J. Cent. South Univ. Technol. (2008) 15(s1): 176-180

DOI: 10.1007/s11771-008-341-z

Rheological properties of novel viscoelastic micelle systems containing anionic-nonionic dimeric surfactant

FANG Bo(方 波), CAO Dan-hong(曹丹红), JIANG Ti-qian(江体乾)

(School of Chemical Engineerring, East China University of Science and Technology,Shanghai 200237, China)

Abstract: The viscoelastic micelle systems formed by novel anionic-nonionic dimeric surfactant and conventional cationic surfactant cetyltrimethylammonium(1631) were studied. The viscoelasticity, thixotropy, flow curves and constitutive equation for the novel viscoelastic micelle systems were investigated. The results show that the micelle systems possess viscoelasticity, thixotropy, and shear thinning property. Some micelle systems possess hysteresis loops showing both viscoelasticity and thixotropy. It is proved that the flow curves are characterized by the co-rotational Jeffreys constitutive equation correctly.

Key words: dimeric surfactant; viscoelastic micelle; clean fracturing fluid; constitutive equation

1 Introduction

Hydraulic fracturing treatment is an important technology to stimulate the reservoir with low permeability and to improve the well productivity. The clear viscoelastic micelle fracturing fluid is a novel kind of fracturing fluids with great promise in application^[1-3]. Gemini becomes a new generation surfactant because of its special structure and the higher surface activity than the conventional surfactant^[4-7]. Viscoelastic surfactant system is the important basis of the clear micelle fracturing fluid. In this work, the viscoelastic micelles consisting of novel anionic-nonionic dimeric surfactant were studied. The rheological properties for the novel viscoelastic micelle were investigated. The flow curves of the novel viscoelastic micelle systems were described by co-rotational Jeffreys model.

2 Experimental

The novel anionic-nonionic dimeric surfactant was prepared according to Ref.[8].

The viscoelastic micelle fracturing fluids were prepared by mixing novel anionic-nonionic dimeric surfactant and cetyltrimethylammonium (1631) in proper concentration. The components of the typical viscoelastic micelle systems studied are summarized in Table 1.

The rheological properties including viscoelasticiy, hysteresis loops and flow curves for the viscoelastic micelle systems were measured by rheometer (Type ARES).

3 Results and discussion

3.1 Viscoelasticity of novel micelle systems

The viscoelastic indexes for the typical viscoelastic micelle systems containing novel anionic-nonionic dimeric surfactant at 25 ℃ are shown in Fig.1.

From Fig.1, it is obvious that these typical micelle systems containing novel anionic-nonionic dimeric surfactant possess elasticity significantly.

3.2 Thixotropy of viscoelastic micelle systems contain- ing novel anionic-nonionic dimeric surfactant

The shear rate changes with time in a triangular step. It ascends from 0 to 200 s^-1 within 60 s, and then descends from 200 to 0 within 60 s. The hysteresis loops for the systems are obtained and shown in Fig.2.

From Fig.2, it can be seen that, the hysteresis loops for systems are different due to different compositions. System 1 and System 6 just exhibit thixotropy. System 3 exhibits small thixotropic and viscoelastic hysteresis loops, indicating that it behaves with weak viscoelasticity and thixotropy. System 2, System 4 and System 5 exhibit complex “8”-form hysteresis loops, indicating that theses systems possess both viscoelasticity and thixotropy simultaneously. The results show that, the effects of the contents of novel anionic- nonionic dimeric surfactant and 1631, the sorts and concentration of salt on the viscoelasticity and thixotropy of the micelle systems are significant.

Table 1 Components of typical viscoelastic micelle systems containing novel anionic-nonionic dimeric surfactant (mass fraction, %)

Fig.1 Viscoelasticity of micelle systems: (a) System 1; (b) System 2; (c) System 3; (d) System 4; (e) System 5; (f) System 6

Fig.2 Hysteresis loops of viscoelastic micelle systems containing novel anionic-nonionic dimeric surfactant at 25 ℃: (a) System 1; (b) System 2; (c) System 3; (d) System 4; (e) System 5; (f) System 6

3.3 Characterization of novel viscoelastic micelle systems

In order to understand the constitutive equation for novel viscoelastic micelle systems containing novel anionic-nonionic dimeric surfactant, the non-linear co-rotational Jeffreys constitutive equation was applied to describing the flow curves. The relationship between viscosity and shear rate predicted by the non-linear co-rotational Jeffreys constitutive equation is

                         (1)

The results are shown in Fig.3, and the model parameters for the flow curves are listed in Table 2.

From Fig.3, it is evident that the calculated values are in good agreement with the experimental data.

Fig.3 Characterization of flow curves for systems by co-rotational Jeffreys model under 25 ℃: (a) System 1; (b) System 2; (c) System 3; (d) System 4; (e) System 5; (f) System 6

Table 2 Parameters for flow curves described by co-rotational Jeffreys constitutive equation

Therefore, the non-linear co-rotational Jeffreys constitutive equation is proved to describe the flow curves of the viscoelastic micelle systems consisting of novel anionic-nonionic dimeric surfactant.

4 Conclusions

1) The novel viscoelastic micelle systems consisting of anionic-nonionic dimeric surfactant possess good viscoelasticity and shear thinning properties.

2) The hysteresis loops prove that the some micelle systems exhibit both thixotropy and viscoelasticity simultanously.

3) The co-rotational Jeffreys constitutive equation may be applied to characterizing the flow curves for the novel viscoelastic micelle systems consisting of anionic- nonionic dimeric surfactant. The calculated values are in good agreement with the experimental data and the parameters are reasonable.

References

[1] MANILAL S D, JIANG Y. Viscoelastic surfactant fluids and related methods of use. US 0054962A1 [P]. 2003.

[2] ZHOU J, HUGHES T. Viscoelastic compositions. WO 02/064945 A1 [P]. 2002.

[3] HUGHES T, JONES T, GARETH J, et al. Aqueous viscoelastic fluid. WO 02/064947 A1 [P]. 2002.

[4] ROSEN M J. Gemini surfactants—properties of surfactant molecules with two hydrophilic groups and two hydrophobic groups [J]. Cosmetics & Toiletries, 1998, 113: 49-55.

[5] ZANA R. Dimeric and oligomeric surfactants behavior at interfaces and in aqueous solution: A review [J]. Advances Colloid and Interface Science, 2002, 97(1/3): 205-253.

[6] MENGER F M，KEIPER J S. Gemini surfactants [J]. Angew Chem lnt Ed, 2000, 39: 1906-1920.

[7] ROSEN M J. Geminis: A new generation of surfactants [J]. Chemtech, 1993, 23(3): 30-33.

[8] CAO Dan-hong. Study on the microemulsion and micelle of novel oligomeric nonionic surfactants [D]. Shanghai: East China University of Science and Technology, 2006. (in Chinese)

(Edited by YANG Bing)

Foundation item: Project(20276016) supported by the National Natural Science Foundation of China

Received date: 2008-06-25; Accepted date: 2008-08-05

Corresponding author: FANG Bo, Professor, PhD; Tel: +86-21-64253361; E-mail: fangbo@ecust.edu.cn