Assessing the lithological composition of carbonate rocks of the Permian age in order to clarify calculated parameters

2021 ◽  
pp. 60-74
Author(s):  
G. A. Smolyakov ◽  
N. V. Gilmanova ◽  
A. V. Sivkova
Keyword(s):  
Carbonate Rocks ◽  
Water Saturation ◽  
Komi Republic ◽  
Well Testing ◽  
Residual Water ◽  
Reservoir Properties ◽  
Oil Flow ◽  
Porosity And Permeability ◽  
Lithological Composition ◽  
Dissection Technique

The article deals with the determination of the reservoir properties of Permian-age carbonate rocks. There is a section dissection technique, taking into account the fossil organisms prevailing for a particular geological age. It was noted a high content of silica in the lower Artinskian deposits of Toravey and Varandey fields of the Komi Republic. The presence of silicon is associated with an increase in the population of siliceous sponges during this period of sedimentation; this fact caused the maximum values of porosity and permeability in the corresponding intervals. However, this was also the reason for the high values of the residual water saturation factor and, as a result, low oil flow rates from the lower Artinskian stage. The need for detailed correlation and accounting for the content of fossils in the rocks when dissecting the well section made it necessary to systematize the available actual material on core and well testing. It became obvious that the separation of reservoirs and stages at the qualitative level isn't possible, so quantitative estimates of the parameters that are significantly different for the upper and lower Artinskian deposits and allow you to dissect the well section were proposed.

scholarly journals Estimation of quantitative criteria of carbonate reservoirs of triassic deposits

2021 ◽  
Vol 3 (3) ◽  
pp. 87-100
Author(s):  
J. M. Tlepieva ◽  
N. S. Shilanov
Keyword(s):  
Middle Triassic ◽  
Carbonate Reservoirs ◽  
Hydrodynamic Characteristics ◽  
Residual Water ◽  
Laboratory Studies ◽  
Boundary Values ◽  
Complex Type ◽  
Reservoir Properties ◽  
Porosity And Permeability ◽  
Lithological Composition

This paper discusses the boundary values of the reservoir properties of carbonate rocks of the Triassic sediments of South Mangyshlak, which are important for the interpretation of production geophysical data and for perforating and blasting operations. In terms of lithological composition, Triassic deposits are represented by two types of commercial reservoirs terrigenous and carbonate. Carbonate reservoirs are localized in the volcanic-dolomite and volcanic-limestone strata of the Middle Triassic. These rocks are characterized by a complex type of reservoir: porous-fractured, porous-cavernous and fractured. Sediments of the Upper Triassic occur with erosion on the Middle Triassic sedimentary complex and are represented by alternating tuffaceous, silt-sandy and mudstone rocks. Polymictic sandstones are oil-saturated to varying degrees; oil deposits are confined to them. To substantiate the quantitative criteria of the reservoir, the results obtained during special laboratory studies of the core were used. Filtration studies were carried out, where physical and hydrodynamic characteristics were determined when oil was displaced by displacing reagents. The obtained parameters were used to construct correlations collector non-collector. Using the relationships between the reservoir properties of the reservoir, the dependence of the porosity and permeability on the residual water content, as well as open porosity and permeability on the dynamic porosity, the boundary values were determined.

scholarly journals An Integrated Microfacies and Well Logs-Based Reservoir Characterization of Yamama Formation, Southern Iraq

2021 ◽  
pp. 3570-3586
Author(s):  
Mohanad M. Al-Ghuribawi ◽  
Rasha F. Faisal
Keyword(s):  
Reservoir Characterization ◽  
Water Saturation ◽  
Effective Porosity ◽  
Well Logs ◽  
Petrophysical Properties ◽  
Reservoir Properties ◽  
Thin Sections ◽  
Porosity And Permeability ◽  
South Of Iraq ◽  
Southern Iraq

     The Yamama Formation includes important carbonates reservoir that belongs to the Lower Cretaceous sequence in Southern Iraq. This study covers two oil fields (Sindbad and Siba) that are distributed Southeastern Basrah Governorate, South of Iraq. Yamama reservoir units were determined based on the study of cores, well logs, and petrographic examination of thin sections that required a detailed integration of geological data and petrophysical properties. These parameters were integrated in order to divide the Yamama Formation into six reservoir units (YA0, YA1, YA2, YB1, YB2 and YC), located between five cap rock units. The best facies association and petrophysical properties were found in the shoal environment, where the most common porosity types were the primary (interparticle) and secondary (moldic and vugs) . The main diagenetic process that occurred in YA0, YA2, and YB1 is cementation, which led to the filling of pore spaces by cement and subsequently decreased the reservoir quality (porosity and permeability). Based on the results of the final digital  computer interpretation and processing (CPI) performed by using the Techlog software, the units YA1 and YB2 have the best reservoir properties. The unit YB2 is characterized by a good effective porosity average, low water saturation, good permeability, and large thickness that distinguish it from other reservoir units.

