摘要
煤层气开采方式的本质是排水降压采气,了解煤层的降压效果对排采制度的确定有着积极的意义。通过建立圆形封闭煤层中考虑煤层气解吸作用的两井不定常渗流模型,利用有限元方法求得了其数值解,分析解吸作用对理论特征曲线的影响。计算结果表明,煤层气解吸具有减缓压力传播的作用;分析不同性质邻井对理论曲线特征的影响,给出存在邻井影响时的压力场发展规律。提出压力场的4种描述方法,分析邻井性质、邻井流量变化,以及外边界性质对煤层压力场分布的影响,得到不同条件下煤层气压力场的变化规律。
The nature of CBM production is draining water to drop pressure and produce methane.So it is important to know the pressure dropping effect for producing methane.By considering CBM desorption effect,mathematical model for unsteady seepage flow is developed in circle bounded coalbed with two wells.The numerical solutions are obtained by using the finite element method.The desorption effects on the well test type curve are analyzed in detail.The results show that CBM desorption decrease the pressure wave transmitting velocity in the coal bed.The effect of the neighbor well property on type curve is also analyzed for describing the development of pressure field.Four kind of description methods are intrduced and evaluated in this paper.The effects of well property,flow rate of the neighbor well and property of the outer boundary on the pressure field are analyzed for the pressure field changing under different conditions.
出处
《油气井测试》
2010年第6期64-70,共7页
Well Testing
基金
国家重大专项"大型气田及煤层气开发"专项支持
课题编号2009ZX05038001
关键词
煤层气
压力场
试井
解吸
coalbed methane,pressure field,well test,desorption
作者简介
[联系作者]刘曰武，男，研究员，主要从事渗流力学及油气藏工程方面的研究。
