摘要
针对深部煤层气井颗粒组分复杂且地温较高的特点,基于油气井砂沉降公式引入颗粒组分占比,综合考虑颗粒组分及井液温度的影响,推导出适用于深部煤层气井垂直井筒的颗粒沉降末速计算公式.并利用液携试验台进行试验,揭示深部煤层气井垂直井筒液流携带颗粒运移特性.结果表明:煤层气井井筒中存在漂浮物形式的低密度煤质颗粒,该部分颗粒在井液流速很低时随井液排出井筒;随着井液流速增加泥质颗粒开始排出井筒,在流速达到0.05~0.06 m/s范围时,颗粒携带率达到稳定期;此后流速继续增大,较小的砂质和夹矸等颗粒随井液排出,当井液流速达到0.08 m/s时,颗粒携带率基本稳定.试验过程共出现3个稳定期,造成这种现象的原因是煤层气井煤质、泥质、砂质及不同比例混合颗粒导致颗粒组分复杂,这也正是煤层气井液携颗粒与油井携砂的主要区别.这为经济有效的解决煤层气井煤粉颗粒沉积问题、设计井筒排煤粉方案奠定了基础.
In view of the complex particle composition and high ground temperature of deep CBM wells, the proportion of particle composition is introduced based on the oil well sand settlement formula. Considering the effects of particle composition and well fluid temperature comprehensively, a formula for calculating the end velocity of particle settlement in the vertical wellbore of deep coalbed methane wells was derived. And using the liquid-carrying test bench, tests were carried out to reveal the characteristics of particle migration in the vertical wellbore of deep coalbed methane wells. The results show that there were low-density coal particles in the form of suspended solids in the wellbore of CBM wells, which were discharged from the wellbore with the well fluid when the flow rate of the well fluid was very low. As the flow velocity of the well fluid increased, the mud particles began to be discharged from the wellbore. When the velocity reached the range of 0.05—0.06 m/s, the particle carrying rate reached a stable period. After that, the flow velocity continued to increase, the small sand and gangue particles were discharged with the well fluid. When the well fluid velocity reached 0.08 m/s, the particle carrying rate was basically stable. There were three stable periods in the test process. The reason for this phenomenon was that the coal quality, mud quality, sand quality and different proportions of mixed particles in CBM wells lead to complex particle composition. And this is also the main difference between CBM well fluid carrying particles and oil well carrying sand. this paper lays a foundation for economically and effectively solving the problem of coal particle deposition in coalbed methane wells, and designing a wellbore coal discharge plan.
作者
张芬娜
宋云飞
朱洪迎
石怀龙
韩帅
胡皓
刘衍聪
ZHANG Fenna;SONG Yunfei;ZHU Hongying;SHI Huailong;HAN Shuai;HU Hao;LIU Yancong(College of Mechanical and Electrical Engineering,China University of Petroleum,Qingdao,Shandong 266580,China;China United Coalbed Methane Limited Liability Company,Beijing 100108,China)
出处
《中国矿业大学学报》
EI
CAS
CSCD
北大核心
2021年第6期1060-1066,共7页
Journal of China University of Mining & Technology
基金
国家科技重大专项项目(2016ZX05066004-002,2017ZX05064004-007)
山东省自然科学基金面上项目(ZR2020MD038)。
关键词
煤粉颗粒组分
颗粒沉降
深煤层
液携试验
composition of pulverized coal particles
particle sedimentation
deep coal seam
liquid carried particle test
