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carbonated-reservoirs
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Selecting a Surfactant for Wettability Alteration In Iranian Carbonate Reservoirs
, M.Sc. Thesis Sharif University of Technology ; Bastani, Daruoosh (Supervisor) ; Badakhshan, Amir (Supervisor)
Abstract
Fractured carbonate reservoirs are mostly oil-wet to intermediate-wet. Due to the negative capillary pressure of the matrix poor spontaneous imbibition of reservoir brine occurs in such reservoirs, and water flooding leads into early break through due to the high conductivity of the fracture network. Some surfactants have the ability to change the wettability of rock matrix toward water-wet state by adsorbing onto the rock surface. The phenomenon can result in spontaneous imbibition improvement and thereby increasing water flooding efficiency and recovery from fractured carbonate reservoirs. In this thesis the effect of some surfactants on the wettability of Iranian carbonate reservoir rocks...
Experimental Investigation of Acidizing in Natural Fractured Carbonates to the Optimum Injection Condition
, M.Sc. Thesis Sharif University of Technology ; Ayatollahi, Shahabodin (Supervisor)
Abstract
In many cases, oil and gas extraction from reservoirs due to damage and permeability reduction near wellbore is lower than optimum level and reduces the flow of oil into the well. In fact, formation damage is the collapse of natural condition of reservoirs, In addition to delaying production and increasing costs, it causes early desertification of wells. Well stimulation methods are used to solve this problem and increase production. One of the most effective ways to increase the production of wells is well acidizing. In this study, the acid performance of the fractured carbonate reservoirs has been investigated. In this type of reservoirs, due to the existence of high permeable paths of the...
A Carbonate Reservoir Characterization Using AVO Analysis on 3D Seismic Data
, Ph.D. Dissertation Sharif University of Technology ; Pishvaie, Mahmoud Reza (Supervisor) ; Javaherian, Abdolrahim (Supervisor) ; Nabi Bidhendi, Majid (Co-Advisor)
Abstract
In this project, some issues facing the application of AVO in carbonate reservoirs were studied,reviewed and discussed: physical relationships between elastic and reservoir rock properties to estimate compressional and shear wave velocities both on core measurements and well logging data, sensitivity analysis for Gassmann‐Biot and Kuster‐Toksoz rock physics models on the representative carbonate samples, lithology discrimination and reservoir characterization in carbonate intervals using AVO seismic attributes and specifically LambdaRho‐MuRho approach.The studied area (Azadegan Oil Field) is an area about 1174 km2 of 3D seismic data and was containing of six wells in the time of study. In...
Investigation of Rheological Behavior of Polymer on EOR in Carbonate Reservoir
, Ph.D. Dissertation Sharif University of Technology ; Ramazani Saadat Abadi, Ahmad (Supervisor) ; Emadi, Mohammad Ali (Supervisor)
Abstract
The major objectives of this study are to analytically and experimentally investigate the rheological behavior of polymers in the fractured carbonate medium based on the polymer solution properties and operational conditions. The intrinsic and apparent viscosity of high molecular weight-partially hydrolyzed poly (acrylamide) which is mainly used in enhanced oil recovery (EOR) processes hasbeen investigated in reservoir conditions. Since, the EOR efficiency of hydrolyzed poly (acrylamide) is very sensitive to the temperature and salinity of petroleumreservoirs; investigations have been carried out at different possible reservoirtemperatures using high saline polymer solutions. The parameters...
Investigating the Role of Molecular Diffusion on the Performance of Non-Equilibrium Gas Injection in One of the Fractured Reservoirs in Iran
, M.Sc. Thesis Sharif University of Technology ; Ghazanfari, Mohammad Hossein (Supervisor) ; Fatemi, Mobin (Supervisor)
Abstract
Major parts of Iran's oil reservoirs are fractured carbonates, which need time to produce oil due to their much lower permeability than sandstone reservoirs. Molecular diffusion mechanism is an efficient mechanism in oil recovery from fractured reservoirs under gas injection conditions. The main subject of this work is to investigate the role of molecular diffusion mechanism in the non-equilibrium gas injection project and its role in increasing the oil recovery rate in two southern fractured reservoirs located in the west of Iran, taking into account the capillary pressure, as well as the change of interfacial tension closely miscible conditions is also investigated through simulation. The...
