The Open Fuels & Energy Science Journal




(Discontinued)

ISSN: 1876-973X ― Volume 11, 2018

Preparation and Performance Evaluation of Alkali-resistant Gel-type Deep Profile Agent



Yazhou Zhou*, Daiyin Yin
College of Petroleum Engineering, Northeast Petroleum University, Daqing 163318, China

Abstract

Currently, most profile control agents would be degraded in strong alkaline condition. They could not be applied in ASP (alkaline, surfactant and partially hydrolyzed polyacrylamide) flooding. To solve this problem, a new kind of alkali-resistant gel for deep profile has been studied. Based on the profile control mechanism of profile agent and the crosslinking mechanism of the polymer, the selection of the chemical agent with different type and concentration was carried out in strong alkaline (pH=12), using ordinary polymer as the main agent, organic and inorganic chemical crosslinking agent. The performance evaluation, residual resistance factor and displacement experiment for the prepared profile agent were carried out. The results show that the profile agent weakly affected the interfacial tension of the ASP flooding. The gelation time could be tuned by adjusting the concentration of the delayed coagulant. The alkali-resistant profile agent with good plugging performance was suitable for deep profile control. When this profile agent was applied in the process of ASP flooding, it could adjust the liquid producing profile and improve the oil displacement efficiency, the recovery ratio was about 4% higher than ASP flooding. The field test of alkali-resistant gel-type profile agent shows that, this alkali-resistant profile agent can achieve good effect, it can enhance oil recovery by 3%.

Keywords: Alkali resistant, ASP Flooding, Deep profile control, Gel, Polymer.


Article Information


Identifiers and Pagination:

Year: 2016
Volume: 9
First Page: 21
Last Page: 27
Publisher Id: TOEFJ-9-21
DOI: 10.2174/1876973X01609010021

Article History:

Received Date: 10/2/2015
Revision Received Date: 16/06/2016
Acceptance Date: 29/06/2016
Electronic publication date: 12/08/2016
Collection year: 2016

Article Metrics:

CrossRef Citations:
0

Total Statistics:

Full-Text HTML Views: 869
Abstract HTML Views: 737
PDF Downloads: 189
ePub Downloads: 181
Total Views/Downloads: 1976

Unique Statistics:

Full-Text HTML Views: 551
Abstract HTML Views: 470
PDF Downloads: 132
ePub Downloads: 140
Total Views/Downloads: 1293
Geographical View

© Zhou and Yin ; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution-Non-Commercial 4.0 International Public License (CC BY-NC 4.0) (https://creativecommons.org/licenses/by-nc/4.0/legalcode), which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.


* Address correspondence to this author at the College of Petroleum Engineering, Northeast Petroleum University, Daqing 163318, Heilongjiang, China; Tel: 0459-6503654; E-mail: zhouyazhou720@163.com




