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Saint Petersburg 2018
- Conference date: April 9-12, 2018
- Location: Saint Petersburg, Russia
- Published: 09 April 2018
1 - 50 of 230 results
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The Adverse Effect of Monovalent Ions on Wettability Alteration Rate. A Case Study on Akanskoe Reservoir in Russia - Tatarstan
Authors M. Rezaei Koochi and A. ShakirovSummary- Modeling of hydraulic fracturing in carbonate reservoirs with horizontal wells, May 15–19, 2017 Kazan.
- A new downhole controlling system for chemical injections. Regional competition of student and postgraduate works of the Russian-Caspian region 2014. October 15–16, 2014, Moscow
- ADVANCED METHOD OF THERMO-GASO-CHEMICAL TREATMENT IN OIL FORMATIONS (UTGHV).
OIL PROVINCE, Publisher: Public organization “Volgo-Kamsk regional department of the Russian Academy of Natural Sciences” (Bugulma).EISSN: 2412–8910
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The Results of Advanced Methods of Interpretation of Seismic Data in Combination with GIS and the History of Development in Stratigraphic Traps
Authors A.V. Khitrenko, M.V. Plotnikov and K.A. BinkovSummaryStratigraphic and lithological traps of hydrocarbons became known almost simultaneously with structural ones, but despite this, directed explorations of hydrocarbon accumulations in such traps began to acquire relevance only in the last decade. The main reason for this was the difficulty in determining the correct distribution of collectors. The distribution of reservoirs and/or saturation in the reservoir is a fairly complex task in the interpretation process, even if there is qualitative background information (during fieldwork, processing, etc.).
Today, many oil and gas companies during the process of exploration the field are faced with situations when the hydrodynamic and/or geological models and the real picture are different. In this paper, authors are going to show a way of combining all available information and using additional interpretation technologies that are calibrated with GIS data and the development history of the deposit. With the help of complexification, the process of distributing reservoirs of stratigraphic and lithological types of traps becomes more accessible, and data analysis is more intuitive and consistent with geological concepts.
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Geochemical Characteristic of Aalenian (Middle Jurassic) Organic Matter in the Central Part of Polish Basin
Authors A. Zakrzewski, P. Kosakowski and A. KowalskiSummaryMiddle Jurassic organic-rich claystones and mudstones from the North Sea area are very good source rocks. Organic-rich rocks of the same age occur in Polish Basin. Middle Jurassic claystones and mudstones from Polish Basin have never been surveyed in the course of an extensive geochemical research. In this paper source rock potential of Aalenian horizon will be surveyed. In conducive cases these rocks may contain unconventional hydrocarbon accumulations.
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Methodological Approaches to the Evaluation of Oil Resources in the Bazhenov Formation
Authors M.B. Skvortsov, M.V. Dakhnova, E.A. Kopilevich, V.D. Nemova, N.D. Severe, A.M. Kirsanov and S.V. MozhegovaSummaryRegularities of distribution of oil in the Bazhenov formation are determined by the initial concentrations in the rocks of the organic matter (OM) and its catagenetic maturity, that is, the formation of effective reservoirs in the rocks directly related to the process of catagenetic transformation of OM. In this regard, the need to involve geochemical studies in the assessment of resources and reserves of the Bazhenov formation is obvious. Proposed methodological approaches for the selection of effective thicknesses involving data from geochemical surveys and geophysical well logging for evaluating resources.
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Comparison of Pore-Scale and Darcy-Scale Simulation of Acid Injection in Carbonate Formations
Authors B. Hosseinzadeh and Dr BazarganSummaryThe numerical study presented in this paper, based on the use of Darcy and Darcy-Brinkman equations in pore-scale and Darcy-scale, gives a better understanding of the wormholing phenomenon. We have shown that the fluid phase dispersion coefficients used by Panga et al., 2005 match pore-scale simulation results reasonably. However, the mass transfer coefficient is not properly predicted by semi-empirical model ( Panga et al., 2005 ) when compared with pore-scale simulation. Here importantly, Darcy equation is found to be non-applicable when used to predict the flow inside the wormholes created by acid injection into carbonate formations. This has been shown for two cases with and without wormholes. Thus, Darcy equation used by researchers to determine optimum conditions for acid injection is not accurate.
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Assessing 3D Structural Uncertainties in Reservoir Modeling and their Effects in Fluid Dynamics
By A. GanzoSummaryThe main purpose for building a subsurface model is not only for better understanding of the field subsurface but also to define and optimize the field development plan. Depending on the field, the available data, and the application that is used, different companies may have different workflows for building the subsurface model. In most cases, the main input data for building a 3D geological model are wells data and seismic data, which from both data an interpretation and/or extra calculation need to be done.In this study, two different 3D structural models of the studied field were built based on the uncertainty of the interpreted seismic faults; hence two fault models and geological models were created. These geological models were taken for flow simulation analysis where the impact of flow across some of the minor faults in the field productivity was investigated.An integrated static and dynamic reservoir modeling workflow is presented using JewelSuite Subsurface Modeling software to quickly build multiple 3D structure scenarios, address the effect of different stratigraphic zonation, different fault connectivity, and/or different fluid compartmentalization, carry on fluids volumes quantification and study their dynamics in the porous media.