scholarly journals Petrophysical Properties of Nahr Umar Formation in Nasiriya Oil Field

2020 ◽  
Vol 21 (3) ◽  
pp. 9-18
Author(s):  
Ahmed Abdulwahhab Suhail ◽  
Mohammed H. Hafiz ◽  
Fadhil S. Kadhim
Keyword(s):  
Gamma Ray ◽  
Water Saturation ◽  
Oil Field ◽  
Well Logs ◽  
High Porosity ◽  
Reservoir Properties ◽  
Petrophysical Parameters ◽  
Resistivity Logs ◽  
Lithology Prediction ◽  
Porosity And Permeability

   Petrophysical characterization is the most important stage in reservoir management. The main purpose of this study is to evaluate reservoir properties and lithological identification of Nahr Umar Formation in Nasiriya oil field. The available well logs are (sonic, density, neutron, gamma-ray, SP, and resistivity logs). The petrophysical parameters such as the volume of clay, porosity, permeability, water saturation, were computed and interpreted using IP4.4 software. The lithology prediction of Nahr Umar formation was carried out by sonic -density cross plot technique. Nahr Umar Formation was divided into five units based on well logs interpretation and petrophysical Analysis: Nu-1 to Nu-5. The formation lithology is mainly composed of sandstone interlaminated with shale according to the interpretation of density, sonic, and gamma-ray logs. Interpretation of formation lithology and petrophysical parameters shows that Nu-1 is characterized by low shale content with high porosity and low water saturation whereas Nu-2 and Nu-4 consist mainly of high laminated shale with low porosity and permeability. Nu-3 is high porosity and water saturation and Nu-5 consists mainly of limestone layer that represents the water zone.

scholarly journals RESULTS OF PETROPHYSICAL STUDIES OF THE PRODUCTIVE STRATUM DEPOSITS OF THE BAKU ARCHIPELAGO NORTHERN OIL AND GAS BEARING AREAS

2020 ◽  
pp. 22-27
Author(s):  
V. Sultanov ◽  
L. Sultanov
Keyword(s):  
Granulometric Composition ◽  
Oil And Gas ◽  
Physical Parameters ◽  
Reservoir Properties ◽  
Secondary Porosity ◽  
North West ◽  
Productive Stratum ◽  
Porosity And Permeability ◽  
The Individual ◽  
Lithological Composition

The complex results of petrophysical testing of rocks, taken from prospecting-development wells of Duvanni-deniz, Sangachal-deniz, Bulla-deniz, Garasu and etc. areas, where the sediments of productive stratum are widely expanded, have been given. Average values of granulometric composition of rocks of productive unit of the above areas by the section have been recounted. The problem of dependence of permeability on porosity and depth was solved. Dependence between physical parameters for the individual kinds of rocks, dependence between physical properties and material structures are established. The results of various petrophysical research methods show that the filtration capacitance properties, in general, deteriorate with depth. However, in certain cases, in clay and carbonate rocks, reservoir properties can improve, due to the appearance of secondary porosity under relatively stringent thermobaric conditions. The histograms, which consist of average values of granulometric composition of productive stratum rocks when crossing some places of archipelago are constructed, the problems of dependence of permeability on porosity and depth were solved. The researches showed, that the physical process of the same- named and same-aged features rocks change in the result of geological-physical processes, getting different values. It's noticed, that the porosity and permeability are increasing from north-west to south-east by changing lithological composition.

scholarly journals New data on lithology, organic geochemistry and accumulation conditions of the Bazhenov formation in Western Siberia

Georesursy ◽  
2019 ◽  
Vol 21 (2) ◽  
pp. 129-142 ◽  
Author(s):  
Vika G. Eder ◽  
Elena A. Kostyreva ◽  
Anna Yu. Yurchenko ◽  
Natalia S. Balushkina ◽  
Inga S. Sotnich ◽  
...  
Keyword(s):  
Organic Matter ◽  
Carbonate Rocks ◽  
Western Siberia ◽  
Organic Geochemistry ◽  
Carbonate Content ◽  
Reservoir Properties ◽  
Bottom Part ◽  
Bazhenov Formation ◽  
Lithological Composition ◽  
Transformation Of Organic Matter

