Effect and optimization of anionic and cationic surfactants on the performance of self-diverting acids in coal

Aiming at the serious problem of dust pollution in coal mines, the OAPB automatic diverting acid solution of coal seams was studied to uniformly distribute acid, so as to improve the water content of coal bodies. In order to achieve better results in coal mines, this paper studied the effects of different anionic and cationic surfactants on the viscosity and wettability of self-diverting acid using methods such as viscosity, chargeability, and functional groups, explored the internal causes of performance changes, and optimized based on the test results. The results show that cationic surfactants can directly cause gel breaking of self-diverting acid, and the addition of anionic surfactants can increase the viscosity of self-diverting acid. SSA/SDBS has good wettability, with a minimum surface tension of 24.12 mN/m; SSA/SDBS-16 has an overall higher surface tension value, poor self-wetting performance, and weaker adsorption performance on the coal bodies. Through infrared experiments, it was found that OAPB molecules tended to form hydrogen bonds under the action of SSA/SDBS, and the percolation effect of self-diverting acid solution was verified through triaxial percolation experiments.