scholarly journals Carbonate oil and gas source rocks wettability alteration due to influence of polymer-colloidal drilling mud

2021 ◽  
pp. 17-27
Author(s):  
N. A. Skibitskaya ◽  
◽  
I. O. Burkhanova ◽  
M. N. Bolshakov ◽  
V. A. Kuzmin ◽  
...  
Keyword(s):  
Surface Properties ◽  
Oil And Gas ◽  
Pore Space ◽  
Space Structure ◽  
Source Rocks ◽  
Wettability Alteration ◽  
Drilling Mud ◽  
Rock Samples ◽  
Gas Saturation ◽  
Gas Source

Evaluation of rock wettability is an important task, since this parameter determines the distribution of water and oil in the reservoirs and their relative and phase permeability. The reliability of evaluation the wettability of rock samples depends on the drilling-in conditions during core sampling and core sample preparation methods. The investigation of the surface properties of the core from the Orenburg oil and gas condensate field showed that using of polymer-colloidal drilling mud leads to hydrophilization of the samples' surface. To obtain information on the actual wettability values of rock samples taken from wells drilled with polymer-colloidal drilling mud a method for estimating the relative (predominant) wettability of rocks based on petrophysical and lithological studies data is proposed. The authors suggest that the extraction of oil and gas source rock samples leads to irreversible changes in surface properties that cannot be restored. Keywords: selective wettability; relative wettability; predominant wettability; polymer-colloidal drilling mud; residual gas saturation; trapped gas saturation; pore space structure; extraction.

scholarly journals Influence of the pore space structure and wettability on residual gas saturation

Georesursy ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 2-7
Author(s):  
Rais S. Khisamov ◽  
Venera G. Bazarevskaya ◽  
Natalia A. Skibitskaya ◽  
Irina O. Burkhanova ◽  
Vladimir A. Kuzmin ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Pore Space ◽  
Space Structure ◽  
Gas Condensate ◽  
Angular Coefficient ◽  
Gas Saturation ◽  
Stage Of Development ◽  
Pore Space Structure ◽  
Residual Gas ◽  
Residual Gas Saturation

A significant part of hydrocarbon deposits in Russia is in the late stage of development. The distribution of residual oil and gas reserves is determined by the properties of the holding rocks. Estimating of deposits’ residual gas saturation is an important scientific task. The allocation of zones with the maximum undeveloped gas reserves will allow to select areas in long-developed fields for the intensification of production in the most efficient way. To search for such “sweet” zones, it is necessary to determine the factors that provide the value of the residual gas saturation. The reliance of the value of trapped in pores, residual gas saturation on such rock properties as pore space structure and wettability is studied in this article. The influence of formation pressure value and behaviour on making up of residual gas saturation during field development is not accounted in this work. The study of a wide collection of core sampled from productive deposits of the Orenburg oil and gas condensate field, the Vuktylskoe oil and gas condensate field, oil and gas field of Orenburg region, and also three areas in the East Caucasian petroleum province confirmed that the value of structure-trapped oil and gas saturation of carbonate and terrigenous rocks is directly proportional to the ratio of pore diameters and channels connecting them. Herewith the angular coefficient of the regression equation for this relationship for carbonate rocks directly depends on the quantitative characteristics of the predominant (relative) wettability. The obtained relationships make it possible to predict the value of residual gas saturation based on knowledge about the pore space structure and the surface properties of rocks.

THE PROBLEMS OF DETERMINING THE CONTENT OF KEROGEN IN THE OIL AND GAS SOURCE ROCKS

2019 ◽  
pp. 69-74
Author(s):  
N.I. Samokhvalov ◽  
◽  
K.V. Kovalenko ◽  
N.A. Skibitskaya ◽  
◽  
...  
Keyword(s):  
Oil And Gas ◽  
Source Rocks ◽  
Gas Source

scholarly journals Formation conditions and evolution of oil and gas source strata of the Laptev sea shelf ore and gas province

2021 ◽  
pp. 46-59
Author(s):  
V. Yu. Kerimov ◽  
Yu. V. Shcherbina ◽  
A. A. Ivanov
Keyword(s):  
Oil And Gas ◽  
Numerical Models ◽  
Sedimentary Basins ◽  
Water Area ◽  
Source Rocks ◽  
Gas Content ◽  
Laptev Sea ◽  
Hydrocarbon Generation ◽  
Gas Source ◽  
The Laptev Sea