This paper presents data on lithological composition, distribution, reservoir properties, geochemistry of organic matter and genesis of carbonate rocks of the Bazhenov formation within the central part of Western Siberia (the region of the Khantei hemianteclise). The following types of carbonates are distinguished: a) primary biogenic – shell rock interlayers and residues of coccolith; b) dia- and catagenetic – in varying degrees, recrystallized rocks with coccoliths, nodules and aporadiolarites; c) catagenetic – cracks healed with calcite in limestone of the foot of the Bazhenov formation. It was determined that the crystallization of the carbonate material of nodules took place in various conditions: in the bottom part of the sediments and in the later stages of diagenesis. The source of calcite for nodules was calcareous nanoplankton or bivalve shells. The carbonate content of the cuts decreases in the following sequence: Yuzhno-Yagunsky → Povkhovsky → Novortyagunsky → Druzhny areas, which are associated both with facial features and various physicochemical conditions of diagenesis and catagenesis. Transformation of organic matter increases in the northeast direction from South Yagunsky to Povkhovsky area, which is confirmed by molecular parameters of catagenesis. The carbonate rocks of the bottom part of the Bazhenov formation in the South Yagunsky area are similar in structure to the main oil-bearing reservoirs of the Salym and Krasnoleninsky fields.

Predicting subsurface CO2 movement: From laboratory to field scale

Geophysics ◽  
2012 ◽  
Vol 77 (3) ◽  
pp. M27-M37 ◽  
Author(s):  
Ranjana Ghosh ◽  
Mrinal K. Sen
Keyword(s):  
Elastic Properties ◽  
Carbonate Rocks ◽  
Water Saturation ◽  
Time Lapse ◽  
Carbonate Reservoir ◽  
S Wave ◽  
Permeability Enhancement ◽  
Proposed Model ◽  
Porosity And Permeability ◽  
Frequency Dependent Model

Finding an appropriate model for time-lapse seismic monitoring of [Formula: see text]-sequestered carbonate reservoir poses a great challenge because carbonate-rocks have varying textures and highly reactive rock-fluid system. We introduced a frequency-dependent model based on Eshelby’s inclusion and differential effective medium (DEM) theory that can account for heterogeneity in microstructure of rocks and squirt flow. We showed that the estimated velocities from the modified DEM theory match well with the laboratory measurements (ultrasonic) of velocities of carbonate rocks saturated with [Formula: see text]-rich water. The theory predicts significant decrease in saturated P- and S-wave velocities in the seismic frequency band as a consequence of porosity and permeability enhancement by the process of chemical dissolution of carbonates with the saturating fluid. The study also showed the combined effect of chemical reaction and free [Formula: see text] saturation on the elastic properties of rock. We observed that the velocity dispersion and attenuation increased from complete gas saturation to water saturation. The proposed model can be used to invert geophysical measurements to detect changes in elastic properties of a carbonate reservoir and interpret the extent of [Formula: see text] movement with time. These are the key elements to ensure that sequestration will not damage underground geologic formation and [Formula: see text] storage is secure and environmentally acceptable.

scholarly journals POROSITY AND PERMEABILITY PROPERTIES OF CONSOLIDATED ROCKS OF THE NORTHERN NEAR EDGE ZONE OF THE DNIEPER-DONETSK DEPRESSION

2021 ◽  
pp. 37-45
Author(s):  
S. Vyzhva ◽  
V. Onyshchuk ◽  
I. Onyshchuk ◽  
M. Reva ◽  
O. Shabatura
Keyword(s):  
Permeability Coefficient ◽  
Water Saturation ◽  
Effective Porosity ◽  
Integrated Analysis ◽  
Residual Water ◽  
Edge Zone ◽  
Reservoir Conditions ◽  
Porosity Coefficient ◽  
Porosity And Permeability ◽  
Saturation Factor

