The Experts below are selected from a list of 30507 Experts worldwide ranked by ideXlab platform
Mingzhen Wei - One of the best experts on this subject based on the ideXlab platform.
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Combining Preformed Particle Gel and Low Salinity Waterflooding to Improve Conformance Control in Fractured Reservoirs
2018Co-Authors: Xindi Sun, Ali K. Alhuraishawy, Mingzhen WeiAbstract:Abstract The recovery from fractured reservoirs is usually low. The areal heterogeneity is one result of the fractured reservoir. Low salinity waterflooding (LSWF) and preformed particle gel (PPG) have recently drawn great interest from the oil industry. LSWF can only increase Displacement Efficiency, and it has little or no effect on sweep Efficiency whereas PPG can plug fractures and improve sweep Efficiency, but they have little effect on Displacement Efficiency. The coupled method bypasses the limitations of each method when used individually and improves both Displacement and sweep Efficiency. The main objective of this study was to determine whether the combining technologies can improve conformance control in fractured sandstone reservoirs. Before the study was conducted, the effects of low salinity waterflooding, number of fractures, and PPG strength were studied. The PPG was injected into the fracture at a flow rate 2.0 ml/min. Brine was injected at a different flow rate after PPG placement to test the effect of flow rate on the PPG’s plugging Efficiency. Laboratory experiments showed that the oil recovery factor and the Frrw increased when the concentration of injected brine changed from conventional salinity to low salinity and the areal sweep Efficiency was improved. However, the PPG extruded pressure decreased when the PPG swelled in a low-brine concentration. At a high-flow rate, there was no significant effect on the Frrw. Combining two different EOR technologies can improve Displacement and sweep Efficiency and, in turn, enhance conformance control.
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study of Displacement Efficiency and flow behavior of foamed gel in non homogeneous porous media
2015Co-Authors: Yanling Wang, Jiafeng Jin, Baojun Bai, Mingzhen WeiAbstract:Field trials have demonstrated that foamed gel is a very cost-effective technology for profile modification and water shut-off. However, the mechanisms of profile modification and flow behavior of foamed gel in non-homogeneous porous media are not yet well understood. In order to investigate these mechanisms and the interactions between foamed gel and oil in porous media, coreflooding and pore-scale visualization waterflooding experiments were performed in the laboratory. The results of the coreflooding experiment in non-homogeneous porous media showed that the Displacement Efficiency improved by approximately 30% after injecting a 0.3 pore volume of foamed gel, and was proportional to the pore volumes of the injected foamed gel. Additionally, the mid-high permeability zone can be selectively plugged by foamed gel, and then oil located in the low permeability zone will be displaced. The visualization images demonstrated that the amoeba effect and Jamin effect are the main mechanisms for enhancing oil recovery by foamed gel. Compared with conventional gel, a unique benefit of foamed gel is that it can pass through micropores by transforming into arbitrary shapes without rupturing, this phenomenon has been named the amoeba effect. Additionally, the stability of foam in the presence of crude oil also was investigated. Image and statistical analysis showed that these foams boast excellent oil resistance and elasticity, which allows them to work deep within formations.
Sh Ayatollahi - One of the best experts on this subject based on the ideXlab platform.
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phase behavior and interfacial tension evaluation of a newly designed surfactant on heavy oil Displacement Efficiency effects of salinity wettability and capillary pressure
2015Co-Authors: A A Dehghan, Mohsen Masihi, Sh AyatollahiAbstract:Abstract This work aims to discuss the results of wide ranges of laboratory investigations to evaluate the performance of a newly-formulated surfactant for heavy oil reservoirs in order to improve the microscopic sweep Efficiency after water flooding processes. In the first part, the specific behavior of the formulated surfactant including its salinity tolerance, interfacial tension, and optimum performance window was determined. Then, the application of surfactant solutions in real sandstone reservoir rocks was assessed for both oil-wet and water-wet cases. Besides, the effect of changing the capillary and viscous forces and interfacial tension on the residual phase saturations were characterized. According to the results, the newly formulated surfactant provides middle phase micro-emulsion and low IFT value (i.e., about 0.01 mN/m) in a salinity window around 150,000 ppm which indicates its proper performance at high salinity ranges. Both the relative volume and solubilization ratios demonstrate the proper values to be applied for real case applications. Monitoring the differential pressure response and the effluent states in both water-wet and oil-wet Berea sandstone cores represent an incremental residual heavy oil production after water flooding through the formation of the emulsified oil droplets in the effluent solutions by chemical slug flooding. Plotting the capillary desaturation curves for both wetting and non-wetting phases through different capillary numbers demonstrate a normal variation trend for the non-wetting phase (approximately a semi-log relationship), while the wetting phase is greatly affected by the capillary end effect and relative permeability variations in the porous medium. This useful information could be extended for the other similar cases of chemically enhanced heavy oil recovery processes.
