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支撑剂嵌入煤层会损害压裂支撑裂缝导流能力。目前关于煤岩支撑剂嵌入的研究主要为实验研究,缺乏相应的理论数值计算模型。为此,对沁水盆地端氏、曲堤和候村高阶煤层的支撑剂进行嵌入实验,分析了闭合压力和煤岩坚固性系数对支撑剂嵌入的影响;根据Langmuir定律,推导出二维多层支撑剂嵌入煤岩的缝宽模型和压嵌模型,利用实验数据对模型进行了验证。结果表明:支撑剂嵌入煤岩时,存在临界嵌入压力,煤岩坚固性系数越小,临界嵌入压力越小,支撑剂越易嵌入煤岩;在闭合压力小于30 MPa时,支撑剂嵌入煤岩程度小于支撑剂粒径的1/2时,模型计算结果与实验测试结果相似程度较高,推导出的缝宽模型和压嵌模型能有效指导沁水盆地高阶煤层的水力压裂施工设计。
The proppant imbedded in the coal seam can damage the fissure support fracture conductivity. At present, the research on the embedding of coal and rock proppant is mainly based on experimental research, and there is no corresponding theoretical numerical calculation model. For this reason, proppant experiments were carried out on the proppants of Duan, Qudi and Houmu high-rank coal seams in Qinshui Basin. The influence of closure pressure and coal-rock solidity coefficient on proppant embedding was analyzed. According to Langmuir’s law, The multi-layer proppant is embedded in the coal seam rock width model and the pressure inlay model, and the experimental data are used to verify the model. The results show that when the proppant is embedded in coal, there is a critical embedding pressure. The smaller the rigidity coefficient of coal and the lower the critical embed pressure, the easier the proppant is embedded in the coal. When the closing pressure is less than 30 MPa, the proppant is embedded in the coal and rock When the degree of proppant diameter is less than 1/2 of the proppant particle size, the calculated results of the model are similar to those of the experimental test results. The proposed slot width model and inlay model can effectively guide the hydraulic fracturing design of high-rank coal seams in Qinshui Basin.