Development of oxazolidines derived from polyisobutylene succinimides as multifunctional stabilizers of asphaltenes in oil industry

The aim of the research presented herein was to develop novel multifunctional stabilizers of asphaltenes (Asph) for the control of fouling in different stages of petroleum industry. Novel stabilizers were obtained from the reaction between polyisobutenyl succinic anhydride (PIBSA), 2-(2-aminoethylamino)ethanol (AEAE) and an R-substituted aldehyde, resulting in three 2-R-(polyisobutylenesuccinimidyl)oxazolidines as prototypes of multifunctional Asph stabilizers, where R is –H (P1), –C₅H₁₁ (P2) or –ortho(OH)C₆H₄ (P3). Compounds P1-3 were characterized by FTIR, ¹H, ¹³C and 2D NMR spectroscopies, and assessed in four different types of evaluations: (i) Asph dispersion by UV–vis, (ii) displacement of Asph onset precipitation, at ambient conditions, (iii) inhibition of electric field induced deposition of Asph, and (iv) displacement of Asph onset precipitation, at reservoir conditions. All the latter individual efficiencies were included in a multifunctional development factor (MDF) resulted in 0.626 for P1, 0.326 for P2, and 0.679 for P3, where the higher value corresponded to the highest efficiency. For comparison purposes, two commercial stabilizers of Asph were also evaluated, resulting in MDF of 0.012 and 0.162, being P1-3 clearly better multifunctional chemicals. Best novel prototype was selected for industrial evaluation by taking into account technical and economic criteria, thus P1 compound was chosen as active component of DAIM chemical and was successfully assessed at industrial scale in a production well of Petróleos Mexicanos (PEMEX) to control Asph fouling. The continuous injection of DAIM produced important benefits to the oil well productivity, such as the decrease of the frequency of cleaning operations from 11 to 4 in a one-year evaluation period and the reduction of production rate decay from −1.48 to −0.032m³/day, ca. 46times less in comparison when the well was operated without Asph stabilizer.