Preparation and Evaluation of Modified Ethylene–Vinyl Acetate Copolymer as Pour Point Depressant and Flow Improver for Jianghan Crude Oil

Abstract

The ethylene–vinyl acetate copolymer (EVA) was modified by alkali-catalyzed alcoholysis. The alcoholized EVA (EVAL) was characterized by Fourier transform infrared (FTIR) spectroscopy and 1H nuclear magnetic resonance (1H NMR). Moreover, the influence of modified polar groups of EVA on the crystallization process of wax was investigated through differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The results showed that EVAL had better performance than EVA in reducing the pour point and the viscosity of crude oil. EVAL could change the wax crystal habit and obviously lower the wax precipitation amount of crude oil. In addition, EVAL with stronger polarity could provide greater electrostatic repulsion force to wax crystals compared with EVA, which made the wax crystals have more difficulty to connect together and form a much looser network structure.

Synthesis and Evaluation of Grafted EVAL as Pour Point Depressant for Waxy Crude Oil

“…But for crude oil treated with EVAL (see Figure 10b2), the network structure was much looser at its pour point temperature (36 °C), which was in accordance with our previous studies. 10 However, as given in Figure 10b3, relatively few wax crystals appeared at 36 °C in crude oil treated with EVAL-g-16, which further proved that EVAL-g-16 could improve wax solubility and change the wax crystallization process. From this point of view, it was one of the reason that EVAL-g-16 could reduce the pour point of crude oil to a great extent.…”

“…The alcoholized ethylene-vinyl acetate copolymer (EVAL) with alcoholysis degree of 90.94 mol % was obtained from our previous studies. 10 The Shengli (SL) and Jianghan (JH) crude oils were provided by SL and JH oil fields of China, respectively. Before testing, the crude oil samples were first heated to 90 °C for 4 h to eliminate the thermal and shearing history.…”

“…All samples were preheated to 90 °C for 5 min, and then cooled to the test temperature with a cooling rate of 5 °C/min and equilibrated for 5 min. 10 Each micrograph was investigated in duplicate to guarantee the reproducibility. 34 3.…”

“…Previous studies 10 revealed that alcoholized ethylene−vinyl acetate copolymer (EVAL) was more efficient than EVA to promote the flowability of crude oil. In this work, EVAL was further modified by grafting n-alkyl acrylates with different alkyl chain lengths.…”

Study the rheological properties of waxy oil with modified pour point depressants for the South Turgai oil field in Kazakhstan

“…Researchers studied the EVA copolymers as PPD and flow improver for many crude waxy oils [10][11][12][13]. In order to further increase the effectiveness of EVA copolymers, some researchers modified EVA copolymer with alcohols and grafted polymers [14,15] In this research, we modified EVA copolymer with alkali-catalyzed alcoholysis and copolymer hydrolysis degree of 5 mol.% obtained and characterized. The obtained modified EVA copolymer tested in five different crude oils with various wax content.…”