1. INTRODUCTION

The ASP flooding technology is about to enter the promotion stage of industrialization in Daqing sandstone reservoir. Some test sites were quite successful. Comparing with water flooding, the oil recovery of ASP flooding technology could increase by more than 20% [1Carrero, E.N.; Queipo, N.V.; Pintos, S.; Zerpa, L.E. Global sensitivity analysis of alkali-surfactant-polymer enhanced oil recovery processes. J. Petrol. Sci. Eng., 2007, 58(01), 30-42.
[http://dx.doi.org/10.1016/j.petrol.2006.11.007]
-3Aalaie, J.; Vasheghani-Farahani, E. Swelling behavior of sulfonated polyacrylamide nanocomposite hydrogels in electrolyte solutions: comparison of theoretical and experimental results. Iran Polym. J. Eng. Edu., 2012, 21(03), 175-183.
[http://dx.doi.org/10.1007/s13726-012-0016-3]
]. For the reservoirs with high heterogeneity and thick main reservoir, the injected chemical liquid in the late ASP flooding seriously flow along the high permeable layer [4Wang, K.L.; Ding, Y.J.; Yan, Y.T.; Sun, L.B. Physical simulation of oil displacement effect by using ASP composite profile control agent. J. of Daqing Petrol. Inst., 2005, 29(01), 30-36.], leading to the futile circulation of chemical agents. The deep profile control technology could be applied in ASP flooding, which could significantly reduce the futile cycle of the ASP liquid in the high permeable layer, and increase the oil displacement efficiency of ASP flooding [5Zhang, K.; Qin, J.S.; Chen, X.L. Double action of Cr3+ gel on modifying profile and removing CaCO3 in ASP flooding. Petrol. Sci. Technol., 2010, 28(05), 445-457.
[http://dx.doi.org/10.1080/10916460902744562]
-9Liu, J.X.; Sui, C.B.; Lu, X.G.; Wang, R.J.; Wang, L.; Li, Q.; Wang, S.X. Mechanism analysis and evaluation of compatibility between profile control agent and “Surfactant/Polymer” system. Oilfield Chem., 2012, 28(01), 65-67.]. Presently, profile agents, such as HPAM/Cr3+, HPAM/Al3+ and HPAM/organic phenol, have poor stability due to the higher pH value, molecular shape could be easily changed in high pH, leading to the low gel strength in the reservoir [10Paul Willhite, G.; Zhu, H.J.; Natarajan, D.; McCool, C.S.; Green, D.W. Mechanisms causing disproportionate permeability reduction in porous media treated with chromium Acetate/HPAM Gels. SPE J., 2012, 07(01), 100-108.
[http://dx.doi.org/10.2118/77185-PA]
-12Lou, Z.B.; Li, D.S.; Fan, A.X.; Du, Z.X.; Song, X.B. Experimental evaluation and field application of pre-cross linked polymer particle flooding in eastern Wenliu block 25 of Zhongyuan oilfield. J. Southwest Petrol. Uni. (Sci. & Techn. Edition), 2012, 34(5), 125-130.]. Despite the polymeric particles have good alkali resistant, they could not well match the oil layer. At present, there is no successful experience to use for reference in alkali profile control system. Therefore, it is of great significance to research the alkali-resistant profile agent for improving oil recovery under condition of high pH value and the development effectiveness of ASP flooding [13Zhou, Y.L.; Jiang, H.Q.; Wang, C.; Sang, G.Q.; Liu, L. Experimental study on microscopic percolation mechanism of polymer microsphere profile control and flooding by nuclear magnetic resonance. J. Xi’an Shiyou Univ., 2013, 28(01), 70-75. [Natural Science Edition].-16Rao, P.; Wang, J.; Pu, C.S.; Ma, Z.Y.; Liu, P.P. Application of the compound indepth profile modification in Gasi oilfield E31 reservoir. Oilfield Chem., 2011, 28(4), 390-393.].

In this paper, based on the actual reservoir and development situation in ASP flooding testing area, Daqing x oilfield, the alkali-resistant profile agent was developed, using polymer as the main agent, and organic and inorganic chemical crosslinking agent, together with stabilizer. The performance evaluation, core liquidity experiment and displacement experiment for the prepared profile agents were carried out, and the profile control agent application has been given in field test.

2. EXPERIMENTAL INSTRUMENTS AND REAGENTS

2.1. Main Agents

Partially hydrolyzed polyacrylamide, NaOH and surfactants were taken from x block in Daqing oilfield. Metallic crosslinking agent was chromium acetate, organic crosslinking agents were phenol and methyl aldehyde. The salinity of simulated injection water and formation water were 5216.04 mg/L and 729.3 mg/L, respectively.

2.2. Experimental Cores

The cores were designed according to the PI1~3 oil layer of x oilfield. It has three layers, the size was 30cm×30cm×4.5cm, the permeability was about 300×10-3 μm2, 500×10-3 μm2, and 800×10-3 μm2, respectively. The well net was five point well pattern with four injection wells and one production well.

2.3. Experimental Oil

The oil was prepared by wellhead crude oil and aviation kerosene, its viscosity was 6.84 mPa•s.

3. SELECTION OF PROFILE AGENTS

In this paper, the alkali-resistant gel-type profile agent was studied by blending the polymer solution, metal crosslinking agent, and organic crosslinking agent to prepare profile agents. Under the action of the crosslinking agents, the constitutional units of polymer could be crosslinked, forming the spatial lattice structures with the resin filler from the organic crosslinking agent, which has high strength and alkali resistance.

Through optimizing polymer concentration and molecular weight, organic crosslinking agent type and concentration, metallic crosslinking agent type and concentration, stabilizer concentration, the alkali-resistant profile agent formulation has been determined. Taking the optimization of polymer concentration for example, the experimental result is shown in Fig.(1), the formative gel picture of different polymer concentrations is shown in Fig. (2).

Fig.(1)

The gel viscosity of different polymer concentrations.