Song Wang - One of the best experts on this subject based on the ideXlab platform.
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stability co2 sensitivity oil tolerance and Displacement Efficiency of polymer enhanced foam
2017Co-Authors: Peng Wei, Lin Sun, Song WangAbstract:This paper focuses on the benefits of polymers that contribute to foam flooding, such as foam stability, carbon dioxide (CO2) sensitivity, oil tolerance and Displacement Efficiency. From the results, polymer enhanced foam was found to have a high stability and an insignificant coalescence mainly because of the high viscous force and strong foam films. Some significant improvements of foam properties were observed in the polymer enhanced CO2 foam, especially in a supercritical state (16 MPa, 90 °C), and polymer enhanced foam showed remarkable oil tolerance because of the fact that the stable emulsion was uniformly dispersed in liquid films. Furthermore, polymer enhanced foam could promote mobility control and increase the liquid division and enhanced oil recovery in a strong heterogeneous formation.
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effects of interfacial tension and emulsification on Displacement Efficiency in dilute surfactant flooding
2016Co-Authors: Chengdong Yuan, Tao Tan, Jian Hui, Shuai Zhao, Song Wang, Yanli TangAbstract:This study provides an investigation on the effect of interfacial tension (IFT) and emulsification on Displacement Efficiency in dilute surfactant flooding. In previous studies, usually the surfactant concentration or type was changed to achieve different IFT levels. However, in this study, only one surfactant with a constant concentration of 0.2 wt% was used to obtain five surfactant formulations with different IFT levels of 101, 10−1, 10−2, 10−3, and 10−4 mN m−1 by changing the salinity of the salt water to eliminate the influence of the surfactant concentration or type. The emulsifying rates of the five surfactant formulations were measured. The emulsion stability was evaluated by measuring the backscattering and transmission light using a Turbiscan LAB. It turned out that the five surfactant formulations had a unique characteristic that their emulsifying ability successively decreased with the reduction of the IFT. These five surfactant formulations were used to evaluate the effect of the IFT and emulsification on the Displacement Efficiency by core flooding experiments. The results indicated that the obtained additional Displacement Efficiency decreased with the increase of the emulsification ability but increased with the reduction of the IFT, which confirms that the lower the IFT, the higher the Displacement Efficiency in dilute surfactant flooding. Simultaneously, the reduction of the IFT might have a more important role on improving Displacement Efficiency for residual oil after water flooding than emulsification since the additional Displacement Efficiency decreased with the increase of emulsification.
Yanling Wang - One of the best experts on this subject based on the ideXlab platform.