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Nonstationary Temperature Processes Research Equilibrium Degasation of Oil in Well-formation System
Authors R.F. Sharafutdinov, R.A. Valiullin, T.R. Khabirov, I.G. Nizaeva and I.V. KanafinSummaryThe study of multiphase flows in boreholes is relevant, because in wellbore and formation flows are most often multiphase. The issue of temperature field formation in the well-layer system in conditions of oil degassing remains a little studied for today. Interpretation of temperature surveys in wellbores is performed at a qualitative level, quantitative estimates require the consideration of the influence of a large number of parameters. In oil production practice and during geophysical studies, the pressure in the wellbore may drop below the bubble point pressure. Under these conditions, oil degasses. Therefore, it is urgent to develop a mathematical model for two-phase oil and gas filtration and to study the main features of the temperature field in the “well-formation” system in conditions of oil degassing. In the article, a numerical solution of the system of equations describing the non-stationary motion of carbonated oil in the “well-layer” system is considered. The solution of the system of differential energy equations, mass conservation is made by the control volume method. The sensitivity of the mathematical model to the change in the following parameters has been studied: bubble point pressure, gas concentration, wellhead pressure and degassing heat.
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Planning of Geological Exploration Work to the Petroleum Resources Management Systems (PRMS) Standards
Authors L. Saratinian, S. Lats, S. Malov, N. Saratinian and A. KachkinSummaryThe exploration planning objects in LLC “LUKOIL-Western Siberia” are at different stages of exploration. Estimation of perspective resources changes in the process of studying the structure. It is based on available information and is subject to uncertainty. The volumes of reserves after opening may differ significantly from the PRMS estimate. It is also possible that geological exploration of geological exploration sites will not lead to a successful discovery. There is no absolute certainty that, provided that prospective resources are discovered, their development will prove to be economically viable.
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Comparative Analysis of Syn-Shear Structures on the Shelves of Arctic Seas (Based on CDP Seismic Data)
By Y. VasilyevaSummaryFrom CDP seismic data of 2013 – 2014, oblique slip, strike-slip, normal, reverse and thrust reverse faults were identified in the southwestern part of the Laptev Sea. Regional oblique slip and strike-slip faults are located with the distance of 60 – 80 km between them. They have northeastern strikes with the angles of about 30о, dextral displacements on the Siberian plate and sinistral displacements in the Laptev Sea rift system. The syn-shear pull-apart depression is probably the southern part of the Begichev trough of the Siberian plate with the dimensions of 60 × 20 km, as well as depressions of the West Laptev trough of the Laptev Sea rift system. The disjunctive dislocation system in the southwestern part of the Laptev Sea was compared with previously studied fault systems on the whole Laptev Sea shelf, on the Stokmanovsko-Luninsky threshold of the Barents Sea shelf and in the Taz Estuary of the Kara Sea. From comparative analysis, it was determined that the common features for the studied areas are predominantly northwestern strikes of normal and oblique slip faults and northeastern strikes of strike-slip faults, as well as the formation of pull-apart depressions at the neotectonic development stage.
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Order Filters: Some Aspects of the Intelligent Processing of Vibroseismic Research Data as Periodic Signals and Optimization of Their Performance
Authors V. Znak, D. Karavaev and P. TitovSummaryThis paper focuses on order statistic selection filters, where the filter output is restricted to be one of the input samples. In particular, we treat class of Weighted Order Statistic (WOS) filters, and the special filter class of Co-phased (CoPh WOS) filters. In the general case, the WOS filters possess a number of advantages in comparison with other filters, in particular, detail and edge preserving filters that are robust to outliers and sample contamination can be constructed. However, WOS filters are nonlinear and a theoretical analysis of their behavior is very difficult. Therefore, the using of the method of statistical trials for selecting the most effective project of the WOS filters (Data Mining) is drawing attention. Since this is time expensive, the increasing of computational productivity is of interest. In this paper, the technique of order filters adaptation invoking a method of statistical trials is considered, the approach to the attract graphical processors is presented, and results of processing a model of record of vibroseismic data are demonstrated.
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Hydrogeochemical and Geodynamic Conditions of West Siberian Megabasin Central Part Deep Horizons
Authors A. Kurchikov, A. Plavnik and M. ItskovichSummaryPaper compares the regularities of hydrogeochemical and geodynamic conditions in the areas of the central part of the West Siberian megabasin adjacent to the Koltogorsk-Tolkino suture zone. A significant difference of the spatial regularities for the individual components content and the general mineralization of groundwater is established, as well as for the hydrogeochemical conditions of the Aptian-Albian-Cenomanian, Neocomian and Jurassic aquifers. This characterizes the diverse impact of various geological and hydrogeological processes on the individual components content of the water-soluble groundwater complex. The absence of according between hydrogeochemical and tectonic conditions at the initial period of basin development has been established. The existence of connections for recent or active tectonic processes with the distribution of groundwater mineralisation for all aquifers is revealed.
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A Comprehensive Uncertainty Assessment of Wellbore Stability Models
Authors S.Sh. Tabatabaee Moradi, N. Nikolaev and A. KhormaliSummaryWellbore instability problems are often complicated and costly to solve and may endanger the success of the complete well construction process. For many years, different wellbore stability models are presented to study the state of stresses around the borehole and finally evaluate its stability or failure under the given circumstances. As the majority of the input parameters to the stability models are subjected to errors and uncertainties, therefore the model output, which is the minimum mud pressure required to prevent from the well collapse, is considered as an uncertain parameter. In this work, a Monte Carlo simulation as a quantitative probabilistic method is performed to assess the effect uncertainties in the input parameters on the performance of poroelastic stability model. Results of the Monte Carlo simulation for the given input parameters show that at mud pressures larger than 38 MPa, the probability of the wellbore stability is more than 90% and accordingly the wellbore collapse occurs with a probability of less than 10%. It also can be concluded that the probability of the well stability does not change significantly at different azimuth angles.
