摘要
针对煤层气羽状水平井井身结构的复杂性以及井筒内流体流动特征,建立了考虑井筒摩擦压降、加速度压降及分支流体汇入引起的混合压降影响的煤层气水平井开采数学模型与数值模型。以沁水盆地南部下二叠统山西组3号煤层作为目的层,开展了煤层气水平井开采数值模拟研究。研究结果表明,由于煤层气羽状分支水平井筒变质量流对气、水产量存在影响,导致不同时刻的主支井筒单位长度入流量分布曲线分别呈上凸型和下凹型,且水平井筒指端与跟端之间的压差呈先增加后减少的趋势,故羽状分支水平井筒变质量流在煤层气水平井产能动态评价中不可忽略不计。
For the complexity of pinnate horizontal well configuration and fluid flow features in the wellbore,mathematical and numerical models are established for coalbed methane(CBM) recovery with consideration of wellbore friction pressure drop,acceleration pressure drop and the mixing pressure drop due to inflow from laterals.A case study of numerical simulation was conducted for the 3# coal seam of Shanxi formation in lower Permian in southern Qinshui Basin.The results indicated that variable mass flow along the pinnate horizontal wellbore has a significant effect on gas / water production rate,resulting in convex and concave shapes on the inflow rate curve per unit length of wellbore at different times,as well as a pressure difference trend of increasing then decreasing between toe to heel,therefore the effect of variable mass flow cannot be neglected in evaluation of CBM pinnate horizontal well productivity.
出处
《特种油气藏》
CAS
CSCD
北大核心
2013年第4期106-109,156,共4页
Special Oil & Gas Reservoirs
基金
国家科技重大专项"煤层气数值模拟与开发综合评价技术"(2011ZX05038-004)
国家"973"项目"高丰度煤层气富集机制及提高开采效率基础研究"(2009219606)
中央高校基本科研业务费专项资金资助项目"低煤阶煤层气开发井网自动优化方法及应用研究"(10CX04011A)
关键词
煤层气
水平井
井筒变质量流
混合压降
数值模拟
coalbed methane
horizontal well
variable mass flow in wellbore
mixing pressure drop
numerical simulation
