煤储层压裂轻质陶粒支撑剂粒级配比优化

Hydraulic fracturing is currently one of the main technical measures for reservoir stimulation and permeability enhancement of coal seams. The placement range and transportation distance of proppants in the fracturing fractures are important indicators for measuring the effect of hydraulic fracturing. According to the characteristics of coal reservoirs in the Lu'an mining area, physical experiments and numerical simulation methods were used to comparatively analyze the influence of factors such as the conductivity of fracturing proppants, the sand placement range, and the particle size combination in the test coalbed methane wells on the fracture conductivity, and the optimal proppant particle size and particle size ratio were screened out. The results show that with the increase of closure pressure, the fracture conductivity of coated lightweight ceramsite proppants with different particle sizes decreases; the length of the sand bank and sand placement area formed by the same particle size coated lightweight ceramsite in the fracture is about twice that of traditional quartz sand; among the three particle sizes of coated lightweight ceramsite, 40 - 60 mesh (0.25 - 0.38 mm), 16 - 40 mesh (0.38 - 1.00 mm), and 12 - 20 mesh (0.83 - 1.40 mm), the 12 - 20 mesh has the shortest fracturing fracture length, the shortest propped fracture length, and the lowest average proppant concentration, but the highest conductivity; when the ratio of the three particle sizes of 40 - 60 mesh, 16 - 40 mesh, and 12 - 20 mesh is 1∶6∶2, the fracturing effect of the coated lightweight ceramsite is the best, with an average fracture length of 320 m, a fracture width of 0.672 cm, a proppant density of 5.16 kg/m~2, and a fracture conductivity of 1.263. When using coated lightweight ceramsite proppants for fracturing in coalbed methane wells in the Lu'an mining area, by optimizing the proppant particle size ratio, the fracture conductivity can be significantly improved to enhance the permeability of coal reservoirs and the coalbed methane production effect.

水力压裂是目前煤储层改造增透的主要技术措施之一,支撑剂在压裂裂缝中的铺置范围和输送距离是衡量水力压裂效果的重要指标。针对潞安矿区煤储层特点,采用物理实验和数值模拟方法,对比分析试验煤层气井压裂支撑剂导流能力、铺砂范围、粒径组合等因素对裂缝导流能力的影响,筛选出最优的支撑剂粒径和粒级配比。结果表明,随着闭合压力增大,不同粒径覆膜轻质陶粒支撑剂对裂缝导流能力降低;相同粒径覆膜轻质陶粒在裂缝中形成的砂堤和铺砂区长度是传统石英砂的2倍左右;40~60目(0.25~0.38 mm)、16~40目(0.38~1.00 mm)、12~20目(0.83~1.40 mm)3种粒级覆膜轻质陶粒中,12~20目压裂裂缝长度、支撑缝长和平均支撑剂浓度最小,而导流能力最高;当3种粒级40~60目、16~40目、12~20目配比为1∶6∶2时,覆膜轻质陶粒压裂效果最好,平均裂缝缝长320 m,裂缝宽度0.672 cm,支撑剂密度5.16 kg/m~2,裂缝导流能力为1.263。潞安矿区煤层气井采用覆膜轻质陶粒支撑剂压裂时,通过优化支撑剂粒度配比,显著提高裂缝导流能力,以提高煤储层渗透性和煤层气开采效果。