煤体结构是影响煤层气井压裂改造效果的关键因素，准确预测煤体结构分布规律，厘清不同煤体结构组合模式对压裂改造的影响程度对于提高压裂工艺的适应性尤为重要。基于延川南煤层气田岩心和测井曲线建立煤体结构识别模板，开展煤体结构模式定量化识别和划分，明确不同模式的分布规律及主控因素，并分析不同模式的压裂改造效果，结果表明：煤体结构可以划分为硬煤和软煤2种类型，纵向上非均质性强，呈现为“两类五型”的组合模式：单层结构(硬煤、软煤）、多层叠加型结构(硬煤-软煤、软煤-硬煤、软煤-硬煤-软煤），不同模式的形成主要受构造和沉积共同控制，平面分布上以单层硬煤为主，单层软煤主要发育在气田东北部以及中部断裂带附近，其他类型在低序级断层附近局部发育；整体上可改造性：单层硬煤>多层软硬煤叠加结构煤>单层软煤，与开发效果的规律具有一致性，其中多层软硬煤叠加结构煤中硬煤厚度占比≥60%，产气效果较好；上述煤体结构模式的差异性导致常规压裂工艺存在局限性，根据不同煤体结构模式的改造效果差异，提出了针对性的压裂优化建议改善开发效果。研究成果对气田后期压裂施工中工程甜点段优选以及压裂方案优化具有较好的指导意义。

coal structure is the key factor affecting the fracturing effect of coalbed methane well. It is very important to accurately predict the distribution of coal structure and clarify the influence degree of different coal structure combination types on fracturing reform to improve the adaptability of fracturing technology. Based on the core drilling and logging response curve of Yanchuannan coalbed gas field, we established the recognition template of coal structure to recognize and divide the coal structure pattern, and clarified the distribution rules and main control factors of different patterns, as well as analyzed the transformability of different coal structure combination modes. The results show that the coal structure in the gas field can be divided into hard coal and soft coal, vertically, the coal body structure presents the combination mode of “two categories and five types”: single layer structure (single layer hard coal, single layer soft coal), multilayer structure (upper hard coal-lower soft coal, upper soft coal - lower hard coal, upper soft coal-middle hard coal-lower soft coal);The formation of different modes is affected by the structure and deposition, and the distribution on the plane is dominated by single-layer hard coal, single-layer soft coal mainly develops in the northeast and near the central fault zone of the gas field, and other types develop locally near low-order faults. On the whole, the difficulty of fracturing reconstruction is: single layer soft coal > soft and hard coal combination structure coal > single layer hard coal, which is consistent with the law of development effect. When the thickness of hard coal is more than 60% in the soft and hard coal combination structure, the cumulative gas production is better. The differences of the above coal body structure modes lead to limitations of conventional fracturing technology. Based on the difference of the transformation effect of different coal structure modes, targeted fracturing optimization suggestions are put forward to improve the development effect. The research results have a good guiding significance for the optimization of Engineering sweet spot section and fracturing scheme in the later stage of gas field fracturing construction.

0 引言

1 研究区概况

2 煤体结构模式及控制因素

   2.1 煤体结构测井识别

   2.2 模式建立及分布特征

   2.3 控制因素

3 不同煤体结构模式的改造效果及分析

   3.1 不同煤体结构模式的改造效果

   3.2 压裂优化建议

4 结论