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Spatial Rocks Physical Properties Prediction by Applying Machine Learning Algorithms with Seismic 3D Data and Well Logs
Authors S.V. Egorov and I.I. PriezzhevSummaryThis paper investigate the possibility and effectiveness of using different machine learning algorithms to predict the spatial distribution of physical properties of rocks based on the joint analysis of 3D seismic data and well logs.
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Prediction of the Cross Section Below the Td by Means of the Versions of the VSP Method
More LessSummaryThe possibility of prediction of the geologic section below the TD distinguishes the method of vertical seismic profiling (VSP) from all other methods of geophysical researches of wells. In the VSP method the incident waves and waves reflected from the seismic boundaries, located under the bottom, are recorded simultaneously. Thus, in contrast to surface seismic exploration, a more correct solution of the inverse kinematic and dynamic problems, aimed for the study of the section below the bottom, is provided. Several versions of the VSP method are currently used, each of which has a number of advantages and disadvantages. The combination of different versions allows one to study the elastic properties of the subsurface and the section under the bottom of the well by using of kinematic and dynamic parameters of waves of different types and classes. In the report the standard versions of the VSP, such as zero-offset and offset VSP as well as non-standard version –moving source VSP having a number of obvious advantages over the offset VSP at the forecast of the section under the bottom of borehole, - are considered. Experimental and model results for solving geological and engineering problems are shown for various versions of the VSP method.
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A Comprehensive Study on Prediction and Inhibition of Calcium Sulfate Scale Formation in Oil Reservoirs
Authors A. Khormali and D.G. PetrakovSummaryThe deposition of inorganic salts in the bottomhole formation zone and on the surface of the oilfield equipment causes a reduction in the well production rate, service life and the rock permeability. The precipitation of calcium sulfate often occurs when mixing incompatible waters during waterflooding of reservoirs. In this work, conditions for the precipitation of calcium sulfate were determined depending on the reservoir conditions and the volume ratio of the injection and formation waters. The effects of reservoir temperature and pressure on the formation of calcium sulfate scale were studied. The results of scale prediction showed that with increasing temperature and decreasing pressure, the amount of forming calcium sulfate is significantly increased. To analyze the inhibition efficiency of calcium sulfate under static conditions, five different scale inhibitors were used. Results of studies on the evaluation of the efficiency of the developed scale inhibitor and industrial scale inhibitors under static and dynamic conditions were presented. The developed scale inhibitor has the highest efficiency for preventing the calcium sulfate scale formation at a concentration of 30 mg/L. Despite the decrease in solubility of calcium sulfate with increasing temperature, the effectiveness of the developed inhibitor does not significantly decrease with increasing temperature.
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Recall Factor in Reservoir Analogues Identification Problem
Authors G. Shishaev and S. SlivkinSummaryIn this research, we propose a new methodology for evaluation of recall factor in reservoir analogues identification problem. This factor provides the information about completeness of parameters set in order to identify ensemble of reservoirs. There could be various goals of analogues identification: geological similarity, PVT, production or something else. That is why it is important to know the precise volume of information, which should be provided. In this report data analysis techniques are performed for identification the essential set of parameters and providing the recall factor.
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A Method for 3D Ghost Attenuation in Case of a Rough Sea Surface
Authors M. Denisov and A. EgorovSummaryMarine seismic data contains ghost waves - reflections from the free surface that follow the source wavelet. These events worsen the resolution of seismic data. The techniques for the removal of these ghost waves exist, but they are often based on a flat-sea approximation. This approximation is invalid in case of bad weather conditions, when the sea surface is rough. We present a technology for the estimation of the sea surface shape and a deghosting method that is capable of taking this shape of the sea surface into account.
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Modeling of Unsteady Flow in Karst Reservoirs Using a Modified Brinkman’s Equation
Authors M.S. Jamal and A.A. AwotundeSummaryThe Brinkman’s equation simplifies the numerical modelling of karst reservoirs by allowing the use of a single transport equation to model the flow of fluids in both the free flow and porous regions, in effect reducing the error arising from improper modelling of the interface between the two regions. However, most of the equations available to model flow within karst reservoirs deal with steady flow conditions. This approach however may not be accurate in reservoirs where unsteady conditions exist. We considered the effects of unsteady flow conditions in karst reservoirs by adding an unsteady flow term to the Brinkman’s equation. We solved the coupled conservation-transport equations that models unsteady fluid transport in karst reservoirs and then studied the effects of unsteady flow conditions on tracer transport in two different sample reservoirs. The solution method adopted is sequential and involves solving the unsteady Brinkman’s model first, followed by advection-diffusion-adsorption equation using the cell-centred finite volume approach. The same problems were also solved using a steady flow Brinkman’s model, and the results obtained were compared. were compared. The results show that, inside the caves, the unsteady Brinkman’s model yielded lower tracer concentrations at early times when compared to the steady flow model.