Experimental investigation of dynamic asphaltene adsorption on calcite packs: The impact of single and mixed-salt brine films
, Article Canadian Journal of Chemical Engineering ; Volume 97, Issue 7 , 2019 , Pages 2028-2038 ; 00084034 (ISSN) ; Ghotbi, C ; Jafari Behbahani, T ; Bakhshi, P ; Sharif University of Technology
Wiley-Liss Inc
2019
Abstract
In this study, the dynamic adsorption of asphaltene on a calcite surface is investigated. This study investigates the effect of mixed-salt brines on asphaltene adsorption. The results of this work can facilitate the understanding of the complex wettability behaviour of carbonate reservoirs. All experiments were performed in porous media, which were sand-packs filled with calcite powder, to study the influence of the type and concentration of salt on adsorption. The experiments were conducted with asphaltene concentration of 500 mg/L for brines of NaCl, Na2SO4, and a mixture of the two at various ionic strengths. In addition, two tests were performed with an asphaltene concentration of 2000...
The impacts of silica nanoparticles coupled with low-salinity water on wettability and interfacial tension: Experiments on a carbonate core
, Article Journal of Dispersion Science and Technology ; Volume 41, Issue 8 , 2020 , Pages 1159-1173 ; Jamialahmadi, M ; Esmaeilzadeh, F ; Wood, D. A ; Ghazanfari, M. H ; Sharif University of Technology
Taylor and Francis Inc
2020
Abstract
Two main reservoir mechanisms that impact oil recovery factors are wettability alteration and interfacial tension (IFT) change. In this study, these two key mechanisms are evaluated experimentally for samples from the Asmari (carbonate) oil reservoir utilizing silica nanoparticles in the presence of low-salinity water. The nanofluid, rock formation and crude oil samples were prepared meticulously to ensure meaningful experimental could be conducted over a range of low-salinity conditions. The results show that across the range of salinities studied, the absolute value of zeta potential of nanofluids decreases with increasing total dissolved solids (TDS) in the water treated with silica...
Effects of low-salinity water coupled with silica nanoparticles on wettability alteration of dolomite at reservoir temperature
, Article Petroleum Science and Technology ; Volume 34, Issue 15 , 2016 , Pages 1345-1351 ; 10916466 (ISSN) ; Jamialahmadi, M ; Esmaeilzadeh, F ; Ghazanfari, M. H ; Sharif University of Technology
Taylor and Francis Inc
Abstract
Wettability alteration in porous media is one of the mechanisms for enhancing oil recovery through injecting low-salinity water into carbonate reservoirs, in which active ions can remove the carboxylic oil component from the rock surface, altering the rock's wettability toward a water-wet condition. This study investigated the concomitant effects of low-salinity water and hydrophilic SiO2 nanoparticles on oil-wet dolomite rock. Results revealed that low-salinity water coupled with hydrophilic nano-SiO2 in oil-wet dolomite rock remarkably affected the wettability alteration of the rock, showing that the simultaneous presence of ions in water and hydrophilic nano-SiO2 led to considerable...
Characterization and estimation of reservoir properties in a carbonate reservoir in Southern Iran by fractal methods
, Article Journal of Petroleum Exploration and Production Technology ; Volume 8, Issue 1 , 2018 , Pages 31-41 ; 21900558 (ISSN) ; Bagheri, M ; Masihi, M ; Sharif University of Technology
Springer Verlag
2018
Abstract
Reservoir heterogeneity has a major effect on the characterization of reservoir properties and consequently reservoir forecast. In reality, heterogeneity is observed in a wide range of scales from microns to kilometers. A reasonable approach to study this multi-scale variations is through fractals. Fractal statistics provide a simple way of relating variations on larger scales to those on smaller scales and vice versa. Simple statistical fractal models (fBm and fGn) can be useful to understand the model construction and help the reservoir structure characterization. In this paper, the fractal methods (fGn and fBm) have been applied to characterize and to estimate of reservoir properties....
Smart water flooding performance in carbonate reservoirs: an experimental approach for tertiary oil recovery
, Article Journal of Petroleum Exploration and Production Technology ; Volume 9, Issue 4 , 2019 , Pages 2643-2657 ; 21900558 (ISSN) ; Ayatollahi, S ; Bahari Moghaddam, M ; Sharif University of Technology
Springer
2019
Abstract
Smart water flooding as a developing technique utilizes modified water chemistry in terms of salinity and composition to prepare the best-suited brine composition for a specific brine/oil/rock system to obtain higher oil recovery efficiency. Huge amount of unrecovered oil is expected to be remained in carbonate reservoirs; however, few research works on incremental oil recovery during smart water injection in carbonate cores at reservoir condition are reported. Several core flooding tests using one of the Iranian carbonate reservoir rock are conducted to check the effectiveness of smart water injection for more oil recovery efficiency. The results reaffirm the positive effect of sulfate ions...
