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、自然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,形成了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段至第10段为有利段,第2段和第11段为次有利段,第3段和第4段为不利段。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 challenges of strong reservoir heterogeneity in coalbed methane (CBM) horizontal wells and the reliance on empirical experience with difficulty in quantitative evaluation for conventional fracturing stage design, an intelligent fracturing stage optimization method based on multi-parameter fusion was proposed. Coal seam encounter rate, total hydrocarbon content, gamma ray value, and drilling time were selected as the main evaluation parameters. Positive and negative normalization was employed to construct a comprehensive evaluation index, and constraints including intra-stage quality, intra-stage homogeneity, and inter-stage heterogeneity were introduced to establish an intelligent fracturing stage optimization model. Dynamic time warping (DTW) was used to identify local morphological similarities among logging curves, and the particle swarm optimization (PSO) algorithm was applied for global optimization of stage boundaries, forming a hybrid DTW-PSO solution workflow. The stage design results of Well PS-4-2 in Huainan demonstrated that the optimized stage corresponded well to the characteristics of coal seam development, gas-bearing properties, and lithological variations along the horizontal section. The coal seam encounter rate and total hydrocarbon content contributed the most to the comprehensive score, with Stage 1 and Stages 5–10 identified as favorable stages, Stages 2 and 11 as secondary favorable stages, and Stages 3–4 as unfavorable stages. After field fracturing of Well PS-4-2, the gas production continued to rise, while the water production gradually decreased and stabilized, which indicated a significant fracturing stimulation effect and validated the engineering applicability and effectiveness of the proposed method. The research results can provide technical support for refined fracturing design and efficient development of CBM horizontal wells.

     

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