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Simulation of Hydraulic Fracturing of Carbonate Reservoirs with Horizontal Wells
By A. KhormaliSummaryIn this work, the process of hydraulic fracturing in carbonate reservoirs with the horizontal wells was investigated developing a simulator by Eclipse. Therefore, the data of a carbonate reservoir were applied. The effects of different parameters on the hydraulic fracturing in the reservoir with horizontal wells were studied. An optimum point for fracture length and width in the horizontal wells was obtained based on the simulation results. This point showed an optimum fracture length and width of 70 m and 10 mm, respectively. In addition, change in the reservoir temperature during the hydraulic fracturing of the horizontal wells confirmed the optimum fracture length because the highest possible temperature was observed at 70 m of fracture length. Moreover, the simulation of total oil produced in a period of 30 years at different fracture angles showed the fracture angle has an important role during the production in horizontal wells. In this study, the maximum cumulative oil production occurred in a fracture angle of 100.
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Comparison of Structural Properties of Eastern & Western Fields of Frolovskaya Region
By D. PandeySummaryWestern Siberia is the highest oil and gas province in Russia. This technical paper describes the lithological properties of Bazhenov Formation which have been evaluated in two different wells of Frolovskaya Region of Western Siberia. The estimated thickness range of the formation is about 20 25 m and is highly rich in siliceous shale. Due to abnormal deviation in GR (gamma ray) and TNP (thermal neutron porosity) Log, some sections of the formations have been identified as oil & gas rich zones. Moreover, a comparative study has been made between these two wells after interpreting different Logs. Using these lithological properties, certain field development plans can be made to produce the wells
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Fracture Density Evaluation with the Use of Geomechanical Analysis
Authors E. Zubova and D. KonoshonkinSummaryFracturing model is required for reasonable development planning of fractured reservoirs. Discrete fracture networks (DFN) are generally used for these purposes. Input data relative to parameters of fracture systems at the interwell space particularly fracture density and direction are necessary for correct construction of DFN.
This work is dedicated to comparison of real fracture density and direction which were measured on outcropping with numerical simulation results and geomechanical parameters calculation relative to deformation and stresses. This comparison allows connection of geomechanical parameters with fracturing parameters and drawing of conclusion that geomechanical analysis is appropriate for fracturing prediction.
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The Ratios of the Main Stresses in the Wellbore in Carbonate Rocks
Authors M. Salimov and D. KonoshonkinSummaryThe efficiency of drilling is very important for oil companies. One of the most important areas of application of rock mechanics in drilling is the solution of the problem of failure of the walls of the wellbore. In this work, the case is considered when, at different depths, the shape of the wellbore breakouts changes from elliptical to toroidal. Based on the results of the analysis of the geomechanical model, it was shown that the change in the shape of the breakouts is associated with a change in the inclination of the well and the redistribution of stresses.
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Risks and Uncertainties Analysis in Geological Exploration
Authors V.Yu. Kerimov, A.V. Bondarev and R.N. MustaevSummaryOne of the main tasks facing geologists at different stages of geological exploration is the analysis of risks and uncertainties, to evaluate and minimize the consequences of which it is necessary to systematically study hydrocarbon systems and their elements - source rock, reservoirs, fluid, traps, and processes - generation, migration and accumulation of hydrocarbons.
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Investigation of Source Rock on the Results of the Complexing of Geochemical and Voltage Researches
Authors E.I. Vasilenko, A.V. Osipov, M.V. Zaharchenko and I.M. SalihovaSummaryWhen investigating and evaluating the generation potential of oil-bearing strata, the necessary parameter is the value of organic carbon, which is estimated by geochemical studies of well sections, which allows to analyze the carbon content of organic origin with high accuracy. However, its use is limited to core removal. In this paper, we discuss the results of using gamma-ray logging to evaluate organic carbon in complex geological and geophysical studies of the deep wells of the Volga-Ural NGP. The basis for this is the lithological and geophysical properties of the rocks, which form the sections of deep wells.
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Conditions for Forming and Prospects of Searching Hydrocarbon Deposits in the Kyulong Basin (Vietnam)
Authors V.N. Hai and E.A. LeonovaSummaryThe report examines the conditions for the formation and prospect of hydrocarbon deposits in the Kyulong basin (Vietnam). According to the results of the three-dimensional basin modeling, 44 clusters in the Miocene and Oligocene sediments have been identified, including 33 clusters corresponding to structures in various blocks in which reserves and 11 new clusters in the Kyulong basin were estimated.
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Organic Porosity - the Factor of Hydrocarbon Accumulations in the Source Rock
Authors V.Yu. Kerimov, M.V. Zaharchenko, M.M. Lyushin and R.N. MustaevSummaryThe report considers such factor of formation of hydrocarbon accumulations in oil-bearing strata as organic porosity. Organic porosity is a void space of organic origin, formed as a result of the transformation of organic matter and the generation of hydrocarbons. Organic porosity can be captured and measured not only by electron microscopy, but also calculated on the basis of pyrolytic parameters determined by the Rock-Eval method.
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Application of SWI and FWI for Building Near-surface Velocity Model and Improving Seismic Image Quality
Authors V. Korobkin, A. Burlakov, K. Kudryavtsev and D. TverdokhlebovSummaryBuilding near-surface velocity model for static computation has traditionally been a crucial step in land data processing. As PSDM technologies expanded, building an accurate shallow velocity model has become an important step in the construction of full PSDM velocity model. The most popular velocity modelling techniques are based on the analysis of refraction and reflection kinematics. Each of these techniques has its inherent limitations.
