Nutshell filter material is made of high-quality hickory as raw material, which is processed through crushing, polishing, steam washing and drug treatment, and two screening processes. The filter material has high hardness, wear resistance and good pressure resistance. The pressure resistance is 23.4KgF, the chemical performance is stable, it does not dissolve in acids and alkalis, the adsorption and interception ability is strong, the adsorption rate is 27-50%, and the hydrophilicity is good. Oil immersion, specific gravity g / cm31.25, slightly larger than water, filling specific gravity 0.85g / cm3, easy to backwash and regenerate, compared with other filter materials, its advantage is that it directly uses water backwash before filtering, and low operating cost. The backwashing intensity is low (6.71 / S. M2), and the filtering speed is fast (24-26 / n). The filter material does not agglomerate, does not rot, is easy to regenerate and does not replace. It only needs to add 5-10% every year. It has a significant effect on the treatment of oil-field-containing water. The oil removal is up to 95%, and the oil content drops below 5mg / l.