铺置方式对组合粒径石英砂支撑剂裂缝导流能力的影响

Effect of Placement Modes on Fracture Conductivity of Combined-Size Quartz Sand Proppants

摘要: 为明确不同铺置方式对组合支撑剂裂缝导流能力的影响，选取20/40目 + 30/50目、30/50目 + 40/70目和40/70目 + 70/140目3种石英砂组合，分别采用尾追式铺置与混合式铺置，在不同闭合压力条件下开展短期导流能力实验。结果表明，3种组合支撑剂的导流能力均随闭合压力升高而降低。20/40目 + 30/50目和40/70目 + 70/140目组合在混合式铺置条件下表现出较高的导流能力，且在高闭合压力下优势更明显；30/50目 + 40/70目组合的导流能力则呈现阶段性反应，不同闭合压力条件下两种铺置方式的导流能力存在差异。研究表明，组合支撑剂导流能力受粒径组合、铺置结构及闭合压力共同控制，其变化与颗粒堆积形成的孔隙结构及充填层承载稳定性相关。

Abstract: To clarify the effects of different proppant placement modes on fracture conductivity, three quartz sand combinations, namely 20/40 + 30/50 mesh, 30/50 + 40/70 mesh, and 40/70 + 70/140 mesh, were investigated. Short-term conductivity tests were conducted under different closure pressures using tail-in placement and mixed placement. The results show that the fracture conductivity of all three proppant combinations decreased with increasing closure pressure. For the 20/40 + 30/50 mesh and 40/70 + 70/140 mesh combinations, mixed placement yielded higher fracture conductivity than tail-in placement, with the advantage becoming more pronounced at high closure pressures. In contrast, the 30/50 + 40/70 mesh combination exhibited a stage-dependent response, with the relative conductivity performance of the two placement modes varying with closure pressure. The results indicate that the conductivity of combined proppants is jointly governed by particle-size combination, placement structure, and closure pressure, and is closely associated with the pore structure formed by particle packing and the load-bearing stability of the proppant pack.