Microorganisms’ effect on the wettability of carbonate oil-wet surfaces: implications for MEOR, smart water injection and reservoir souring mitigation strategies
, Article Journal of Petroleum Exploration and Production Technology ; Volume 10, Issue 4 , 2020 , Pages 1539-1550 ; Ayatollahi, S ; Sharif University of Technology
Springer
2020
Abstract
In upstream oil industry, microorganisms arise some opportunities and challenges. They can increase oil recovery through microbial enhanced oil recovery (MEOR) mechanisms, or they can increase production costs and risks through reservoir souring process due to H2S gas production. MEOR is mostly known by bioproducts such as biosurfactant or processes such as bioclogging or biodegradation. On the other hand, when it comes to treatment of reservoir souring, the only objective is to inhibit reservoir souring. These perceptions are mainly because decision makers are not aware of the effect microorganisms’ cell can individually have on the wettability. In this work, we study the individual effect...
Application of artificial neural network for estimation of formation permeability in an iranian reservoir
, Article 1st International Petroleum Conference and Exhibition, Shiraz, 4 May 2009 through 6 May 2009 ; 2009 ; Masihi, M ; Fatholahi, S ; Sharif University of Technology
European Association of Geoscientists and Engineers, EAGE
2009
Abstract
The permeability is one of the most important reservoir parameters and its accurate prediction is necessary for reservoir management and enhancement. Although many empirical formulas are derived regarding permeability and porosity in sandstone reservoirs [1], these correlations cannot be modified accurately in carbonate reservoir for the wells which are not cored and there is no welltest data. Therefore estimation of these parameters is a challenge in reservoirs with no coring sample and welltest data. One of the most powerful tools to estimate permeability from well logs is Artificial Neural Network (ANN) whose advantages and disadvantages have been discussed by several authors [2]. In this...
Simulation study of Conventional Fire Flooding (CFF) in fractured combustion cells: A promising tool along experiment
, Article 1st International Petroleum Conference and Exhibition, Shiraz, 4 May 2009 through 6 May 2009 ; 2009 ; Kharrat, R ; Ghotbi, C ; Sharif University of Technology
European association of geoscientists and engineers, EAGE
2009
Abstract
The Conventional Fire Flooding (CFF) process application feasibility on fractured carbonated reservoirs remained questionable. In this paper first combustion parameters and reaction kinetics of a naturally fractured low permeability carbonated heavy oil reservoir in Iran called Kuh-E-Mond applied to simulation study. After that, simulator has been validated with Kuh-E-Mond combustion tube experiment. Recovery mechanism in single block matrix is different from one in conventional model since oxygen first flows into the fractures and then diffuses from all sides into the matrix. Combustion of the oil in the fractures produces some water ahead of fracture combustion front which prohibits oxygen...
Application of a mathematical method in calculation of the skin variation during a real field acidizing operation
, Article Chemical Engineering Science ; Volume 192 , 2018 , Pages 829-839 ; 00092509 (ISSN) ; Jamshidi, S ; Jahangiri, H. R ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
The efficiency of an acidizing operation is usually assessed through ordinary well testing methods. These methods are performed only after the acidizing operation, and it is difficult to monitor and evaluate real-time efficiency of acidizing operation. Understanding the performance of the acidizing during the service, by analysis of the acidizing data is a viable approach to this costly and challenging process. The estimation of the skin changes needs an appropriate mathematical method that can handle the main aspects of an acidizing operation. It is tedious to model a real acidizing operation due to the heterogeneity of the reservoir, an unknown reaction rate of acid in reservoir condition,...
Predicting the rock wettability changes using solutions with different pH, through streaming potential measurement
, Article Journal of Petroleum Science and Engineering ; Volume 167 , 2018 , Pages 20-27 ; 09204105 (ISSN) ; Pahlavanzadeh, H ; Ayatollahi, S ; Manteghian, M ; Sharif University of Technology
Elsevier B.V
2018
Abstract
The high reactivity of the carbonate rocks at various pH makes it difficult to evaluate the wettability, hence to find the recovery mechanisms behind modified waterflood in carbonate reservoirs. More recently, the streaming potential measurement is introduced as a method of electrokinetic phenomena more relevant to the subsurface systems. Regarding few experimental studies and in order to improve our understanding on streaming potential measurement, the electrokinetic studies on quartz and calcite surface were conducted as a function of pH in the range of 1.5–11.5 using an in-house novel setup of streaming potential measurement. High sensitivity of streaming potential coupling coefficient to...
