沁水盆地郑庄区块煤层气开发地质单元划分及开发方式优化研究

为了找出不同煤储层条件下煤层气的最优开发方式，结合静态地质资料与动态生产资料，利用数值 模拟技术，对郑庄区块煤层气单井产能主控因素进行了分析，并对开发地质单元进行了划分及开发方式的优化。结果表明，区域性的单井产量差异是由于水力压裂技术与煤储层地质特征不匹配造成的，单井产量受煤体结构、解吸压力及地应力等地质因素的控制；郑庄区块可划分为4 类开发地质单元，其中Ⅰ 类和Ⅱ类开发地质单元适合直井的开发方式，Ⅲ类和Ⅳ 类开发地质单元适合多分支水平井的开发方式。Ⅰ类开发地质单元最优直井井距为280 m，单井具有2 000 m3/d 以上的产气能力，收益率为10.8%，经济效益好；Ⅱ类开发地质单元最优直井井距为240 m，单井具有800～2 000 m3/d 的产气能力，收益率为10.2%，经济效益较好；Ⅲ类开发地质单元最优分支间距为80 m，单井具有3 000 m3/d 的产气能力，收益率为7.2%，经济效益较好；Ⅳ 类开发地质单元最优分支间距为60 m，单井具有3 200 m3/d 的产气能力，但收益率仅为3.1%，经济效益差，不具备投资价值，需等待工程技术提高后进行开发。

Geological unit division and development model optimization of coalbed methane: a case study from Zhengzhuang block in Qinshui Basin

In order to plan the optimal development model for different coal reservoirs, combined with production data and static geological data, the numerical simulation technology was applied to analyze the main controlling factors of single well productivity, and to divide geological unit of Zhengzhuang block and optimize the development model.The result shows that the difference of productivity of vertical well is mainly caused by the mismatch of hydraulic fracturing technique with geological characteristics of regional coal reservoir. The single well productivity is controlled by coal body structure, desorption pressure and ground stress. Zhengzhuang block was divided into four types of development geological unit. According to the numerical simulation, the reservoirs in type Ⅰ and Ⅱ development geological units are suitable for vertical well hydraulic fracture, and the reservoirs in the type Ⅲ and Ⅳ development geological units are suitable for multi-branched horizontal well. The optimized well spacing is 280 m in the type Ⅰdevelopment geological unit, the single well productivity can reach 2 000 m3/d or above, and the yield rate is 10.8%.The optimized well spacing is 240 m in the type Ⅱ development geological unit, the single well productivity can reach 800-2 000 m3/d, and the yield rate is 10.2%. The optimized well spacing is 80 m in the type Ⅲ development geological unit, the single well productivity is 3 000 m3/d, and the yield rate is 7.2%. The optimized well spacing is 60 m in the type Ⅳ development geological unit, the single well productivity is 3 200 m3/d, and the yield rate is only 3.1%, so it is risk to put into production under current economic technology.