延川南区块深层煤层气井产能主控因素

Research on key factors of CBM well productivity in deep strata inblock of south Yanchuan

  • 摘要: 深层煤层气井产能高低及影响因素认识不清,制约了其商业化开发进程。对延川南万宝山构造带煤层气生产特征及产能情况进行了总结,从煤层气资源条件、煤层气解吸难易程度和渗流条件3个方面对产能影响因素进行了研究。结果表明,渗透率与含气量是影响产能的主要因素:渗透率大于0.3×10-3μm2和含气量高于15 m3/t是稳定产气量大于1 000 m3/d的前提条件。含气量主要受埋深和水动力条件影响,埋深越大,水动力条件越弱,含气量越高;渗透率主要受地应力、形变和裂缝发育情况控制,低地应力区和局部构造高点附近渗透率较高。根据渗透率与含气量将构造带划分为高渗高含气、高渗低含气、低渗高含气、低渗低含气4个区。其中,高渗高含气区产液量中等,产气能力高;高渗低含气区以异常高产液、低产气井为主;其他两区产液量和产气能力较低。

     

    Abstract: Unclear understanding on the factors influencing the productivity of deep buried CBM wells has restricted the commercial exploration. Firstly, the paper summarized the style and capacity of CBM production, then analyzed the factors influencing productivity from resource, difficulty of desorption and fluid condition. The results show that permeability and gas content are the major influence factors of productivity. The constant gas rate of flow is above 1 000 m3/d when the permeability is more than 0.3×10-3 μm2 and the gas content is more than 15 m3/t. Gas content is mainly influenced by depth and hydrodynamic condition, while permeability is mainly controlled by crustal stress, deformation and crack condition. Based on permeability and gas content, the block was divided into four parts and the productivity of each part was evaluated. The correlation between the productivity and fracturing operation parameters are poor, which revealed that the effect of different fracturing operation was basically the same in current technological level.

     

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