Introduction. To date, no unified well-established concepts have been developed regarding the oil and gas geological zoning of the Laptev Sea shelf, as well as other seas of the Eastern Arctic. Different groups of researchers define this region either as an independently promising oil and gas region [7, 8], or as a potential oil and gas basin [1].Aim. To construct spatio-temporal digital models of sedimentary basins and hydrocarbon systems for the main horizons of oil and gas source rocks. A detailed analysis of information on oil and gas content, the gas chemical study of sediments, the characteristics of the component composition and thermal regime of the Laptev sea shelf water area raises the question on the conditions for the formation and evolution of oil and gas source strata within the studied promising oil and gas province. The conducted research made it possible to study the regional trends in oil and gas content, the features of the sedimentary cover formation and the development of hydrocarbon systems in the area under study.Materials and methods. The materials of production reports obtained for individual large objects in the water area were the source of initial information. The basin analysis was based on a model developed by Equinor specialists (Somme et al., 2018) [14—17], covering the time period from the Triassic to Paleogene inclusive and taking into account the plate-tectonic reconstructions. The resulting model included four main sedimentary complexes: pre-Aptian, Apt-Upper Cretaceous, Paleogene, and Neogene-Quaternary.Results. The calculation of numerical models was carried out in two versions with different types of kerogen from the oil and gas source strata corresponding to humic and sapropel organic matter. The results obtained indicated that the key factor controlling the development of hydrocarbon systems was the sinking rate of the basins and the thickness of formed overburden complexes, as well as the geothermal field of the Laptev Sea.Conclusion. The analysis of the results obtained allowed the most promising research objects to be identified. The main foci of hydrocarbon generation in the Paleogene and Neogene complexes and the areas of the most probable accumulation were determined. Significant hydrocarbon potential is expected in the Paleogene clinoforms of the Eastern Arctic.

scholarly journals Refinement of the petrophysical model of the Achimov formation based on facial analysis of sedimentation conditions

2021 ◽  
Vol 6 (4) ◽  
pp. 22-31
Author(s):  
Guzel R. Vahitova ◽  
Anzhela A. Kazaryan ◽  
Timur F. Khaybullin
Keyword(s):  
Oil And Gas ◽  
Facies Analysis ◽  
Pore Space ◽  
Sedimentary Cover ◽  
Clay Content ◽  
Geological Structure ◽  
Space Structure ◽  
Reservoir Properties ◽  
The Core ◽  
Promising Source

Aim. Due to the depletion of reserves of the main oil and gas complexes, the greatest interest is attributed to hard-to-recover reserves, complex-built objects of the sedimentary cover, the development of which was unprofitable until recently. One of these is the oil-bearing complex of the Achimov deposits of the Malobalykskoye field in Western Siberia. This article is devoted to the facies analysis and typification of reservoir rocks of the Achimov deposits in order to increase the reliability of determining the boundaries of the reservoirs, their interpretation and assessment of the petrophysical properties of the reservoirs. At the same time, special attention is paid to the facies analysis, which determines the characteristics of the reservoir. The Achimov deposits are a promising source of increasing resources and maintaining production at a high level. With their increasing importance, there are problems that complicate the search and assessment of deposits. Such problems include a high degree of reservoir compartmentalization, sharp facies variability, complex pore space structure, high clay content, low permeability values, etc. Materials and methods. The work is based on a comprehensive interpretation of the data of the lithological description of the core, the results of laboratory studies of the core and well logging data analysis of the Achimov deposits of the Malobalykskoye field. The methods used in the interpretation of GIS data, statistical analysis, comparison. Due to the fact that the reservoir properties of sand bodies are determined by the peculiarities of their formation in different conditions of sedimentation, it is necessary to establish a relationship between the petrophysical characteristics of rocks and their facies nature by substantiating petrofacies models. The use of the latter in geological modeling makes it possible to more effectively predict the reservoir properties (reservoir properties) of various facies lithotypes. Results. The paper presents the results of facies analysis and typification of the reservoirs of the Achimov deposits of the Malobalykskoye field, on the basis of which the boundaries of the reservoirs and the effective oilsaturated thicknesses were refined. Conclusions. Based on the results of the study, it can be concluded that it is necessary to develop refined petrophysical models for reservoirs with complex geological structure that take into account the facies features of rocks.

