Preparation of Multifunctional Surfactants Derived from Sodium Dodecylbenzene Sulfonate and Their Use in Oil-Field Chemistry

Four products were obtained from sodium dodecylbenzene sulfonate (SDBS) and formaldehyde (40% solution) using a simple reaction. The products were characterized by TGA, IR, UV and MS to confirm the major chemicals in each sample. The new products could reduce the interfacial tension between oil and water in the experimental temperature range further compared to SDBS. The emulsion ability was also enhanced by SDBS-1 to SDBS-4. The oil-displacement efficiencies of SDBS-1 to SDBS-4 were obviously higher than that of SDBS, and the oil-displacement efficiency of SDBS-2 was the best, with an efficiency of 25%. The experimental results all indicate that these products have an excellent ability to reduce oil-water interfacial tension and that they can be used in the oil and petrochemical industry for oil production and have certain practical uses.

Influence of series of long-chain cationic surfactants on the quality characteristics of nano silica induced zinc phosphated mild steel

Mild steel panels were zinc phosphated employing environmentally safe nano silica as an accelerator and a series of four cationic surfactants as additives. The four cationic surfactants chosen were decyltriethyl ammonium bromide (C10TEAB), dodecyltriethyl ammonium bromide (C12TEAB), hexadecyltriethyl ammonium bromide (C16TEAB), and octadecyltriethyl ammonium bromide (C18TEAB). The length of the alkyl chain of the surfactant compounds influenced the quality of the coatings. The corrosion resistance of the coated panels was assessed using a salt spray test. The hydrophobicity of the coatings increased as the hydrocarbon chain length of the surfactants extended from C10 to C18. Porosity, adhesion, and roughness tests were used to examine the surface properties of the coated panels. The coating weight and thickness of the resultant coatings on the base metal were used to quantify coating quality. The results of the tests revealed that the presence of C16TEAB additive outperformed all other components in terms of coating efficiency, coating thickness, and corrosion inhibition performance. The optimal quantity of C18TEAB deposited had a maximum coating weight of 0.0430 g/mm2 that enhanced durability, appearance, and barrier qualities.

Study of a high efficient composite foam drainage surfactant for gas production

The foam drainage technique for gas production has the disadvantage of requiring a large amount of surfactant and having low resistance to salt and oil. In this study, a new surfactant mixture (composite surfactant) of lauramidopropyl betaine (LAB-35), α-olefin sulfonate (AOST), sodium alkyl sulfonate (SASE) and cetyltrimethylammonium bromide (CTAB) was tested and its foaming properties were investigated in detail. The foaming properties were determined using high-speed measurements and the Ross-Miles method. The results show that the foaming volume of the composite surfactant can reach 563 mL, indicating that the foaming behaviour of the composite surfactant is more effective than that of the individual surfactants used for the mixture. In addition, the results show that the composite surfactant has a resistance to salt, methanol and condensate oil that most foam drainage agents do not have. However, the stability of the composite surfactant gradually decreases with increasing temperature and concentration. The surface tension was measured and the critical micelle concentration of the composite surfactant is 0.023 g/L.

Use of Betaine-Based Gel and Its Potential Application in Enhanced Oil Recovery

In this paper, a betaine-based gel containing 2.0% erucamide propyl betaine (EAPB), 0.5% oleic acid amide propyl betaine (OAPB), and 0.1% KCl was prepared for use as a fracturing fluid. The performance evaluation showed that KCl may improve the temperature resistance and increase the viscosity of the optimized fracturing fluid. At 80 °C, the apparent viscosity of the viscoelastic surfactant (VES)-based fracturing fluid was approximately 50 mPa·s. Furthermore, the gel had high shear resistance, good viscosity stability, and high sand-carrying performance. After being sheared at 170 s−1 for 60 min, the reduction in viscosity was 13.6%. The viscosity of the gel was relatively stable at room temperature (27 °C) for one week. In a suspension containing 10% sand (particle size < 0.45 mm, density = 2.75 g cm−3), the settling velocity of proppant particles was 1.15 cm h−1. In addition, we detected that the critical micelle concentration of this gel was approximately 0.042 wt%. The viscosity could be reduced to <5 mPa·s at 60 °C within 1 h when 6.0% crude oil was present, and oil displacement experiments showed that the broken fracturing fluid can enhance the oil displacement rate up to 14.5%. This work may facilitate research on fracturing fluids and oil recovery.

Corrosion Inhibition Coating Based on the Self-Assembled Polydopamine Films and Its Anti-Corrosion Properties

Metal corrosion is becoming increasingly serious in oil and gas production, and one way to solve this problem is to modify the metal surface. Thus, a corrosion inhibition coating on the N80 steel was constructed via the self-polymerization and assembling of the dopamine. The optimum reaction condition of polydopamine films was determined by the corrosion rate assessment of the films coated N80 steel, which was the reaction at 60 °C and 5 g/L dopamine in the Tris-HCl buffer solution (pH = 8.5) for 1 h. The spectral results confirmed the existence of the polydopamine coating on the surface of N80 steel, and high stability of the coating in the oil well produced water was observed. The anti-corrosion performance of the polydopamine-coated N80 steel confirmed that high temperature accelerated the anti-corrosion effect of the coating, and the corrosion rate of N80 plate in 90 °C oil well produced water was 0.0591 mm·a⁻¹, lower than the standard value. The corrosion rates of the polydopamine coated N80, A3 and J55 plates at 90 °C were 0.0541 mm·a⁻¹, 0.0498 mm·a⁻¹ and 0.0455 mm·a⁻¹, respectively. No significant effects of the categories of corrosive medium and steel plate on the performance of the coating were observed.

Research of a Surfactant Gel with Potential Application in Oilfield

In this study, a viscoelastic surfactant gel was composed using erucoylamine propyl betaine and other additives. The formulation of this viscoelastic surfactant gel solution was determined as: erucamide propyl betaine:oleic acid amide propyl betaine:octadecyl hydroxyl sulfonate betaine = 1.7%:1.36%:0.01%. Then the performance of viscoelastic surfactant gel fluid was evaluated. The results showed that the viscoelastic surfactant gel has good temperature resistance and salt resistance. At 50°C, the apparent viscosity reaches the maximum value, 37 mPa · s, and it displays high shear resistance under the shear rate of 170 s–1, with the viscosity retention of 83.3%. Kerosene (1%) can completely break the gel within 2 h, which can convert the gel into a surfactant solution soon. Also the gel shows high emulsion ability, which can benefit the oil displacement in oilfield. Finally this gel can enhance the oil displacement rate as high as 28%.