At present

the clean quartz sand is used in the fracturing of southern Yanchuan CBM wells. According to the production effect in the early stage

the limited length of supporting seam generated by the clean quartz sand fracturing leads to the difficulty of adding sand in the construction

and the gas production effect in the later stage is not ideal. In order to solve this problem

laboratory experiments have been conducted to compare and evaluate the crushing and fracture conductivity of conventional quartz sand proppant and low-density nut shell proppant under different closing pressures. The experimental results show that the fracturing rates of both can meet the engineering requirements. Under high closure stress（35 MPa）

they have similar fracture conductivity. However

low-density nut shell proppant is cheaper than traditional quartz sand. Therefore

low-density nut shell proppant is more able to meet the current goal of cost reduction and production increase. The field test of this technology has obtained good results.