Refraction-based methods rely on the first break picking, which cannot always be done at the required quality level because of absorption, velocity inversions and interference with other types of energy. The use of reflected events is often impeded by limited offset range and low signal to noise ratio in the shallow intervals of data. Majority of the reflection-based methods make use of the kinematics of a single strong event, which often occurs at a substantial depth. Velocity distribution above this depth is approximated by a simplified model. Besides, the dynamics of data stay totally beyond the scope of these techniques.
The paper presents new near-surface modelling methods - Surface Wave Inversion and Full Waveform Inversion. Based on different physical principles, these methods overcome limitations of the conventional approaches and allow creating detailed and accurate velocity models.
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The 4D Regularization of Common-offset Seismic Data
Authors G.F. Zhernyak and V.V. MiroshnikovSummaryThis paper deals with the problems of common-offset series wave field interpolation. The common-offset field is computed using kinematical weighed traces moveout to the regular CMP bin grid with the (t,x,y,l) coordinates. If a bin summarized weight is below the threshold, then it remains empty. Regularization areas contours turn out to be very rough and contain sharp spikes and dips. This may result in artifacts rising with wave field migration. Uneven contours smoothing with spikes elimination and interpolation of empty bins is necessary. The 4D interpolation is carried out in the space-time frequency domain by the Minimum Weighed Norm Interpolation (MWNI) method. For improving the interpolation quality, spectra are counted using overlapped (t,x,y) windows. The problem of contours smoothing turns out to be ambiguous due to its multifactorial criteria.
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Carbonated Water Injection: a Green Solution for Heavy Oil Production
Authors M.J. Shokri Afra, M. Bahaloo, B. Rostami and H. NorouziSummaryThe performance of CWI is studied using five different oils by various viscosities through a series of high-pressure core flooding experiments. The results revealed the capability of CWI to recover higher incremental oil in comparison with water injection (WI). The creation of a low resistance flow channel and low oil recovery in WI, is compensated by CO2 diffusion from CW to oil, subsequent viscosity reduction and oil swelling during CWI. Also it found that higher reservoir oil viscosity has an adverse effect on WI and CWI performances which leads, the mobility ratio deviates from the ideal value and poor sweep efficiency causes lower oil recovery. Moreover, comparing the results of CWI and WI revealed that, nearly 28% oil recovery improvement was obtained in oil A, that reached 49.5% for oil E, with higher oil viscosity. This improvement demonstrated the advantage of CWI for heavy oil reservoirs. From the CO2 storage point of view, a remarkable fraction (ranges between 20% and 33% for different oils) of total volume of injected CO2 was stored at CWI. Thus, it was concluded that CWI has a great potential to permanently store the injected CO2 while significantly improving oil recovery in heavy oil systems.
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Testing the Resilience of the Rod-like Biopolymer Schizophyllan to Various Types of Mechanical Stressing
Authors G. Incera Garrido, F. Lehr, S. Mukherjee, D. Prasad, P. Aditama, S. Reimann, M. Ranft and B. ErnstSummaryThis paper addresses the mechanical stability of the biopolymer Schizophyllan for stressing conditions commonly occurring throughout an EOR process. Differences between laboratory and field testing and the importance of a realistic test design for a successful field application are highlighted. Analytical methods, challenges and learnings encountered during method development are also presented.
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Automatic Interpretation of Facies from Wireline Logs by Using Hierarchical Machine Learning Approach
Authors D.V. Egorov, N.V. Bukhanov, B.V. Belozerov and V.S. RukavishnikovSummaryThe objective of this research was examination of machine learning algorithms in combination with a priori geological information applicability for automatical facies distribution from wireline logs problem. This study was based on data from Field M located in Western Siberia which can be characterized by complex geology making results of examination reliable.
During the project different classification algorithms were evaluated to find the most appropriate one for automatical facies interpretation task. Classifiers were trained and tested on data from Field M, produced results were compared by different metrics.
At the next step chosen classifier (Random Forest algorithm) was used for comparison of two machine learning approaches - standard and hierarchical. The latter uses a priori geological information, in this study facies zonation map acted as such information. Application of this expert knowledge during automatical facies distribution allows separation of the initial data set into subsets to simplify classification task and improve prediction accuracy.
Finally, developed algorithm was performed on the entire oilfield including more than 700 wells to justify its applicability for real industry problems.
Previously mentioned steps were conducted with aid of originally developed Python script which can be integrated into any software environment to automate facies interpretation process.
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The Forecast of the Oil and Gas Presence in the Sedimentary Cover of the Northern Part of the Predverkhoyan Foredeep
More LessSummaryThe 2D seismic data and drilling results has been analyzed for the northern part of the Predverkhoyan foredeep. The stratigraphy, lithology and geochemistry studies have been carried out. The forecast of oil and gas presence has been fulfilled.
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Geochemical Estimation of Hydraulic Fracturing Efficiency in Non-conventional Reservoirs
Authors A.N. Moroshkin, A.Yu. Samoylenko, A.Y. Kuklinsky, A.V. Ermolovsky and N.N. PolskayaSummaryCurrently the directional drilling combined with hydraulic fracturing are the most promising and economically feasible mechanisms for shale oil and gas production. There are different methods of fracture distribution estimation resulting from hydraulic fracturing including geochemical ones. Abstract considers in general the stages of geochemical efficiency estimation of hydraulic fracturing in non-conventional reservoirs and shows the possibility of its complex use in determination of HC fluid appurtenance to the bed in development.
