沁端区块煤层气井压裂支撑剂优选实验研究

根据沁端区块煤储层特点,进行支撑剂优选研究和煤层气井压裂裂缝导流能力实验研究,对比分析了在不同闭合压力下铺砂质量浓度、支撑剂粒径、支撑剂粒径组合、支撑剂嵌入等因素对煤岩层导流能力的影响,优选出了煤层压裂改造用支撑剂体系。研究结果表明,支撑剂充填层导流能力随闭合压力的增加而降低,支撑剂粒径越大其导流能力越高,在压裂施工条件允许情况下应尽量多使用大粒径的支撑剂;沁端区块宜采用20/40目和16/20目兰州石英砂作为压裂用支撑剂,并确定了体积比为4∶1的支撑剂粒径组合方式;加大铺砂质量浓度能够在一定程度上提高裂缝的导流能力,降低支撑剂嵌入对导流能力的影响。

Experimental Research of Proppant Optimization in CBM Wells of Qinduan Block

According to the characteristics of coal reservoir in Qinduan block, the experimental research on proppant optimization and fracture conductivity were conducted. The experiment contrastively analyzed the factors such as sand mass concentration, proppant particle size, proppant particle size combination, proppant embedment, and their effects on conductivity of fracturing under the condition of various closure pressures. Fracturing proppant system was optimized through experimental study. The results show that the conductivity of proppant pack decreased along with the increasing of closure pressures, so if the fracturing conditions was permitted, we should use large diameter proppant as much as possible; Qinduan block should adopt the 20/40 mesh and 16/20 mesh Lanzhou silica sand as fracturing proppant, and when the ratio was 4 ： 1, the combination is appropriate; increasing sand mass concentration can increase fracture conductivity to some extent and reduce the impact of proppant embedment on the conductivity .