Analytical solution of coal-bed methane migration with slippage effects in hypotonic reservoir

Using theoretical analysis, the single-phase gas seepage mathematical model influenced by slippage effects was established. The results show that the pressure of producing wells attenuates more violently than the wells without slippage effects. The decay rate of reservoir pressure is more violent as the Klinkenherg factor increases. The gas prediction output gradually increases as the Klinenberg factor increases when considering gas slippage effects. Through specific examples, analyzed the law of stope pore pressure and gas output forecast changing in a hypotonic reservoir with slippage effects. The results have great theoretical significance in the study of the law of coal-bed methane migration in hypotonic reservoirs and for the exploitation of coal-bed methane.

基于生命周期阶段的农业产业集群形成和演化机理分析

农业产业集群的聚集过程是在流入效应、流出效应和乘数效应共同交互作用下完成和演变的。在农业产业集群的孕育阶段,以自然资源优势为主的关键要素是产生流入效应的基础,乘数效应还没有真正充分发挥作用;在成长阶段,特定区域空间上的分工与专业化得到发展,乘数效应发挥较强作用,由专业化分工所带来的外部规模经济和范围经济为成长阶段带来了新的流入效应。在成熟阶段,集群已形成了一个完整的产业价值体系,乘数效应充分发挥作用,在原有流入效应的基础上,基于社会资本形成的创新网络又为集群带来了新的流入效应。在构建本地农业产业集群时应充分考虑农产品特点和当地农业资源禀赋情况,大力发展龙头企业,鼓励农户创业,同时政府要为农业产业集群的发展营造良好的外部发展环境。