (lateral logging - neutron gamma ray logging, impulse neu-tron-neutron logging - neutron gamma ray logging). As a result, the authors have identified intervals in the Visean carbonate deposits with cavernous voids and cracks. Each individual geophysical method is influenced by the structure of the void space. Due to this, when calculating the porosity coefficient for different probes, the au-thors identify intervals represented by carbonate deposits, mainly of the porous-cavernous type. However, there is an interval of 4287.6-4289.6 m of porous-cavernous-fractured type. It is established that in the selected layers the coefficients of different types of porosity are: secondary - 2.5-6%, cavernous - 1.7-5% and fracture -0.2%. The thickness of pro-ductive sediments varies within 0.8 - 2.4 m (the average value is 2 m). The authors also substantiated the choice of parameters when calculating the saturation coefficient in complex structural reservoirs. Moreover, it is noted that the reservoir properties are provided by the presence of secondary voids, namely the cavities through which the fluid is filtered, and the rock matrix is compacted, poor-porous and low-permeable.

Silurian carbonate reservoir rocks of the joint zone of the Khoreyver depression and the Chernyshev ridge

2021 ◽  
Vol 3 ◽  
pp. 41-48
Author(s):  
I.I. Danshchikova ◽  
◽  
T.V. Maidl ◽  
A.V. Zhuravlev ◽  
V.S. Nikiforova ◽  
...  
Keyword(s):  
Carbonate Reservoir ◽  
Void Space ◽  
Reservoir Rocks ◽  
Lower Silurian ◽  
Coastal Marine ◽  
First Case ◽  
Capacitive Properties ◽  
Chernyshev Ridge ◽  
Filtration Properties ◽  
Hydrocarbon Deposits

The paper presents a comprehensive study of low-capacity Silurian carbonate reservoir rocks in the northeastern regions of the Timan-Pechora province. Silurian deposits in the sections of the Khosedayu swell, the Talbey block, and the Makarikha-Salyukin anticlinal zone are mainly secondary dolomites and, to a lesser extent, limestones, as well as with low-power interlayers of agrillites, clay dolomites, dolomite-anhydrite rocks. The deposits were formed in coastal-marine and shallow-marine conditions. As a result of the conducted studies, it was noted that dolomites with a shadow biohermal structure have the best filtration properties in the Lower Silurian, and bioclastic limestones – in the Upper Silurian. The reservoir rocks of the Talbey block of the Chernyshev ridge have the best filtration-capacitive properties. The main volume of the void space in the first case is associated with cavities and cracks, in the second one – with matrix porosity. However, the signs of modern karst in the salts of Malo-Tavrotinsky strata observed from the core indicate a possible reformation of the deposits, which requires more careful attention when predicting deposits. The results obtained can contribute to the design of a rational system for the development of hydrocarbon deposits.

scholarly journals Cenomanian-Early Campanian Carbonate Reservoir Rocks of Northwestern Iraq: Diagenesis and Porosity Development

2018 ◽  
Vol 2 (2) ◽  
pp. 1-19
Author(s):  
Mohamed Al-Haj ◽  
Ali Al-Juboury ◽  
Aboosh Al-Hadidy ◽  
Dalia Hassan
Keyword(s):  
Upper Cretaceous ◽  
Gamma Ray ◽  
Carbonate Reservoir ◽  
Fractured Reservoir ◽  
Burial Diagenesis ◽  
Near Surface ◽  
Reservoir Rocks ◽  
Zone Ii ◽  
The Common ◽  
Highly Porous

The present work focuses on the upper Cretaceous (Cenomanian-early Campanian) carbonate successions in selected wells from northwestern Iraq. These successions are represented by Gir Bir (Cenomanian-early Turonian), Wajna (late Santonian) and Mushorah (early Campanian) Formations. The succession has affected by early burial near-surface, unconformity-related and deep burial diagenesis represented by cementation, neomorphism, dolomitization, dedolomitization, silicification, authigenesis of glauconite and pyrite, compaction, micritization, solution and porosity formation. The common porosity types are intergranular, fenestral, intercrystalline, moldic, vuggy, channel and fracture. Three porosity zones (I, II, and III) are identified depending on variation in gamma ray which reflects their shale content. The upper part of zone (II) is highly porous and regarded on the main reservoir unit in the middle and upper parts of the Gir Bir Formation. Fracture and moldic and vuggy dissolution features in addition to karstic and fissure features are responsible for the porosity increase in the fractured reservoir unit.

Evaluation of filtration-capacitive properties of complex reservoir rocks using the results of core microtomography

2019 ◽  
pp. 86-88
Author(s):  
S.R. Bembel ◽  
◽  
V.M. Aleksandrov ◽  
A.A. Ponomarev ◽  
P.V. Markov ◽  
...  
Keyword(s):  
Reservoir Rocks ◽  
Capacitive Properties

Late Permian carbonate concretions in the marine siliciclastic sediments of the Ravnefjeld Formation, East Greenland

2002 ◽  
pp. 126-132
Author(s):  
Jesper Kresten Nielsen ◽  
Nils-Martin Hanken
Keyword(s):  
Mineral Resources ◽  
Sedimentary Basins ◽  
Sedimentary Facies ◽  
Carbonate Reservoir ◽  
Upper Permian ◽  
Late Permian ◽  
East Greenland ◽  
Reservoir Rocks ◽  
Carbonate Concretions ◽  
Siliciclastic Sediments

