煤岩不同类型支撑剂嵌入实验研究

Experimental Research on Different Types of Proppant Embedding in Coal Rock

针对3种支撑剂在不同闭合压力下的嵌入规律进行了实验研究。结果表明:支撑剂停止嵌入时间与闭合压力大小有关。在2~4 MPa时,3种支撑剂嵌入深度相同;在4~9 MPa时,覆膜砂嵌入深度最大,石英砂次之,陶粒最小;在9~18 MPa时,覆膜砂嵌入深度依然最大,陶粒的嵌入深度则大于石英砂。不同闭合压力下,支撑剂嵌入岩心表面破碎情况经历"弹性变形-微破裂-局部破裂-破裂面连通"4个阶段。压裂设计时,可根据实验研究结果,结合实际地应力梯度对支撑剂进行优选。

The experimental study of the embedding law of three kinds of proppant under different closed pressures is carried out. The results show that the stopping time of the proppant is related to the size of the closed pressure. At 2 to 4 MPa, the embedded depth of the three kinds of support agents is the same; at 4 to 9 MPa, coated sand embedded deepest, quartz sand is the second, ceramsite is the minimum; at 9 to 18 MPa, coated sand embedded depth is still the largest, the embedded depth of ceramsite is larger than quartz sand. Under the different closure pressures, the proppant embedded cause to core surface breaking experience 'elastic deformation-micro rupture-partial rupture-rupture plane connected' four stages. When fracturing design, according to the experimental results, combined with the actual in-situ stress gradient to optimize the proppant.