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Description of the Geological Structure and Hydrocarbon Potential of Lugovskogo License Area of the Barents Sea According to Seismic 3D
Authors V. Borodkin, A. Kurchikov, V. Samitova, A. Lukashev, A. Nedosekiv, O. Smirnov and A. PogretskiySummaryThe article describes the tectonic location of study area and position it with the point of view of petroleum-geological zoning, and the main oil and gas complex (NGK). In the Triassic, Jurassic and burrascano and the Aptian-Albian-Cenomanian NGK given seismological model, the conditions of formation of deposits, promising the facilities set the optimal amount of exploration drilling. The complex of symptoms reported the presence of processes of vertical migration of hydrocarbons contributing to the formation in the Cretaceous part of the section secondary of hydrocarbon deposits.
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Mathematical Modeling of Deep-bed Filtration of Dilute Suspension
By D. SidorovaSummarySome problems of deep-bed filtration of dilute particulate suspension are discussed. An inverse problem of kinetic coefficient identification as a function of suspension concentration and suspended particles relative size is considered with the use of published data for porous samples exeriments. Some exact solutions of flow of suspension through long porous sample are given.
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Fractures Clusterization Applying K-means Method Using Microimage Log Data for Fractures Characterization
Authors G. Burtsev, P.A. Kharitontseva and I.A. UzhegovaSummaryThe purpose of the work is the microimagers log data analysis.
Calculations were performed in Mathcad, Statistica and Excel software packages.
Nelson’s fractures classification was used for the completion of the fractures clusterization. Nelson’s fractures types distribution along the wellbore was acquired. The clusterization was done using k-means algorithm, whose description was also provided.
The methods used in the text can be used in the construction of fractured reservoirs geological models and for the considering of permeability anisotropy during reservoir simulation and well placement scheme design. Nelson’s fractures clusterization can help with the determination of reservoir dominate fractures type.
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Investigation of N2-Composition in CO2 Gas Mixture for EOR Purpose
Authors E. Ghanaatpisheh Senani, H. Behmanesh, S. Kord and S. BairamzadehSummaryIranian oil reservoirs were screened according to standard screening criteria. The CO2 flooding performance for the selected reservoirs was evaluated by CO2-Prophet at one hydrocarbon pore volume injection, and their recovery profile was compared together.
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3D Channel Reservoir Characterization Using a Model Selection Scheme for Fast and Reliable History Matching
More LessSummaryIn this study, we use ensemble Kalman filter (EnKF) for the optimization of the reservoir models. EnKF uses multiple models, which enable stochastic analysis of the parameters. However, analysis of a large number of models brings huge simulation costs. Also, even though the models are updated after applying EnKF, poorly-designed initial models still lead to wrong estimations.Our method is to select good initial models before applying the EnKF algorithm. We use principal component analysis (PCA) for hundreds of initial models to discover some common trends of the permeability distributions in the models. After projecting the models onto a 2D principal component plane, the model with the smallest error is selected as a representative and we choose 100 models near it for our history matching analysis. This process can reduce simulation time in EnKF as well as increase prediction quality on reservoir performances.We show our works in 3D channel reservoir case and the proposed method improves in both time and reliability of the analysis. What is more, since we use only a quarter number of initially generated 400 models, the simulation takes 75% less time when compared to the original case.
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Sensitivity Analysis of the Impact of Geological Uncertainties on DFN Model Construction (Field X)
Authors A. Bloshkin and P. KharitontsevaSummaryFractured reservoirs consist about 60% of the world’s proven oil reserves and 40% of the world’s gas reserves [ 1 ]. It is logically to suggest future interest increasing of production because most of highest classic clastic reservoirs are discovered and developed for many years. One of the prospective areas is basement of Western Siberia in Russia that have negligible amount of investigations.
Fractured reservoirs have complex lithology and composition comparing with clastic reservoirs. Understanding of fracture characteristics is necessary for oil and gas companies that spent huge amount of money with little effect. Many decisions lead to non-effective drilling and development strategies according to low level of knowledge about fractured reservoirs.
It is important to understand nature of fractured reservoir system, understand how fluid filtration is happened, what ways it used and what the main influence parameters on fluid flow.
Modelling of fractures reservoirs is useful tool for prediction behaviour of reservoir despite on many uncertainties during modelling. Reducing uncertainties and finding keys for knowing how modelling it is more fully leads to achieve optimum recovery and maximum profit for oil companies.
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Semi-Analytical Assessment of Condensate banking effects in Fracture Design and Optimisation of Gas-Condensate Reservoirs
More LessSummarySemi-analytical expression for the optimum fracture length is derived for single phase and two phase Darcy flow below and above the dew point pressure in which the effect of condensate banking was incorporated. Results showed that the proposed semi-analytical procedures reasonably coincided with the results obtained from the numerical simulation. These semi-analytical expressions, hence, can be used as simple and less-time consuming method to evaluate the optimum fracture lengths for gas-condensate systems.