Geochemical characteristics of oil and gas source rocks of the southern part of the Pre-Ural foredeep

2021 ◽  
pp. 45-49
Author(s):  
A.S. Monakova ◽  
◽  
A.V. Osipov ◽  
V.I. Ermolkin ◽  
L.M. Bondareva ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Geochemical Characteristics ◽  
Source Rocks ◽  
Gas Source

scholarly journals Rendering Semisynthetic FIB-SEM Images of Rock Samples

2021 ◽  
Author(s):  
Ilia Safonov ◽  
Anton Kornilov ◽  
Iryna Reimers
Keyword(s):  
Focused Ion Beam ◽  
Oil And Gas ◽  
Rock Sample ◽  
Pore Space ◽  
Ion Beam ◽  
Ground Truth ◽  
Fine Tuning ◽  
Back Side ◽  
Sem Images ◽  
Rock Samples

Digital rock analysis is a prospective approach to estimate properties of oil and gas reservoirs. This concept implies constructing a 3D digital twin of a rock sample. Focused Ion Beam - Scanning Electron Microscope (FIB-SEM) allows to obtain a 3D image of a sample at nanoscale. One of the main specific features of FIB-SEM images in case of porous media is pore-back (or shine-through) effect. Since pores are transparent, their back side is visible in the current slice, whereas, in fact, it locates in the following ones. A precise segmentation of pores is a challenging problem. Absence of annotated ground truth complicates fine-tuning the algorithms for processing of FIB-SEM data and prevents successful application of machine- learning-based methods, which require a huge training set. Recently, several synthetic FIB- SEM images based on stochastic structures were created. However, those images strongly differ from images of real samples. We propose fast approaches to render semisynthetic FIB- SEM images, which imply that intensities of voxels of mineral matrix in a milling plane, as well as geometry of pore space, are borrowed from an image of rock sample saturated by epoxy. Intensities of voxels in pores depend on the distance from milling plane to the given voxel along a ray directed at an angle equal to the angle between FIB and SEM columns. The proposed method allows to create very realistic FIB-SEM images of rock samples with precise ground truth. Also, it opens the door for numerical estimation of plenty of algorithms for processing FIB-SEM data.

HYDROCARBON GENERATION IN THE AMADEUS BASIN, CENTRAL AUSTRALIA

1984 ◽  
Vol 24 (1) ◽  
pp. 42
Author(s):  
K. S. Jackson D. M. McKirdy ◽  
J. A. Deckelman
Keyword(s):  
Oil And Gas ◽  
Source Rocks ◽  
Hydrocarbon Generation ◽  
Liquid Hydrocarbons ◽  
Gas Source ◽  
Organic Facies ◽  
Hydrocarbon Fields ◽  
Central Australia ◽  
Oil Source ◽  
To Receive

The Proterozoic to Devonian Amadeus Basin of central Australia contains two hydrocarbon fields — oil and gas at Mereenie and gas at Palm Valley, both within Ordovician sandstone reservoirs. Significant gas and oil shows have also been recorded from Cambrian sandstones and carbonates in the eastern part of the basin. The hydrocarbon generation histories of documented source rocks, determined by Lopatin modelling, largely explain the distribution of the hydrocarbons. The best oil and gas source rocks occur in the Ordovician Horn Valley Siltstone. Source potential is also developed within the Late Proterozoic sequence, particularly the Gillen Member of the Bitter Springs Formation, and the Cambrian.Consideration of organic maturity, relative timing of hydrocarbon generation and trap formation, and oil/source typing leads to the conclusion that the Horn Valley Siltstone charged the Mereenie structure with gas and oil. At Palm Valley, only gas and minor condensate occur because the trap was formed too late to receive an oil charge. Differences in organic facies may also, in part, account for the dry gas and lack of substantial liquid hydrocarbons at Palm Valley. In the eastern Amadeus Basin, the Ordovician is largely absent but Proterozoic sources are well placed to provide the gas discovered by Ooraminna 1 and Dingo 1. Any oil charge here would have preceded trap development.

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