Paper concerned the researches of porosity and permeability properties of consolidated rocks (siltstones, poor-porous sandstones) of the northern near edge zone of the Dnieper-Donetsk depression. The purpose of the research was to study the petrophysical parameters of the consolidated reservoir rocks, as the basis of the integrated analysis of their physical properties. Such reservoir parameters as the open porosityfactor and void factor, permeability coefficient and residual water saturation factor were studied. Void structure of rocks with capillarimetric method was studied. The relationship of the density of rocks with their porosity was also studied. The porosity study was carried out in atmospheric and reservoir conditions. The bulk density of dry rock samples varies: for siltstones from 2232 kg/m3 to 2718 kg/m3 (mean 2573 kg/m3 ), for sandstones from 2425 kg/m3 to 2673 kg/m3 (mean 2555 kg/m3); water saturated rocks – for siltstones from 2430 to 2727 kg/m3 (mean 2622 kg/m3 ), for sandstones from 2482 kg/m3 to 2688 kg/m3 (mean 2599 kg/m3 ). An apparent specific matrix density varies: for siltstones from 2645 to 2740 kg/m3 (mean 2683 kg/m3 ), for sandstones from 2629 kg/m3 to 2730 kg/m3 (mean 2664 kg/m3). The open porosity coefficient of studied rocks, in a case they were saturated with the synthetic brine, varies: for siltstones from 0,008 to 0,074 (mean 0,034), for sandstones from 0,013 to 0,087 (mean 0,041), if samples were saturated with nitrogene (N2) then it varies: for siltstones from 0,013 to 0,076 (mean 0,040), for sandstones from 0,022 to 0.095 (mean 0.052). The effective porosity factor has following values: for siltstones 0,0003–0,0050 (mean 0,00026), for sandstones 0,0013–0,0293 (mean 0,0048). Analysis of reservoir conditions modeling revealed that porosity coefficient varies: for siltstones from 0,007 to 0,060 (mean 0,028), for consolidated sandstones from 0,011 to 0,081 (mean 0,037). Due to the closure of microcracks under rock loading reduced to reservoir conditions the porosity decreases in comparison with atmospheric conditions, which causes a relative decrease in the porosity coefficient for siltstones from 14 to 19,5 % (mean 17,0 %), for sandstones from 7,5 to 18.0 % (mean 10,5 %). Capillaryometric studies by centrifuging determined that the void space of the studied rocks has the following structure: for siltstones, the content of hypercapillary pores varies from 1 to 6 % (mean 3 %); the content of capillary pores – from 1 to 11 % (mean 5 %), the content of subcapillary pores – from 84 to 97 % (mean 92 %); for sandstones, the content of hypercapillary pores varies from 1 to 18 % (mean 4%); content of capillary pores – from 2 to 40 % (mean 10 %), the content of subcapillary pores – from 43 to 96 % (mean 86 %). According to the results of laboratory measurements of the permeability coefficient, this parameter varies: for siltstones from 0,002 fm2 to 1,981 fm2 (mean 0,279 fm2 ), for sandstones from 0,002 fm2 to 1,492 fm2 (mean 0,176 fm2 ). The correlation analysis has allowed to establish a series of empirical relationships between the reservoir parameters (density, porosity coefficient, permeability coefficient, effective porosity factor and residual water saturation factor). These relationships can be used in the data interpretation of geophysical studies of wells and in the modeling of the porosity and permeability properties of consolidated rocks of the northern near edge zone of the Dnieper-Donetsk depression.

scholarly journals ON THE POSSIBILITY OF WETTABILITY ASSESSMENT OF OIL AND GAS RESERVOIRS BY THEIR MAIN COLLECTOR PROPERTIES

2020 ◽  
Keyword(s):  
Film Thickness ◽  
Oil And Gas ◽  
Water Saturation ◽  
Core Material ◽  
Residual Water ◽  
Laboratory Studies ◽  
Practical Application ◽  
Reservoir Properties ◽  
Standard Methods ◽  
Water Holding