Fig.(2)

The formative gel picture of different polymer concentrations.



With the increasing polymer concentration, the viscosity of gel system is increased, gelation time is shorten. This is because under certain conditions, the hydraulic radius of polymer molecule is curtained. As concentration of polymer increasing, the chance of the collision and winding of polymer molecules is large, the polymer molecules react with crosslinking agent is much, which increasing the force among the polymer molecules, and the viscosity of gel system increased.

According to experimental result, the composition of the alkali-resistant profile agent was as follows: partially hydrolyzed polyacrylamide: Mw=25000000, 1800~2000 mg/L; metallic crosslinking agent: 0.15% chromium acetate; organic crosslinking agents: 0.1% phenol and 0.08% methyl aldehyde; 0.2% NaCl. The gelation time of profile agent was 4~5 days and the viscosity of the gel was 2320~3510 mPa•s, the stabilization time was more than 60d, it can meet the deep profile requirements in the process of ASP flooding.

4. PERFORMANCE EVALUATIONS OF THE PROFILE AGENTS

4.1. Influence of the Profile Agent on the Interfacial Tension of ASP System

The preferred profile agent was added in to the ASP liquid (1.2% NaOH + 0.3% surfactant + 2000 mg/L polymer) and then the interfacial tension of the composite system was measured, the contrast of interfacial tension between ASP system and compound system was shown in Table 1.

Table 1

The contrast of interfacial tension between ASP system and compound system.




From the interfacial tension comparison of the ASP liquid and the composite systems after adding the profile agent, it could be seen that the profile agent had little effect on interfacial tension of the ASP system.

4.2. Influence of the Delayed Coagulant Concentration on the Gelation Time of the Profile Agent

If the gelation time of the alkali-resistant profile agent could be well controlled, the profile agent could be better applied in the oilfield practice [17Kazempour, M.; Alvarado, V. Geochemically based modeling of ph-sensitive polymer injection in berea sandstone. Energy Fuels, 2011, 250(09), 4024-4035.
[http://dx.doi.org/10.1021/ef200773h]
, 18Al-Wahaibi, Y.M.; Al-Wahaibi, T.K.; Abdelgoad, M.A. Characterization of pH-sensitive Polymer microgel transport in porous media for improving oil recovery. Ener. Sources Recover. Util. Environ. Eff., 2011, 33(11), 1048-1057.]. Gelatigenous performance in different delayed coagulant concentration was shown in Fig.(3).

Fig.(3)

Gelatigenous performance in different delayed coagulant concentration.



It could be seen from the experimental results that the gelation time prolonged with the increasing of the delayed coagulant concentration. When the delayed coagulant concentration of 0.2%, the gelation time was 366h (15 days). As the delayed coagulant had little effect on the viscosity of the profile agent after gelation, the gelation time could be prolonged by adjusting the concentration of delayed coagulant.

5. THE CORE FLOODING EXPERIMENT FOR ALKALI-RESISTANT PROFILE AGENT

5.1. The Core Flow Experiments

The results of core flow experiments was shown in Table 2.

Table 2

The result of plugging experiment.




It could be seen in Table 3 that the residual resistance factor greater than 50 under the pH value of 12 by core flooding experiment for the profile agent, which could meet the requirements of deep profile control for the ASP flooding.

5.2. Oil Displacement Experiment

Scheme 1: water flooding to 98% water cut;

Scheme 2: water flooding to 95% water cut + ASP system 0.4 PV + subsequent water flooding into 98%water cut;

Scheme 3: water flooding into 95% water cut + ASP system 0.15 PV + profile agent 0.035 PV + ASP system 0.25 PV + subsequent water flooding into 98% water cut. The formula of ASP system was 2000 mg/L polymer, 1.2% surfactant and 0.3% alkali. The results of oil displacement experiment were shown in Table 3.

Table 3

Oil displacement efficiency of three schemes.




It could be seen that the recovery ratio of ASP flooding with alkali-resistant profile agent enhanced by about 4% comparing with that of the ASP flooding. Therefore, the development effect of ASP flooding could be improved by using alkali-resistant profile agent in the process of ASP flooding.

Fig.(4)

The produced fluid proportions of different permeable layers.



In order to analyze profile control result of alkali resistance profile agent, parallel core which permeability was about 300×10-3 μm2, 500×10-3 μm2, and 800×10-3 μm2 has been used to carry out displacement experiment. In the experiment, the liquid production of different cores has been recorded, and the obtained produced fluid proportions in different stages were shown in Fig. (4).

