李浩哲, 姜在炳, 孙四清, 朱传勇, 范耀, 郭勇, 程斌. 井地联合压裂长输管路支撑剂悬浮运移规律模拟研究[J]. 煤田地质与勘探.
引用本文: 李浩哲, 姜在炳, 孙四清, 朱传勇, 范耀, 郭勇, 程斌. 井地联合压裂长输管路支撑剂悬浮运移规律模拟研究[J]. 煤田地质与勘探.
LI Haozhe, JIANG Zaibing, SUN Siqing, ZHU Chuanyong, FAN Yao, GUO Yong, CHENG Bin. Study on suspension and migration law of proppant in long-distance pipeline for ground-coalmine combined hydraulic fracturing[J]. COAL GEOLOGY & EXPLORATION.
Citation: LI Haozhe, JIANG Zaibing, SUN Siqing, ZHU Chuanyong, FAN Yao, GUO Yong, CHENG Bin. Study on suspension and migration law of proppant in long-distance pipeline for ground-coalmine combined hydraulic fracturing[J]. COAL GEOLOGY & EXPLORATION.

井地联合压裂长输管路支撑剂悬浮运移规律模拟研究

Study on suspension and migration law of proppant in long-distance pipeline for ground-coalmine combined hydraulic fracturing

  • 摘要: 井地联合压裂是煤矿井下长钻孔分段压裂的发展趋势之一,压裂液经地面压裂泵加压后通过地面贯通井、煤矿井下长输管路进入煤矿井下长钻孔实施大排量压裂。支撑剂在长输管路中的悬浮运移规律对于优化设计加砂参数、避免管路中砂堵具有重要意义。通过室内实验评价压裂液的流变性能和携砂性能;基于欧拉-颗粒流理论构建数值模拟模型,研究水平管内支撑剂悬浮运移规律及其影响因素;探讨压裂液携带支撑剂运移的流态以及临界沉降流速的计算模型。结果表明: 1%降阻剂的加入能够使活性水压裂液黏度提高3~5倍,支撑剂密度越小,压裂液黏度、砂比越高,支撑剂在压裂液中的沉降速度越小;支撑剂在水平管内的流动受到多因素的综合影响,压裂液流速越小,支撑剂密度和粒径越大,支撑剂在管道底部的沉积越严重,携砂效果越差;随着管路直径的增大,管道出口截面支撑剂体积分数最大的位置由管道中下部移动至管道底部,支撑剂流动对于管路的磨损加重;砂比越大,支撑剂间的相互作用越强,压裂液携砂能力降低;优选采用疏浚技术规范推荐的模型计算活性水携砂条件下的支撑剂临界沉降速度,随着管路直径的增大,所需的临界携砂排量呈指数式增大,提高压裂液黏度可降低携砂所需的临界排量。建立的携砂运移临界排量模型和总结的支撑剂运移规律可对管路直径和压裂液排量进行优化匹配,为井地联合压裂施工提供理论支撑。

     

    Abstract: Ground-coalmine combined hydraulic fracturing is one of the development trend of staged fracturing of long boreholes in underground coal mines. After the fracturing fluid is pressurized by the ground fracturing pump, it enters the long boreholes in underground coal mines through the through-well and long pipeline to conduct large-pump-rate fracturing. The suspension and migration law of proppant in the long pipeline is of great significance for optimizing the sanding parameters and avoiding sand blockage in the pipeline. The rheological properties and sand carrying properties of fracturing fluid were evaluated by laboratory tests. Then, based on the Euler-particle flow theory, a numerical simulation model was constructed to study the transport law of proppant in horizontal pipe. The flow pattern of fracturing fluid and the calculation model of critical settlement velocity were discussed. The results show that the addition of 1% friction reducer can increase the viscosity of active water fracturing fluid by 3~5 times. The smaller the proppant density, the larger the fracturing fluid viscosity and sand concentration, and the smaller the settling velocity of proppant in fracturing fluid. The flow of proppant in horizontal pipe is affected by many factors. The smaller the flow rate of fracturing fluid, the larger the density and particle size of proppant, and the more serious the deposition of proppant at the bottom of the pipe, and the worse the sand carrying effect is. With the increase of pipeline diameter, the maximum volumetric concentration of proppant at the outlet moves from the middle and lower part of the pipeline to the bottom of the pipeline, and the flow of proppant aggravates the wear of the pipeline. The larger the sand concentration is, the stronger the interaction between proppants is, and the sand carrying capacity of fracturing fluid is reduced. The model recommended by dredging technical specification is preferred to calculate the critical settling velocity of proppant under the condition of active water fracturing fluid. With the increase of pipeline diameter, the required critical sand carrying pump rate increases exponentially. Increasing the viscosity of fracturing fluid can reduce the critical sand carrying pump rate. According to the critical pump rate model of sand carrying migration, the pipeline diameter and fracturing fluid pump rate can be optimized and matched. The research results can provide theoretical support for ground-coalmine combined hydraulic fracturing.

     

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