Problem statement. In some publications, the possibility of determining the wettability according to geophysical studies of wells (GIS), in particular, defined in the complex GIS residual water saturation or water retention capacity. As the main quantitative indicator of wettability, the thickness of the fictitious film of residual water is used. If this idea is true, then the calculation of wettability is possible and the results of determining the same parameters in the course of laboratory studies of core material. The purpose of this work is to test the proposed method for calculating wettability on the basis of data on the main reservoir properties of rocks obtained in the laboratory and to assess the possibility of practical application of this technique. Scientific and practical significance. The wettability of the rock surface is an important parameter on which the main indicators of the development of hydrocarbon deposits depend. At the moment, many oil and gas companies are experiencing difficulties in developing long-term fields. This is a breakthrough of water during water flooding, selective flooding of the wells and increased water-repellency of the reservoir in the development process. Taken together, this leads to a decrease in the rate of hydrocarbon extraction, a significant increase in flooding and, as a result, to a decrease in the final indicators of hydrocarbon recovery and significant economic losses. There are many methods of influencing the oil and gas reservoir in order to obtain a cost-effective inflow of hydrocarbons. But whatever method was used, there is a question of control and adjustment of wettability, the solution of which is impossible without determining the real relative wettability of the reservoir with water and hydrocarbons. Core material, which can determine the wettability of standard methods, is not selected enough and the possibility of calculating the wettability of GIS data could fundamentally improve the situation. Analysis of available publications on the topic. In the course of the work, the theoretical background of the proposed technique, the conclusion of the formula for calculating the thickness of the dummy film and the data on practical application given in the available works were analyzed. According to the authors of the tested method, the degree of hydrophilicity of the productive formation is qualitatively characterized by the content of residual water: the higher its content, the more hydrophilic the rock. To quantify the degree of hydrophilicity, it is proposed to use the thickness of the fictitious film of residual water on the surface of pore channels, which should increase in direct proportion to the degree of hydrophilicity and which is determined by the values of the water-holding capacity of rocks. Materials of own researches. On the basis of laboratory studies, the results of which are presented in the article, it can be argued that the values of residual water saturation with increasing hydrophilicity can both increase and decrease. The relationship between residual water saturation and wetting angle is ambiguous and should be used with great care to assess the degree of hydrophilicity of rocks. Quantification of hydrophilicity on the thickness of the dummy film of residual water is complicated by the fact that, first, to determine the film thickness for water-holding capacity is highly problematic, they are too weakly bound, and secondly, the film thickness is poorly and ambiguously connected with the wetting, which used the wetting angle, and the index "M" defined by standard methods. Perhaps it is the proposed formulas for calculating the thickness of the fictitious film and the idea can be further developed, however, at this stage to replace the direct definition of wettability on the calculation of known values of reservoir properties is impossible. Conclusion. Calculation of wettability by known values of basic reservoir properties determined in laboratory conditions is impossible. We stipulate that this conclusion cannot be unconditionally transferred to the assessment of wettability according to GIS (determination of both residual water saturation and gas saturation coefficient according to GIS has its own specifics), but the impossibility of constructing the desired connections in the laboratory forces caution to approach such calculations. The performed work will help to avoid gross errors in the assessment of wettability, performed for various practical purposes, in particular, in the development of methods to prevent selective flooding of wells.

scholarly journals RESOURCE ASSESSMENT FEATURES OF NON-TRADITIONAL RESERVOIRS BY THE WELL-LOGGING DATA

2020 ◽  
pp. 59-64
Author(s):  
О. Karpenko ◽  
V. Mikhailov ◽  
I. Karpenko
Keyword(s):  
Cross Sections ◽  
Water Saturation ◽  
Data Interpretation ◽  
Well Logging ◽  
Resource Assessment ◽  
Residual Water ◽  
Gas Saturation ◽  
Lower Porosity ◽  
Tight Reservoirs ◽  
Lithological Composition

Possibilities of estimation of shale gas resource and gas of tight reservoirs with the use of the well-logging data on the example of typical gascondensate field in the southern side of the Dnieper-Donetsk Depression are considered. The peculiarity of such works at this stage of studying the prospects of unconventional hydrocarbon resources in Ukraine is the shortage of factual material regarding special geochemical analysis of the core from perspective intervals of well sections. Emphasis is placed on the application of data from the standard set of well-logging methods. Using the method of Q. Passy, the content of organic carbon (TOC) in the rocks within the intervals of drilled wells was estimated. The characteristics of the lithological composition of rocks and the gas saturation of the traditional type of reservoirs were taken into account in the well-logging data. In the absence of available core data on thermal maturity of the rocks within the identified promising thicknesses, gas resources were estimated in several scenarios. The peculiarities of the well-logging data interpretation in the case of cross sections of wells of gas-saturated rocks with capacitance characteristics below the limit are given. Dependencies of the type "porosity - permeability", "porosity - residual water saturation" should be used to establish a lower porosity and gas saturation limit for tight reservoirs. At the end of the article, recommendations for calculating of gas resources in non-conventional reservoirs are provided.

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