沁水盆地南部煤层气井排采伤害判别模式

为分析煤层气排采生产过程中储层伤害对煤层气井产能的影响,以沁水盆地南部成庄区块为例,对22口煤层气井排采生产特征进行了分析,划分了高、中、低产井和产水井,界定了不同产能井排采伤害发生的时间,建立了煤层气井的排采伤害判别模式。研究结果表明:成庄区块高、中、低产井和产水井排采前期易产生速敏效应,中期是地层气锁的高发期,后期会出现应力闭合伤害;3种主要排采伤害中,气锁发生的可能性比煤粉堵塞要大,速敏出现概率又比应力闭合大;高产井在生产过程中一般会发生一种类型的伤害,中产井中出现2种伤害类型的几率增大,低产井与产水井多为多种伤害类型组合甚至出现伤害的耦合效应。

Discrimination model on damage mechanism in the extraction process of CBM wells in Southern Qinshui Basin

In order to analyze the effect of reservoir damage on the productivity of CBM wells during its production process，the Chengzhuang Block in Southern Qinshui Basin was investigated.The production characteristics of 22 CBM wells were analyzed and divided into high，medium，low productivity well and drainage well.Also，the occurrence time of the drainage damage of different production wells was defined.At the same time，the discrimination model of damage mechanism in the extraction process of CBM wells was established.The results show that the velocity sensitivity effect is easy to occur in the early stage of the production，and the peak period of gas lock appears in its middle stage，and the stress closure damage occurs in its late stage.In the above damages，that always occurs in high to low productivity wells in Chengzhuang Block，the possibility of gas lock is higher than that of the velocity sensitivity effect，while the velocity sensitivity effect occurrence probability is higher than that of the stress closure.The high productivity well usually results in one type damage during its production process，and the medium productivity well has a higher chance to occur two types damages，while the low well and drainage well normally result in a variety of damage types combination and even have the damage coupling effect.