Four ionic liquids were screened using the UNIFAC model in Aspen Plus. At infinite dilution, their selectivities for aromatic/non⁃aromatic mixtures were evaluated, and 1⁃ethyl⁃3⁃methylimidazolium methanesulfonate ([EMIM][MESO3]) was selected as the extractant. A sulfolane⁃based aromatic extraction model and an [EMIM][MESO3]⁃based aromatic extraction model were then established. Sensitivity analysis and orthogonal experiment were used to optimize the process parameters of the two models and determine the optimal operating conditions. The results show that the [EMIM][MESO3]⁃based extraction process provides better separation performance than the sulfolane⁃based process. In terms of energy consumption and economics, compared with the sulfolane⁃based process, the [EMIM][MESO₃]⁃based process reduces cooler and heater energy consumption by 69.58% and 46.38%, respectively. The annual total investment (ΔTIC), annual operating cost (TOC), and annual total cost (ΔTAC) are reduced by 30.15%, 30.08%, and 30.13%, respectively.

Shale hydration and dispersion lead to instability of the borehole wall, which has always been a problem in oil and gas drilling engineering. Physically plugging pores and micro?cracks in shale through nano plugging agents is the best way to improve the stability of shale formations. In this work, the silane coupling agent KH560 was used to modify the high?concentration silica sol. The principle of soap?free emulsion polymerization was used in combination with solvothermal synthesis to graft acrylic acid (AA) and styrene (St) monomers on the surface of modified SiO₂ particles. Thus, a new type of elastic pressure?bearing plugging agent with polymer?encapsulated nanoparticles was successfully developed. Taking medium pressure filter loss as the evaluation index, the best synthesis conditions were obtained: The reaction temperature was 60 ℃, the reaction time was 3.0 h, the monomer ratio was 3∶2, the pre?emulsification time was 10.0 min, the total monomer mass was 6.67%, and the amount of initiator was 0.40%. In addition, Zeta potential, particle size analyzer and transmission electron microscope proved that the median particle size of the prepared STA?1 plugging agent was 45.3 nm. Finally, a core displacement experiment was used to simulate the shale layer to investigate the actual plugging effect of STA?1. The results revealed that 1.00% STA?1 showed good water plugging ability for sand filled pipes with permeability below 2 000 mD, and the plugging rate was higher than 85%.