大佛寺和胡家河4~#煤润湿性对比

Comparative study on wettability of 4~# coal from Dafosi and Hujiahe Coalfield

采用室内测定煤的吸—疏水特征实验、煤粉末浸透速度法实验及煤-水溶液界面接触角测定实验,研究了大佛寺与胡家河井田4~#煤体润湿性特征。实验结果显示,煤的吸—疏水特征实验表现为整体胡家河4~#煤样疏水速率高于大佛寺4~#煤样;煤粉末浸透速度法实验表现出大佛寺4~#煤样润湿高度一直处在胡家河之上;接触角测定结果证明胡家河4~#煤样的接触角均大于大佛寺4~#煤样。以上实验结果均表明大佛寺4~#煤润湿性要好于胡家河4~#煤。使用表面活性剂水溶液测定煤的接触角揭示了胡家河4~#煤的润湿性较大佛寺4~#煤更容易被改善。该项研究表明煤层气井压裂过程亦或是排采作业过程,对大佛寺4~#煤储层进行改造要保证预留足够长的时间,而胡家河煤层气的开发要借鉴大佛寺的成功经验,同时利用自身煤储层易疏水优势制定有利的排采制度;向压裂液中加入适当表面活性剂改良煤体润湿性,可以解决煤层气开发过程中出现的压裂液返排不彻底、前期排水时间过长等问题。

To study wettability of 4^#coal in Dafosi and Hujiahe Coalfield,a series of experiments have been conducted including the characteristics of hydrophilic-hydrophobic,experiment of coal powder penetration velocity and coal-water solution interface contact angle measurement.The results show that the overall hydrophobicity rate of 4^#Hujiahe coal sample is higher than that of 4^#Dafosi coal sample,the wetting height of 4^#Dafosi coal sample is always beyond of 4^#Hujiahe coal sample,and the contact angle of 4#Hujiahe coal sample is larger than that of Dafosi 4#coal sample.Comparison of experimental results find that wettability of 4^#coal in Dafosi Coalfield is better than that in Hujiahe coal mine.Measuring the contact angle of coal with surfactant aqueous solution reveals that the wettability of Hujiahe 4^#coal is easier to be improved than that of Dafosi 4^#coal.The contact angle measured by using solution to which has been added surface active agent revealed that the wettability of later is easy to be improved compared with the former.The results indicate that during fracturing and producing process,adequately long time should be reserved to improve the 4^#coal reservoir to improve the permeability and recovery efficiency of coalbed methane in Dafosi Coalfield.The development of coalbed methane in Hujiahe Coal Mine needs to draw on the successful experience from Dafosi CBM development and should take advantage of easy hydrophobic characteristic to formulate favorable production law.By adding appropriate surface active agent,the fracturing fluid can improve the wettability of coal,which can overcome the difficulties fracturing fluid flowback is not complete and the drainage time is too long in the early stage of coalbed methane development.