From the produced fluid proportions of three different permeable layers, it could be seen that after adding the gel profile control system, the plugging capability of high permeable layer was enhanced. Based on ASP flooding, the produced fluid proportions of high permeable layer decreased about 18%; while moderateand and low permeable layers increased about 12% and 6%, respectively. So, the alkali resistance profile agent can improve liquid producing profile.

6. APPLICATION OF ALKALI-RESISTANT PROFILE AGENT

The average permeability of X block is 343×10-3 μm2. It started to ASP flooding in March 2014, the injection rate is 0.2PV/a. The effect of some production well was bad, this type wells mainly focused on the water injection well of the basic well pattern. Inefficient and invalid cycle of injection liquid was serious, the relative imbibition of high permeable layer was up to 69.2%. X block is divided into 1# test area and 2# test area. The alkali resistance profile control agent was injected in 1# test area in September 2015, and the injection pore volume is 0.035PV, the water cut classification is shown in Table 4, the water cut curves of two test area are shown in Fig. (5).

Table 4

Water cut classification in 1# test area.




Fig.(5)

Contrastion of water cut in 1#test area and 2#test area.



As is shown, after injecting alkali resistance profile control agent, the well number which water cut were less than 80% was from 19 up to 22, the number of wells which water cut were more than 90% was from 8 reduced to 1. The water cut of 1# test area is decreased greatly, the water cut is 4% less than 2# test area. So far, the recovery percent of 1# test area is 2.86% more than 2# test area.

CONCLUSION AND DISCUSSION

The composition of the alkali-resistant profile agent was as follows: polyacrylamide: Mw=25000000, 1800~2000 mg/L; metallic crosslinking agent: 0.15% chromium acetate; organic crosslinking agents: 0.1% phenol and 0.08% methyl aldehyde; 0.2% NaCl. The profile agent had little effect on the interfacial tension of ASP system, the gelation time could be tuned by adjusting the concentration of delayed coagulant. From the results of core liquidity experiment, the alkali-resistant profile could be seen that the residual resistance factor of the profile agent is greater than 50 in pH=12. The results of oil displacement experiment show that the recovery ratio of ASP flooding with alkali-resistant profile agent enhanced by about 4% comparing with that of the ASP flooding. The development effect of x oilfield field shows that, this alkali-resistant profile agent can be applied in the process of ASP flooding, and it can achieve considerable effect, it can enhance oil recovery by 3%.

CONFLICT OF INTEREST

The authors confirm that this article content has no conflict of interest.

ACKNOWLEDGEMENTS

This work was supported by the National Natural Science Foundation of China under Grant No. 51474071 and Graduate Students’ Innovative Research Projects of Northeast Petroleum University Grant No. YJSCX2014-009NEPU.

