页岩气产量递减典型曲线的不确定性分析方法

为降低页岩气产量评价风险,指导和优化页岩气开发,研究了页岩气产量递减的不确定性分析方法。利用双曲递减理论,基于某页岩气区块19口井的生产动态数据,建立每一口井的典型曲线,用P90,P50和P10表示典型曲线的实现概率,提出了页岩气产量递减典型曲线的不确定性分析方法。利用该方法得到该区块P90,P50和P10典型曲线参数,计算的最终可采储量分别为0.26×108,0.91×108和2.11×108 m3,而采用确定性方法得到的最终可采储量为1.01×108 m3。结果表明,确定性分析方法得到的典型曲线较接近于P50典型曲线。利用不确定分析方法评价页岩气产量递减典型曲线,可以为产量评价风险提供参考,指导开发方案设计和优化。 

An Uncertainty Analysis Method on Typical Production Decline Curve for Shale Gas Reservoirs

To reduce the risk in production evaluation and optimize the development program of shale gas play,an uncertainty analysis method is proposed to analyze the production decline type curve for shale gas reservoirs.According to the hyperbolic decline theory,a typical curve for each well was obtained based on the production data of 19 shale gas wells.The probability P90,P50 and P10 of typical curves show up were suggested based on the type curve parameters obtained from uncertainty analysis method.With this method,the P90,P50 and P10 typical curves for a shale gas block were obtained,and the EURs corresponding to P90,P50,P10 are 0.26×108 m3,0.91×108 m3 and 2.11×108 m3.Results show that the P50 typical curve approximates to that from conventional certainty analysis method.Uncertainty analyis method can be used as a reference to optimize the development program of shale gas.