涪陵焦石坝区块页岩气井产量递减典型曲线应用研究

Application Study on Typical Production Decline Curves of Shale Gas Wells in the Fuling Jiaoshiba Block

  • 摘要: 为研究涪陵焦石坝区块页岩气井产量递减规律和影响产量递减典型曲线的主要因素,依据该区块典型页岩气井生产数据,采用拟合方法,建立了归一化拟产量与物质平衡时间的递减典型曲线,分析了气井初始产能、生产时间、配产、产水量、地层压力和井底流压对产量递减典型曲线和可采储量评价的影响,并研究了产量递减典型曲线在页岩气井可采储量评价、合理配产、流动阶段划分等3个方面的应用问题。研究表明,采用产量递减典型曲线评价可采储量时,既考虑了研究井目前的生产特征又可反映后期变化特征,因此该方法较常规的物质平衡法、弹性二相法、经验类比法更为可靠;页岩气井产能和生产规律是一个动态变化的过程,因此应动态合理配产,注意分区、分井、分阶段的差异性;对产量递减典型曲线取归一化拟产量和物质平衡时间的双对数曲线后,在完整的生产周期内可根据斜率判别页岩气井所处的流动阶段。该研究结果可为涪陵焦石坝区块页岩气井可采储量评价、合理配产和区块开发方案的设计提供参考和指导。

     

    Abstract: To reveal the production decline pattern and the influencing factors of shale gas wells in Fuling Jiaoshiba Block, a typical decline curve of normalized quasi-production and material balance time by means of fitting method was developed on the basis of typical shale gas production data. At the same time, the impact of initial production capacity, production history, production allocation, water production, formation pressure and bottom hole flow pressure value accuracy on the typical production decline curve and recoverable reserve evaluation were also studied. In addition, applications of the typical production decline curve in recoverable reserve evaluation, reasonable production allocation and flow stage division were also analyzed. The results showed that the typical production decline curve used in recoverable reserve evaluation can take account of current production characteristics and production changes of the well, it demonstrates that this method is more reliable than the conventional material balance method, the elastic 2-phase method and empirical analogy method. Productivities and production patterns of shale gas wells change dynamically, so production is allocated in a rational manner. In addition, great attention should be paid to the difference among blocks, wells and production stages. By using the double logarithmic curve of normalized quasi-production and material balance time, the flow stage of shale gas wells can be determined based on the slopes in a complete production cycle. The results can provide references and guidance for evaluation of recoverable reserve, the rational production allocation and block development plan design of shale gas wells in the Fuling Jiaoshiba Block.

     

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