An atomistic insight into the implications of ion-tuned water injection in wetting preferences of carbonate reservoirs
, Article Journal of Molecular Liquids ; Volume 293 , 2019 ; 01677322 (ISSN) ; Badizad, M. H ; Ghatee, M. H ; Ayatollahi, S ; Sharif University of Technology
Elsevier B.V
2019
Abstract
The efficiency of water flooding methods is known to improve by applying ion-tuned water injection. Although there is a consensus that such improvement happens through reversing reservoir wettability characteristics to more water-wet state, the true impact of ions is still ambiguous among contradictory debates. The well-known molecular dynamics (MD) simulation techniques would shed light on such ambiguities to gain deep atomic-scale understanding of the process. Results from MD simulations show that the presence of Na+ and Cl¯ ions leads to the formation of an electrical double layer in adjacency of calcite surface while Mg2+ ions dominantly make complexes with hydrocarbons throughout the...
Introducing a method for calculating water saturation in a carbonate gas reservoir
, Article Journal of Natural Gas Science and Engineering ; Volume 70 , 2019 ; 18755100 (ISSN) ; Nabi Bidhendi, M ; Masihi, M ; Emamzadeh, A ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Cementation factor greatly affects water saturation estimation. Factors such as depositional environment, diagenesis and depositional architecture make the estimation of water saturation a big challenge in carbonate reservoirs. The current study is introduced a method for calculating cementation factor in Archie formula. First, (MRGC) technique was applied on the (NMR) logging parameters along with (NDS) data to obtain the optimum number of clustering. After that, fuzzy logic method was applied on conventional log parameters obtained from the wells without any NMR log data. In the third part of the study, a novel crossplot introduced including compressional to shear-wave velocity ratio...
Effect of salinity and ion type on formation damage due to inorganic scale deposition and introducing optimum salinity
, Article Journal of Petroleum Science and Engineering ; Volume 177 , 2019 , Pages 270-281 ; 09204105 (ISSN) ; Riahi, S ; Ayatollahi, S ; Mokhtari, R ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Smart water injection is recognized as an effective EOR process to alter the wettability and interfacial tension to obtain higher micro/macro sweep efficiencies. This water contains reactive ions such asMg2+, Ca2+ andSO42- which can act as potential-determining ions and change the surface charge of calcite rocks. One of the major concerns in the execution of an effective water-flood process, especially in tight carbonate reservoirs, is the chemical incompatibility between the formation brine and the injecting water. In the present study, laboratory fluid compatibility tests were carried out and software simulation was done to investigate the most important challenges of the water-flooding...
Mechanistic study of wettability alteration of oil-wet calcite: The effect of magnesium ions in the presence and absence of cationic surfactant
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 482 , October , 2015 , Pages 403-415 ; 09277757 (ISSN) ; Al Maamari, R. S ; Ayatollahi, S ; Mehranbod, N ; Sharif University of Technology
Elsevier
2015
Abstract
Over 60% of the world's discovered oil reserves are held in carbonate reservoirs, which are mostly naturally fractured. Conventional water flooding results in low oil recovery efficiency in these reservoirs as most of them are oil-wet. On account of negative capillary forces, injected brine cannot penetrate simply into an oil-wet matrix of fractured formations to force the oil out. Wettability alteration of the rock surface to preferentially more water-wet state has been extensively studied using both smart water and surfactants separately. This study aims to study the effects of Mg2+ as one of the most important wettability influencing ions on the wetting properties of oil-wet carbonate...
The impact of connate water saturation and salinity on oil recovery and CO2 storage capacity during carbonated water injection in carbonate rock
, Article Chinese Journal of Chemical Engineering ; 2018 ; 10049541 (ISSN) ; Riazi, M ; Ayatollahi, S ; Takband, M ; Sharif University of Technology
Chemical Industry Press
2018
Abstract
Carbonated water injection (CWI) is known as an efficient technique for both CO2 storage and enhanced oil recovery (EOR). During CWI process, CO2 moves from the water phase into the oil phase and results in oil swelling. This mechanism is considered as a reason for EOR. Viscous fingering leading to early breakthrough and leaving a large proportion of reservoir un-swept is known as an unfavorable phenomenon during flooding trials. Generally, instability at the interface due to disturbances in porous medium promotes viscous fingering phenomenon. Connate water makes viscous fingers longer and more irregular consisting of large number of tributaries leading to the ultimate oil recovery...