REFERENCES

[1] Carrero, E.N.; Queipo, N.V.; Pintos, S.; Zerpa, L.E. Global sensitivity analysis of alkali-surfactant-polymer enhanced oil recovery processes. J. Petrol. Sci. Eng., 2007, 58(01), 30-42.
[http://dx.doi.org/10.1016/j.petrol.2006.11.007]
[2] Cheng, J.C.; Wang, D.M.; Li, Q.; Yang, Z.Y. Field test performance of alkaline surfactant polymer flooding in Daqing oil field. Acta Petrol. Sin., 2002, 23(6), 37-40.
[3] Aalaie, J.; Vasheghani-Farahani, E. Swelling behavior of sulfonated polyacrylamide nanocomposite hydrogels in electrolyte solutions: comparison of theoretical and experimental results. Iran Polym. J. Eng. Edu., 2012, 21(03), 175-183.
[http://dx.doi.org/10.1007/s13726-012-0016-3]
[4] Wang, K.L.; Ding, Y.J.; Yan, Y.T.; Sun, L.B. Physical simulation of oil displacement effect by using ASP composite profile control agent. J. of Daqing Petrol. Inst., 2005, 29(01), 30-36.
[5] Zhang, K.; Qin, J.S.; Chen, X.L. Double action of Cr3+ gel on modifying profile and removing CaCO3 in ASP flooding. Petrol. Sci. Technol., 2010, 28(05), 445-457.
[http://dx.doi.org/10.1080/10916460902744562]
[6] Mukhopadhyay, P.; Sarkar, K.; Soam, S.; Kundu, P.P. Formulation of pH-responsive carboxymethyl chitosan and alginate beads for the oral delivery of insulin. J. Appl. Polym. Sci., 2012, 129(02), 835-845.
[http://dx.doi.org/10.1002/app.38814]
[7] Awasthi, A.K.; Meng, F.R.; Künzler, J.F.; Linhardt, J.G.; Papagelis, P.; Oltean, G.; Myers, S.A. Ethylenically unsaturated polycarbosiloxanes for novel silicone hydrogels: synthesis, end-group analysis, contact lens formulations, and structure-property correlations. Polym. Adv. Technol., 2013, 24(06), 557-567.
[http://dx.doi.org/10.1002/pat.3115]
[8] Zhang, L.M. Laboratory research on gel profile modification agent with high temperature resistance and alkali-tolerance. Petrol. Geol. Eng., 2007, 21(02), 87-89.
[9] Liu, J.X.; Sui, C.B.; Lu, X.G.; Wang, R.J.; Wang, L.; Li, Q.; Wang, S.X. Mechanism analysis and evaluation of compatibility between profile control agent and “Surfactant/Polymer” system. Oilfield Chem., 2012, 28(01), 65-67.
[10] Paul Willhite, G.; Zhu, H.J.; Natarajan, D.; McCool, C.S.; Green, D.W. Mechanisms causing disproportionate permeability reduction in porous media treated with chromium Acetate/HPAM Gels. SPE J., 2012, 07(01), 100-108.
[http://dx.doi.org/10.2118/77185-PA]
[11] Vargas-Vasquez, S.M.; Romero-Zerón, L.B.; MacMillan, B. Analysis of syneresis of HPAm/Cr(II) and HPAm/Cr(III) acetate gels through 1H nuclear magnetic resonance, bottle testing, and UV-vis spectroscopy. Petrol. Sci. Technol., 2009, 27(15), 1727-1743.
[http://dx.doi.org/10.1080/10916460802611564]
[12] Lou, Z.B.; Li, D.S.; Fan, A.X.; Du, Z.X.; Song, X.B. Experimental evaluation and field application of pre-cross linked polymer particle flooding in eastern Wenliu block 25 of Zhongyuan oilfield. J. Southwest Petrol. Uni. (Sci. & Techn. Edition), 2012, 34(5), 125-130.
[13] Zhou, Y.L.; Jiang, H.Q.; Wang, C.; Sang, G.Q.; Liu, L. Experimental study on microscopic percolation mechanism of polymer microsphere profile control and flooding by nuclear magnetic resonance. J. Xi’an Shiyou Univ., 2013, 28(01), 70-75. [Natural Science Edition].
[14] Zhang, T.K.; Zhao, F.L.; Hou, J.R.; Li, Y.H. Application performance of gel particle profile control agent IPG. Xi’an Shiyou Univ., 2011, 28(04), 376-379. [Natural Science Edition].
[15] Salarizadeh, P.; Abdollahi, M.; Javanbakht, M. Modification of silica nanoparticles with hydrophilic sulfonated polymers by using surface-initiated redox polymerization. Iran Polym. J. Eng. Edu., 2012, 21(10), 661-668.
[16] Rao, P.; Wang, J.; Pu, C.S.; Ma, Z.Y.; Liu, P.P. Application of the compound indepth profile modification in Gasi oilfield E31 reservoir. Oilfield Chem., 2011, 28(4), 390-393.
[17] Kazempour, M.; Alvarado, V. Geochemically based modeling of ph-sensitive polymer injection in berea sandstone. Energy Fuels, 2011, 250(09), 4024-4035.
[http://dx.doi.org/10.1021/ef200773h]
[18] Al-Wahaibi, Y.M.; Al-Wahaibi, T.K.; Abdelgoad, M.A. Characterization of pH-sensitive Polymer microgel transport in porous media for improving oil recovery. Ener. Sources Recover. Util. Environ. Eff., 2011, 33(11), 1048-1057.

Endorsements



"Open access will revolutionize 21st century knowledge work and accelerate the diffusion of ideas and evidence that support just in time learning and the evolution of thinking in a number of disciplines."


Daniel Pesut
(Indiana University School of Nursing, USA)

"It is important that students and researchers from all over the world can have easy access to relevant, high-standard and timely scientific information. This is exactly what Open Access Journals provide and this is the reason why I support this endeavor."


