摘要
煤粉问题制约着煤层气井高效开发,煤粉聚集会导致储层渗透率和产气能力降低。为了查明水矿化度和水化学类型对煤粉聚集的影响,针对水化学类型为NaHCO_(3)、Na_(2)SO_(4)、CaCl_(2)和MgCl_(2)和水矿化度为3000mg/L、6000mg/L、12000mg/L、18000mg/L的水溶液,开展了不同矿化度和水化学类型的水对煤粉聚集影响的实验。从煤粉聚集沉降情况观察、煤粉悬浮液中煤粉质量浓度及煤粉粒度分布,探究了煤粉在不同矿化度和水化学类型的煤粉悬浮液中的聚集沉降特征。结果表明:随着煤粉悬浮液静置时间的增长,各水化学性质煤粉悬浮液的颜色均不同程度的变浅,逐渐出现分层。在矿化度为3000~18000mg/L的煤粉悬浮液中,随着悬浮液矿化度的增加,煤粉在悬浮液中的聚集性增强。在四种水化学类型的悬浮液中,煤粉在CaCl_(2)和MgCl_(2)煤粉悬浮液中聚集最强,在NaHCO_(3)煤粉悬浮液中聚集最差。根据扩展DLVO理论,煤粉悬浮液中Ca^(2+)、Mg^(2+)、Na^(+)和H^(+)等阳离子可中和煤粉颗粒表面的双电层电荷,高价的Ca^(2+)、Mg^(2+)所带的正电荷比低价的Na^(+)和H^(+)所带的正电荷多,煤粉颗粒对Ca^(2+)、Mg^(2+)具有较强的吸附能力,由于Ca^(2+)与Mg^(2+)离子半径更大,压缩双电层的能力较强,因此,高矿化度的CaCl_(2)和MgCl_(2)地下水对煤粉聚集沉降较强。该成果为煤层气煤粉管控措施的制定提供理论依据。
The aggregation of coal fines restricts the efficient development of coalbed methane and can cause the reduction of reservoir permeability and gas productivity.To find out the influence of water salinity and hydrochemical type on the aggregation of coal fines,the aggregation experiments of coal fines in water with the different salinity and hydrochemical types were conducted on the water with the hydrochemical type of NaHCO_(3),Na_(2)SO_(4),CaCl_(2) and MgCl_(2) and the salinity of 3000 mg/L,6000 mg/L,12000 mg/L,18000 mg/L.The aggregation and sedimentation characteristics of coal fines in a water suspension with different salinity and hydrochemical types were investigated from the suspension observation,the concentration of coal fines,and the particle size distribution of coal fines in suspension.The results show that As the standing time of the suspensions increases,the color of coal fines suspension with different hydrochemical types becomes lighter,and the stratification of coal fines suspension gradually appears.The aggregation of coal fines in suspension is enhanced as the increase of suspension salinity in the suspension with the salinity of 3000~18000mg/L.Coal fines have the strongest aggregation in CaCl_(2) suspension and MgCl_(2) suspension,and the worst aggregation in NaHCO_(3) suspension among the four hydrochemical types of suspension.According to the extended DLVO theory,cations such as Ca^(2+),Mg^(2+),Na+and H+in the suspension can neutralize the electric double-layer charge on the surface of coal fines.There are many positive charges,and the coal fines have strong adsorption capacity for Ca^(2+)and Mg^(2+).Due to the larger ionic radius of Ca^(2+)and Mg^(2+),the ability to compress the electric double layer is stronger.The powder aggregates and settles strongly.It provides a theoretical basis for the formulation of coalbed methane coal fines management and control measures.
作者
魏迎春
张劲
王扬眉
崔茂林
刘子亮
王安民
曹代勇
WEI Yingchun;ZHANG Jin;WANG Yangmei;CUI Maoin;LIU Ziiang;WANG Anmin;CAO Daiyong(College of Geoscience and Surveying Engineering,China University of Mining and Technology(Beijing),Beijing 100083)
出处
《中国煤炭地质》
2023年第6期1-8,共8页
Coal Geology of China
基金
国家自然科学基金项目(41972174、41402134)
中国矿业大学(北京)大学生创新训练项目(202202025)。
关键词
煤层气
煤粉
水矿化度
水化学类型
聚集沉降
coalbed methane
coal fines
water salinity
hydrochemical type
aggregating and settlement
作者简介
第一作者:魏迎春(1977-),女,山东巨野人,博士,教授,从事煤与煤层气地质、勘探与开发方面的教学和科研工作。E-mail:wyc@cumtb.edu.cn。