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Experimental Study of Key Effect Factors and Simulation on Oil Displacement Efficiency for a Novel Modified Polymer BD-HMHEC
2018Co-Authors: Chao Wang, Yanling Wang, Pengcheng Liu, Zhe YuanAbstract:Abstract A novel synthetic hydrophobically modified hydroxyethyl cellulose (HEC) using bromododecane (BD) was developed in our previous paper, which we denote as BD-HMHEC. A series of one dimensional core Displacement experiments were continually conducted to evaluate the key effect factors on the resistance factor (F R) and residual resistance factor (F RR) of BD-HMHEC solution, including polymer concentration, core permeability and injection rate. Results have shown that BD-HMHEC has higher F R and F RR and has much better oil Displacement performance than HEC during oil Displacement process. Meanwhile, compared with HEC flooding, the key effects on oil Displacement Efficiency of BD-HMHEC flooding were investigated, including polymer concentration, injection slug and injection rate. A numerical simulation study has been developed by the Computer Modelling Group (CMG) simulator. Results have shown that BD-HMHEC flooding could cause better oil Displacement Efficiency than HEC flooding at the same condition. As indicated by one dimensional core Displacement experimental results, the further incremental oil recovery of switching to BD-HMHEC flooding could increase by 7.0~8.0% after hydrolyzed polyacryamide (HPAM) flooding. The studies indicate that BD-HMHEC has great potential application during enhanced oil recovery (EOR) processes in oilfields
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experimental study of rheological properties and oil Displacement Efficiency in oilfields for a synthetic hydrophobically modified polymer
2017Co-Authors: Pengcheng Liu, Chao Wang, Yanling WangAbstract:In a previous study, we developed a synthetic hydrophobically modified hydroxyethyl cellulose (HEC) using bromododecane (BD), which we denote as BD-HMHEC. In this work, we continually investigate the rheological properties and its oil Displacement Efficiency in PuTao well area in Daqing oilfields, China. Results show that BD-HMHEC solution has good viscosification, thermal-resistance, salt-tolerance, shear resistance, and acid/alkali resistance. The storage modulus (G’) and the loose modulus (G”) of the BD-HMHEC solutions increase significantly with increasing BD-HMHEC concentration, and the solution becomes viscoelastic at a sufficiently high BD-HMHEC concentration. The core flooding results showed BD-HMHEC flooding improves oil recovery by 7–14% in comparison with HEC flooding at concentrations of 4,000 mg/L under equivalent conditions. Moreover, BD-HMHEC flooding improves oil recovery by 7–8% after conducting water and hydrolyzed polyacrylamide (HPAM) flooding. The oil Displacement mechanism of BD-HMHEC solutions is discussed based on a visual evaluation. The results indicate that BD-HMHEC flooding is a feasible means for improving oil recovery after water/HPAM flooding.
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study of Displacement Efficiency and flow behavior of foamed gel in non homogeneous porous media
2015Co-Authors: Yanling Wang, Jiafeng Jin, Baojun Bai, Mingzhen WeiAbstract:Field trials have demonstrated that foamed gel is a very cost-effective technology for profile modification and water shut-off. However, the mechanisms of profile modification and flow behavior of foamed gel in non-homogeneous porous media are not yet well understood. In order to investigate these mechanisms and the interactions between foamed gel and oil in porous media, coreflooding and pore-scale visualization waterflooding experiments were performed in the laboratory. The results of the coreflooding experiment in non-homogeneous porous media showed that the Displacement Efficiency improved by approximately 30% after injecting a 0.3 pore volume of foamed gel, and was proportional to the pore volumes of the injected foamed gel. Additionally, the mid-high permeability zone can be selectively plugged by foamed gel, and then oil located in the low permeability zone will be displaced. The visualization images demonstrated that the amoeba effect and Jamin effect are the main mechanisms for enhancing oil recovery by foamed gel. Compared with conventional gel, a unique benefit of foamed gel is that it can pass through micropores by transforming into arbitrary shapes without rupturing, this phenomenon has been named the amoeba effect. Additionally, the stability of foam in the presence of crude oil also was investigated. Image and statistical analysis showed that these foams boast excellent oil resistance and elasticity, which allows them to work deep within formations.
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influence of wettability alteration to preferential gas wetting on Displacement Efficiency at elevated temperatures
2015Co-Authors: Yanling Wang, Jiafeng Jin, Xiao ZhaoAbstract:Liquid condensation near the wellbore region may cause cessation of gas production in gas-condensate reservoirs when pressure drops lower than its dew point. It is believed that gas deliverability can be enhanced by altering the wettability of reservoirs to gas-wetting. In order to investigate the influence of wettability alteration on the Displacement Efficiency of gas-condensate, contact angle measurement and gas flood tests were conducted. Results show that core wettability can be altered from liquid-wetting to intermediate gas-wetting or preferential gas-wetting by the fluorosurfactants FG24 and FG90. The contact angles of brine and decane indicated that core wettability can be altered from liquid-wetting to preferential gas-wetting by FG24 at a concentration of 0.3%, and by FG90 at 0.5%. Surface free energy before and after core treatment was measured by Owen's two-liquid method, the results showing that core surface free energy sharply decreased from 70 to about 3 mN/m after FG24 treatment. Oil disp...