Jacques Descotes
(Centre Antipoison-Centre de Pharmacovigilance, France)

"Publishing research articles is the key for future scientific progress. Open Access publishing is therefore of utmost importance for wider dissemination of information, and will help serving the best interest of the scientific community."


Patrice Talaga
(UCB S.A., Belgium)

"Open access journals are a novel concept in the medical literature. They offer accessible information to a wide variety of individuals, including physicians, medical students, clinical investigators, and the general public. They are an outstanding source of medical and scientific information."


Jeffrey M. Weinberg
(St. Luke's-Roosevelt Hospital Center, USA)

"Open access journals are extremely useful for graduate students, investigators and all other interested persons to read important scientific articles and subscribe scientific journals. Indeed, the research articles span a wide range of area and of high quality. This is specially a must for researchers belonging to institutions with limited library facility and funding to subscribe scientific journals."


Debomoy K. Lahiri
(Indiana University School of Medicine, USA)

"Open access journals represent a major break-through in publishing. They provide easy access to the latest research on a wide variety of issues. Relevant and timely articles are made available in a fraction of the time taken by more conventional publishers. Articles are of uniformly high quality and written by the world's leading authorities."


Robert Looney
(Naval Postgraduate School, USA)

"Open access journals have transformed the way scientific data is published and disseminated: particularly, whilst ensuring a high quality standard and transparency in the editorial process, they have increased the access to the scientific literature by those researchers that have limited library support or that are working on small budgets."


Richard Reithinger
(Westat, USA)

"Not only do open access journals greatly improve the access to high quality information for scientists in the developing world, it also provides extra exposure for our papers."


J. Ferwerda
(University of Oxford, UK)

"Open Access 'Chemistry' Journals allow the dissemination of knowledge at your finger tips without paying for the scientific content."


Sean L. Kitson
(Almac Sciences, Northern Ireland)

"In principle, all scientific journals should have open access, as should be science itself. Open access journals are very helpful for students, researchers and the general public including people from institutions which do not have library or cannot afford to subscribe scientific journals. The articles are high standard and cover a wide area."


Hubert Wolterbeek
(Delft University of Technology, The Netherlands)

"The widest possible diffusion of information is critical for the advancement of science. In this perspective, open access journals are instrumental in fostering researches and achievements."


Alessandro Laviano
(Sapienza - University of Rome, Italy)

"Open access journals are very useful for all scientists as they can have quick information in the different fields of science."


Philippe Hernigou
(Paris University, France)

"There are many scientists who can not afford the rather expensive subscriptions to scientific journals. Open access journals offer a good alternative for free access to good quality scientific information."


Fidel Toldrá
(Instituto de Agroquimica y Tecnologia de Alimentos, Spain)

"Open access journals have become a fundamental tool for students, researchers, patients and the general public. Many people from institutions which do not have library or cannot afford to subscribe scientific journals benefit of them on a daily basis. The articles are among the best and cover most scientific areas."


M. Bendandi
(University Clinic of Navarre, Spain)

"These journals provide researchers with a platform for rapid, open access scientific communication. The articles are of high quality and broad scope."


Peter Chiba
(University of Vienna, Austria)

"Open access journals are probably one of the most important contributions to promote and diffuse science worldwide."


Jaime Sampaio
(University of Trás-os-Montes e Alto Douro, Portugal)

"Open access journals make up a new and rather revolutionary way to scientific publication. This option opens several quite interesting possibilities to disseminate openly and freely new knowledge and even to facilitate interpersonal communication among scientists."


Eduardo A. Castro
(INIFTA, Argentina)

"Open access journals are freely available online throughout the world, for you to read, download, copy, distribute, and use. The articles published in the open access journals are high quality and cover a wide range of fields."


Kenji Hashimoto
(Chiba University, Japan)

"Open Access journals offer an innovative and efficient way of publication for academics and professionals in a wide range of disciplines. The papers published are of high quality after rigorous peer review and they are Indexed in: major international databases. I read Open Access journals to keep abreast of the recent development in my field of study."


Daniel Shek
(Chinese University of Hong Kong, Hong Kong)

"It is a modern trend for publishers to establish open access journals. Researchers, faculty members, and students will be greatly benefited by the new journals of Bentham Science Publishers Ltd. in this category."


Jih Ru Hwu
(National Central University, Taiwan)


Browse Contents



Webmaster Contact: info@benthamopen.net
Copyright © 2019 Bentham Open