Study Of The Effect Of Additional Solution On The Coal Surface Structure

As a kind of the most realistic air supply in recent years, coalbed methane has hugedevelopment potential. At present, fracturing technology is commonly adopted for coalbedmethane exploitation, the key of which is the fracturing liquid development. Most of thecoalbed methane in China belongs to low permeable reservoirs, and it is difficult to exploit. Itis difficult to make up once is damaged. Therefore, Property of additives is important for theresearch on minimizing damages of fracturing liquid on stratum. In this paper, step-by-stepsolvent extraction and adsorption experiments on the coal immersed by ionic liquid areconducted to research the change of coal surface structure before and after immersion, and todiscuss the effect of additional ion on coal surface structure. Accordingly, it can provide withbeneficial reference for exploitation of new kinds of low-damage fracturing liquidIn this paper, CTAB, CAB, SDBS, TX-10, SFA and SFB are chosen to immerse Baode,Hancheng and Jincheng coal to prepare coal residue, then step-by-step sohxlet extraction oncoal residue are conducted. GC-MS analysis is conducted to analyze extractant of the raw coaland immersed coal. Results indicates that effect of anionic surfactant SDBS and zwitterionicsurfactant CAB on low molecular compound in Baode coal, Hancheng Coal and Jinchengcoal is significant; The longer of immersion time, the larger of the effect of additional liquidon low molecular compound in coal. Additional liquid immersion mainly influence the CH2,C=O and alkyl side chain; the higher of coal rank, the less of effect on coal.In this paper, ultraviolet spectrophotometry is chosen to study the adsorptive property ofcoal on additional liquid. Results demonstrate that the higher of coal rank, the larger ofadsorbing capacity on additional liquid, and the lager of the adsorbing rate; adsorption processis jointly controlled by film diffusion and diffusion in the particle.