Mohsen Masihi - One of the best experts on this subject based on the ideXlab platform.
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phase behavior and interfacial tension evaluation of a newly designed surfactant on heavy oil Displacement Efficiency effects of salinity wettability and capillary pressure
2015Co-Authors: A A Dehghan, Mohsen Masihi, Sh AyatollahiAbstract:Abstract This work aims to discuss the results of wide ranges of laboratory investigations to evaluate the performance of a newly-formulated surfactant for heavy oil reservoirs in order to improve the microscopic sweep Efficiency after water flooding processes. In the first part, the specific behavior of the formulated surfactant including its salinity tolerance, interfacial tension, and optimum performance window was determined. Then, the application of surfactant solutions in real sandstone reservoir rocks was assessed for both oil-wet and water-wet cases. Besides, the effect of changing the capillary and viscous forces and interfacial tension on the residual phase saturations were characterized. According to the results, the newly formulated surfactant provides middle phase micro-emulsion and low IFT value (i.e., about 0.01 mN/m) in a salinity window around 150,000 ppm which indicates its proper performance at high salinity ranges. Both the relative volume and solubilization ratios demonstrate the proper values to be applied for real case applications. Monitoring the differential pressure response and the effluent states in both water-wet and oil-wet Berea sandstone cores represent an incremental residual heavy oil production after water flooding through the formation of the emulsified oil droplets in the effluent solutions by chemical slug flooding. Plotting the capillary desaturation curves for both wetting and non-wetting phases through different capillary numbers demonstrate a normal variation trend for the non-wetting phase (approximately a semi-log relationship), while the wetting phase is greatly affected by the capillary end effect and relative permeability variations in the porous medium. This useful information could be extended for the other similar cases of chemically enhanced heavy oil recovery processes.
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monitoring the effect of discontinuous shales on the surfactant flooding performance in heavy oil reservoirs using 2d glass micromodels
2014Co-Authors: Saber Mohammadi, Mohammad Hossein Ghazanfari, Mohsen Masihi, Riyaz Kharrat, Milad SaidianAbstract:Although most heavy oil reservoirs contain discontinuous shaly structures, there is a lack of fundamental understanding how the shaly structures affect the oil recovery Efficiency, especially during surfactant flooding to heavy oils. Here, an experimental study was conducted to examine the effect of discontinuous shales on performance of surfactant flooding by introducing heterogeneities to represent streaks of shale in five-spot glass micromodels. Results show that oil recovery in presence of shale streak is lower than in its absence. Based on the authors’ observations, the presence of flow barriers causes premature breakthrough of injected fluids and also an unstable Displacement front. As well, Displacement Efficiency of surfactant flooding is dependent strongly on the shale distribution configuration. Increasing shale content causes reduction of ultimate oil recovery and also severe fingering during water flooding while it compensates during surfactant flooding considerably. In shaly patterns, in the ...
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effect of small scale flow barriers heterogeneities and connate water on Displacement Efficiency of polymer floods to heavy oil reservoirs
2013Co-Authors: Saber Mohammadi, Mohsen Masihi, Mohammed Hossein Ghazanfari, Shapour VossoughiAbstract:This work concerns a fundamental understanding of how heterogeneities induced by flow barriers and connate water affect the Displacement Efficiency of polymer floods, which has rarely been studied in the available literature. Here, a series of water/polymer injection experiments to heavy oil performed on five-spot glass micromodels containing randomly distributed shale structures is presented. It has been found that macroscopic Efficiency of polymer flooding majorly depends on flow barriers distribution/configuration; shale content and geometrical characteristics; presence of connate water and wettability of medium. Microscopic pictures revealed that the main parts of connate water were trapped in some pores/throats near and especially behind the shale streaks; also, presence of connate water causes a reduction of sweep Efficiency due to premature breakthrough of displacing fluid in an oil-wet media. In absence of connate water, polymer solution could linger and stick to the pore walls to delay the time for a polymer to channel to the production site. Results of this work disclose requirements for a detailed geologic study of barrier size and distribution for successful design of EOR processes in heterogeneous reservoirs.