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Kresten Nielsen, J., & Hanken, N.-M. (2002). Late Permian carbonate concretions in the marine siliciclastic sediments of the Ravnefjeld Formation, East Greenland. Geology of Greenland Survey Bulletin, 191, 126-132. https://doi.org/10.34194/ggub.v191.5140 _______________ This investigation of carbonate concretions from the Late Permian Ravnefjeld Formation in East Greenland forms part of the multi-disciplinary research project Resources of the sedimentary basins of North and East Greenland (TUPOLAR; Stemmerik et al. 1996, 1999). The TUPOLAR project focuses on investigations and evaluation of potential hydrocarbon and mineral resources of the Upper Permian – Mesozoic sedimentary basins. In this context, the Upper Permian Ravnefjeld Formation occupies a pivotal position because it contains local mineralisations and has source rock potential for hydrocarbons adjacent to potential carbonate reservoir rocks of the partly time-equivalent Wegener Halvø Formation (Harpøth et al. 1986; Surlyk et al. 1986; Stemmerik et al. 1998; Pedersen & Stendal 2000). A better understanding of the sedimentary facies and diagenesis of the Ravnefjeld Formation is therefore crucial for an evaluation of the economic potential of East Greenland.

Enhanced and Rock Typing-Based Reservoir Characterization of the Palaeocene Harash Carbonate Reservoir-Zelten Field-Sirte Basin-Libya

2021 ◽  
Author(s):  
Mohamed Masoud ◽  
W. Scott Meddaugh ◽  
Masoud Eljaroshi ◽  
Khaled Elghanduri
Keyword(s):  
Rock Type ◽  
Carbonate Reservoir ◽  
Classification Model ◽  
Reservoir Rocks ◽  
The Core ◽  
Core Samples ◽  
Rock Types ◽  
Rock Typing ◽  
Open Hole ◽  
Type Classification

Abstract The Harash Formation was previously known as the Ruaga A and is considered to be one of the most productive reservoirs in the Zelten field in terms of reservoir quality, areal extent, and hydrocarbon quantity. To date, nearly 70 wells were drilled targeting the Harash reservoir. A few wells initially naturally produced but most had to be stimulated which reflected the field drilling and development plan. The Harash reservoir rock typing identification was essential in understanding the reservoir geology implementation of reservoir development drilling program, the construction of representative reservoir models, hydrocarbons volumetric calculations, and historical pressure-production matching in the flow modelling processes. The objectives of this study are to predict the permeability at un-cored wells and unsampled locations, to classify the reservoir rocks into main rock typing, and to build robust reservoir properties models in which static petrophysical properties and fluid properties are assigned for identified rock type and assessed the existed vertical and lateral heterogeneity within the Palaeocene Harash carbonate reservoir. Initially, an objective-based workflow was developed by generating a training dataset from open hole logs and core samples which were conventionally and specially analyzed of six wells. The developed dataset was used to predict permeability at cored wells through a K-mod model that applies Neural Network Analysis (NNA) and Declustring (DC) algorithms to generate representative permeability and electro-facies. Equal statistical weights were given to log responses without analytical supervision taking into account the significant log response variations. The core data was grouped on petrophysical basis to compute pore throat size aiming at deriving and enlarging the interpretation process from the core to log domain using Indexation and Probabilities of Self-Organized Maps (IPSOM) classification model to develop a reliable representation of rock type classification at the well scale. Permeability and rock typing derived from the open-hole logs and core samples analysis are the main K-mod and IPSOM classification model outputs. The results were propagated to more than 70 un-cored wells. Rock typing techniques were also conducted to classify the Harash reservoir rocks in a consistent manner. Depositional rock typing using a stratigraphic modified Lorenz plot and electro-facies suggest three different rock types that are probably linked to three flow zones. The defined rock types are dominated by specifc reservoir parameters. Electro-facies enables subdivision of the formation into petrophysical groups in which properties were assigned to and were characterized by dynamic behavior and the rock-fluid interaction. Capillary pressure and relative permeability data proved the complexity in rock capillarity. Subsequently, Swc is really rock typing dependent. The use of a consistent representative petrophysical rock type classification led to a significant improvement of geological and flow models.

Sr Isotope Chemostratigraphy and Pb–Pb Age of the Riphean Carbonate Deposits of the Kharaulakh Uplift (Northeastern Margin of the Siberian Platform)

2021 ◽  
Vol 62 (03) ◽  
pp. 377-387
Author(s):  
B.B. Kochnev ◽  
A.B. Kuznetsov ◽  
D.R. Sitkina ◽  
A.Yu. Kramchaninov
Keyword(s):  
Siberian Platform ◽  
Sedimentary Cover ◽  
Complex Structure ◽  
The Arctic ◽  
86Sr Ratio ◽  
Sr Isotope ◽  
Upper Riphean ◽  
Carbonate Deposits

Abstract —The least altered limestones of the Ukta and Eselekh formations in the Precambrian section of the Kharaulakh uplift have a minimum 87Sr/86Sr ratio of 0.70673–0.70715. The lowest 87Sr/86Sr ratio of the overlying Neleger and Sietachan formations is 0.70791–0.70817. Based on these data, along with the earlier obtained positive δ13С values (up to 8‰) for the Kharaulakh section, we have estimated the age of the Ukta and Eselekh formations at 800–670 Ma and the age of the Neleger and Sietachan formations at ~640–580 Ma. The Pb–Pb isochron age of the least altered limestones of the Eselekh Formation calculated from eight samples is 720 ± 30 Ma. This age permits us to define the lower part of the Kharaulakh section of the Ukta and Eselekh formations to be the late Tonian of the International Chronostratigraphic Chart or to the Upper Riphean of the General Stratigraphic Scale of Russia. The presence of reliably dated Upper Riphean sediments in the Kharaulakh uplift indicates a more complex structure of the Precambrian sedimentary cover on the Arctic margin of the Siberian Platform than assumed earlier.

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