无因次产水图版预测煤层气井产水量研究

Predicting Water Production of Coalbed Methane Wells with Type Curves

目前,煤层气井产水量预测主要采用数值模拟方法,该方法可以较好地描述煤层气赋存、运移及产出机理,但应用起来较为繁琐、费时。为此,以山西省南部沁水盆地南部樊庄区块实际地质和动态资料为依据,通过引入无因次参数组合绘制煤层气井无因次产水曲线,并对影响该曲线的煤层面积、裂缝孔隙度、渗透率等14个参数进行了敏感性分析,绘制了无因次产水图版,形成了一套简单、可靠、快速预测煤层气井产水量的方法,并对方法的准确性进行了验证。结果表明,表皮系数、未饱和度和气、水相相对渗透率对无因次产水曲线的影响较大,其他参数对其影响较小,误差均小于10%;无因次产水图版预测煤层气井产水量与实际日产水量误差为6.78%,具有较高的预测精度,可供现场应用。

Numerical simulation was an effective method for predicting the water production of coalbed methane(CBM) wells,which could describe the gas storage,migration and production mechanism.But its application was complicated and time consuming.Therefore based on the actual geologic and dynamic data of Fanzhuang Block of Qingshui Basin in the south of Shanxi,the water production type curve was developed by introducing dimensionless parameter assemblage and the sensitivity of 14parameters such as coalbed area,fracture porosity and permeability influencing the curve was analyzed,a dimensionless chartboard of water production was developed,a sets of new methods for simple,reliable and rapid prediction of water production were established.The accuracy of the methods was verified.The results show that the skin factor,the degree of undersaturation and the relative permeability curve have higher effect on the curve while other parameters have little effect on it and the error is all within 10%.The curve can accurately predict the water production,and the error is 6.78% with higher accuracy,it can be used in the oilfields.