煤层气水平井压裂多参数智能分段优化研究

Multi-Parameter Intelligent Stage Optimization for Hydraulic Fracturing in Coalbed Methane Horizontal Wells

  • 摘要: 针对煤层气水平井储层非均质性强、传统压裂分段依赖经验且难以定量评价的问题,提出了一种基于多参数融合的压裂分段智能优化方法。选取煤层钻遇率、全烃含量、伽马值和钻时作为主要评价参数,采用正、负向归一化构建综合评价指标,并引入段内品质、段内均质性和段间异质性约束,建立了压裂智能分段优化模型;将动态时间规整用于识别测井曲线局部形态相似性,将粒子群算法用于分段边界全局寻优,形成DTW–PSO混合求解流程。淮南PS−4−2井分段结果表明,优化分段能够较好对应水平段煤层发育、含气性和岩性变化特征;煤层钻遇率和全烃含量对综合评分贡献最大,第1段及第5—10段为有利分段,第2、11段为次有利分段,第3—4段为不利分段。PS−4−2井现场压裂后,产气量持续上升,产水量逐步降低并趋于稳定,压裂改造效果显著,验证了该方法的工程适用性与有效性。研究结果可为煤层气水平井的精细化压裂设计与高效开发提供技术支撑。

     

    Abstract: To address the strong reservoir heterogeneity of coalbed methane (CBM) horizontal wells and the limitations of conventional fracturing stage design, which largely relies on empirical judgment and lacks quantitative evaluation, this study proposes an intelligent stage optimization method for hydraulic fracturing based on multi-parameter integration. Coal seam encounter rate, total hydrocarbon content, gamma ray value, and rate of penetration were selected as the main evaluation parameters. A comprehensive evaluation index was established through positive and negative normalization. Intra-stage quality, intra-stage homogeneity, and inter-stage heterogeneity were introduced as constraints to construct an intelligent optimization model for fracturing stage division. Dynamic time warping (DTW) was used to identify local morphological similarities among logging curves, while Particle swarm optimization (PSO) was applied to globally optimize stage boundaries, forming a DTW-PSO hybrid solution workflow. The method was applied to Well PS-4-2 in Huainan. The results show that the optimized stage division corresponds well to the variations in coal seam development, gas-bearing properties, and lithological characteristics along the horizontal section. Coal seam encounter rate and total hydrocarbon content contribute most significantly to the comprehensive score. Stage 1 and stages 5–10 are identified as favorable intervals, stages 2 and 11 as moderately favorable intervals, and stages 3–4 as unfavorable intervals. After field fracturing stimulation, gas production increased continuously, while water production gradually declined and stabilized, indicating a significant stimulation effect and verifying the engineering applicability and effectiveness of the proposed method. This study provides technical support for refined fracturing design and efficient development of CBM horizontal wells.

     

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