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Reservoir Rock Anisotropy as the Main Factor Governing Wellbore Stability in West Salym Oilfield
Authors A.V. Seryakov, M.Yu. Podberezhny and O.B. BocharovSummaryWe present the results of the wellbore stability study performed for the West Salym oilfield with the help of the three-dimensional full coupled poroelastic modeling with mudcake dynamics taking into account. It was determined that isotropic model cannot describe the borehole behavior and the transversely-isotropic poroelastic equations were implemented into computational software. The anisotropic parameters were defined trough inversion task solution for the experimental data of core compression and then used for wellbore stability study. It was shown that vertical and inclined boreholes are stable under standard West Salym drilling conditions that is correlate with real observations. The admissible ranges of mud pressure changing without wellbore collapsing were determined. It was demonstrated that inclined borehole is more resistive against pressure drop changing than vertical.
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Inhibiting Asphaltene Precipitation Using Microwave Irradiation: Experimental Investigation
Authors J. Taheri-Shakib, A. Shekarifard and H. NaderiSummaryThis paper discusses the effect of microwaves on the flocculation of asphaltene particles. A sample of Dehlor heavy oil from southwestern Iran was exposed to microwave radiation under anoxic conditions and saturated with helium gas at intervals of 3, 6, and 9 minutes. Then, using a viscometer and normal heptane, the set point of asphaltene flocculation was determined for each sample. The results of the experiments showed that three minutes of exposure to microwave irradiation caused the asphaltene to be flocculated from 34 vol% normal heptanes in the crude sample to 41 vol%. In other words, microwaves inhibited asphaltene aggregation. Based on the results of SARA (Saturation, Aromatics, Resin, Asphaltene) analysis, the largest reduction in asphaltene composition in heavy oil occurred at the 3 min interval. In contrast, at 6 and 9 min, the greatest decrease was observed for resin compounds, which are themselves a natural inhibitor of flocculation. Changes in the structure and reduction of sulfur and nitrogen components of asphaltene also cause microwaves to act as an inhibitor in the flocculation of asphaltene particles. Therefore, reducing the amount of asphaltene compounds and eliminating polar compounds, which is a function of time interval for microwave radiation, delays asphaltene aggregation.
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Investigating Wettability Alteration of Heavy Oil Due to Microwave Radiation: Based on Changes of Polar Components
Authors J. Taheri-Shakib, Ali Shekarifard and Hassan NaderiSummaryWettability is one of the important parameters affecting the flow of fluid in a porous medium. Consequently, changes in wettability have been applied to increase the production of hydrocarbon reservoirs. This paper investigated the effect of microwaves on the wettability of a heavy-oil sample from a reservoir in southwestern Iran. For this purpose, the oil sample was exposed to microwaves using a Fischer assay at 5, 10, and 15 minutes in an environment free of oxygen and saturated with helium. Microwaving lowered the contact angle of the microwaved oil with oil-wet rock sample of the same reservoir from 104o to 71o. The microwaves reduced the oil’s tendency to spread over the rocks by affecting the sulfur (S), nitrogen (N), and oxygen (O) polar constituents and decreasing their amounts. Nitrogen decreased the most after 15 minutes of radiation (15.6%), followed by sulfur (14%) and oxygen (4.3%). Based on Fourier transform infrared (FTIR) results, cracking heavy compounds and creating lighter compounds due to microwave is another factor that changes the wettability of heavy-oil sample. The results of this study can be used as a representation of the use of microwave in hydrocarbon reservoirs to change the wettability and increase the production rate.
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The Experimental Study for Elimination of Asphaltene Precipitation in Porous Media in Solvent Injection Treatment: Based on the Appropriate Solvent Selection Criteria
Authors J. Taheri-Shakib, E. Kazemzadeh, M. Rajabi-Kochi, H. Naderi, Y. Salimidelshad and A. ShekarifardSummaryIn this study, after determining the set point of asphaltene flocculation by viscometer, 21 vol% of n-heptane and 79 vol% of crude oil were injected at 20 pore volume (PV) within three carbonate cores with a permeability of about 9 md. After precipitation of asphaltene in porous media, tetrahydrofuran (THF), chloroform (CF) and dichloromethane (DCM) solvents were injected into the cores at 4 PV to evaluate the permeability improvement. THF improved permeability by up to 70%. CF and DCM solvents restored permeability by 41% and 60%, respectively. The results of mapping and scanning electron microscopy (SEM) after injection of solvents showed that although THF improved permeability, the elements of nitrogen (N) and sulfur (S) remained in the porous media in place of the removed asphaltenes. In contrast, only small amounts of nitrogen remained with the DCM solvent. With CF, all three non-hydrocarbon polar elements – S, N and oxygen (O) – were present. Since the presence of these compounds in porous media causes more asphaltene to precipitate and form deposits, DCM is very suitable for this type of oil and rock according to the type of asphaltene.
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A Modified Investigation of WAT of Crude Oil Based on Wax Properties: Experimental Study
Authors J. Taheri-Shakib, M. Rajabi-Kochi, E. Kazemzadeh, H. Naderi and A. ShekarifardSummaryThis study investigated the effect of average carbon number and molecular/bonding characteristics of wax on wax appearance temperature (WAT) and wax crystal shape under microscope. Three samples of SAR, AS, and FAH from oil fields in southwestern Iran were analyzed. Their WAT values were measured using cross-polarized microscopy (CPM). The results showed that the average carbon number of the wax samples was in direct relation to WAT, with WAT increasing proportionately with increases in the average carbon number. The SAR sample with the highest average carbon number among the three samples showed a higher WAT than the other two. According to FTIR results, SAR and AS samples in their molecular structure, in addition to paraffinic compounds, slightly contain polar/naphthenic compounds. The presence of these structures in the wax molecule affected the interactions between the molecules of the wax and the interactions between the wax-asphaltene molecules, and increased the WAT. At 30oC below the WAT point, images taken from surface the oil samples were subjected to image processing. The SAR sample, which had the highest average carbon number, formed small, rod-shaped crystals, while the FAH sample with smallest average carbon number formed large, round crystals.
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To Determination of Formation Equilibrium Temperature from Temperature Measurements in Production Wells
Authors A.Sh. Ramazanov, R.A. Valiullin, R.Z. Akchurin, G.R. Vakhitova and I.G. NizaevaSummaryThe knowledge of the equilibrium formation temperature, geothermal gradient and heat flow is important for basin modeling and production logging in quantitative interpretation using simulators. Several approaches to determine the parameters of geothermal field according to the temperature measured in the wellbore are known. One of them is the measurement of temperature along special wells (scientific, control, piezometric). There is a way based on the registration of non-stationary temperature in the borehole after drilling. All these methods have well known disadvantages and they can be used only in a small number of wells of the interested oil fields.
We have proposed a method of determining the equilibrium formation temperature and geothermal gradient from thermal logs measured in producing wells. These measurements are carried out in large numbers of wells in oil and gas fields being developed. If the well has a sufficiently long sump (for producers it is more than 10 meters), then there is a zone near the bottom with undisturbed geotherm.
CFD modeling and analysis of downhole measurements made it possible to investigate the influence of confounding factors on the distribution of temperature in the sump: conductive heat transfer from the reservoir and metal casing, free heat convection.
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Optimized Production Method in an Oilfield laid South West of Iran: Evaluation and Selection
More LessSummaryUsing artificial lift is a method of production which is applicable in some conditions by considering the advantages and disadvantages. In this survey some wells are simulated by Pipesim software and different methods of production like down hole pumps and gas lift system was applied. As a result Electrical Submersible Pump (ESP) is a suitable method for artificial lift in this field.
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Experimental and Analytical Investigation on Effects of Different Mechanisms on Recovery of Bypassed Oil During Immiscible Methane Injection
Authors P. Abolhosseini, M Khosravi, B Rostami and M MasoudiSummaryLarge portion of oil might be bypassed due to reservoir heterogeneities. Several phenomena could recover the bypassed oil in matrixes; Marangoni is the most unfamiliar one which triggers a convective flow from a point with low interfacial tension to a point with high interfacial tension.In this study, Experimental and analytical tools were used to investigate the effect of thermal Marangoni flux on the enhancement of oil recovery during immiscible gas injection in a matrix-fracture system. Results of non-isothermal experiments have been compared with isothermal experiments (zero level of Marangoni flow) to study the presence of Marangoni flow. Analytical calculations of dimensionless numbers were implemented to study the dominant forces and mechanisms and as a result, the Marangoni flux does exist and has significant impact on the recovery of bypassed oil and also its magnitude is proportional to the absolute value of temperature gradient in oil/gas interface.
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Effect of Dispersion Coefficient and Frequency of Dead-end Pores on Bypassed Oil Recovery from a Matrix-fracture System
Authors D. Zeinabady Bejestani, B. Rostami, M. Khosravi and L. SabzaliSummaryThis study experimentally investigated the effects of dispersion coefficient and frequency of dead-end pores on bypassed oil recovery during CO2 injection in fractures at different miscibility regimes (first-contact miscibility, near-miscibility, and immiscibility); a special setup was designed and a series of CO2 injection experiments were performed using two different types of rocks. In the light of dimensionless analysis and tracer experiments the rule of different forces (viscous, gravity, and capillary), mechanisms (vaporization and swelling) and matrix properties (the effect of dispersion coefficient and frequency of dead-end pores) were studied. In all miscibility regimes, the oil recovery factor decreased as rock complexity (dispersion coefficient) and the frequency of dead-end pores increased or permeability decreased; thus, types of heterogeneity and pore space structure play significant roles in oil recovery and cause some oil to be left untouched by gas injection in remote dead-end pores. In rock types with a high frequency of dead-end pores, like carbonates, conventional oil-producing mechanisms are no longer effective; the role of the near-critical-point-wetting mechanism is thus more significant. As a result, the recovery factor values of the near-critical and the super-critical tests diverge from each other.
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Rock-Typing Feasibility Study on the Example of Clastic Gas Fiels: Main Challenges, Results and the Added Value
Authors G. Samotorova and C. DuvalSummaryNowadays reservoir models become more and more sophisticated in terms of methods and approaches used. The ultimate objective of a reservoir model is to obtain as accurate as possible estimation of hydrocarbon in place volumes, to capture impacting heterogeneities, and to be as much predictive as possible for dynamic units. This is achieved by a construction of 3D geological model populated with petrophysical properties. Rock-typing is one of the approaches allowing to populate a geologically coherent 3D model with petrophysical data.
The present rock-typing feasibility study has been performed on a clastic gas field, which reservoirs were formed in two distinct depositional environments - fluvial and tidal dominated. The study has included construction of static rock-types model per each interval, followed by the permeability modeling. The main complexity of the study was the poor quality of dataset (old exploration wells, with limited number and quality of acquired logs). Therefore, the challenge was the ability to correctly define and propagate rock-types to all well vintages.
This paper presents the main outcomes of the rock-typing feasibility study, as well as its added value for the reservoir characterization.
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