Abstract The development of naturally fractured gas reservoirs often requires the deployment of rigorous techniques for production data analysis incorporating dual-porosity gas behavior. It has been a prominent problem to linearize and analytically solve the governing equations for dual-porosity gas systems. This study applies a pseudo-pressure-based interporosity flow equation to derive a density-based rate-transient analysis method to accurately predict the gas production rate and estimate the amount of original gas in place ( G i ) for the systems. The methodology also predicts the gas production rate by transforming the response of its liquid counterpart via a decoupling of the pressure-dependent effects using dimensionless depletion-driven parameters. For the first time, the density-based flowing material balance method is derived for the dual-porosity gas reservoir. More than that, an innovative fracture productivity equation that was missing for the dual-porosity system is derived as well. This study provided detailed derivations for the model and relationship used in past density-based dual-porosity rate-transient analysis. The dual-porosity productivity equation and the relationship between average matrix pseudopressure and average fracture pseudopressure are rigorously derived. The rescaling relationship between the dual-porosity liquid solution and the dual-porosity gas solution is also demonstrated in detail. An appropriate interporosity flow equation for gas is used. Based on that, the results show that the density-based approach is able to successfully capture the dual-porosity behavior of gas for constant bottomhole pressure condition.

中文翻译：

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使用基于密度的方法对天然压裂气藏进行储量评估的分析双孔气模型

摘要 天然裂缝性气藏的开发通常需要采用严格的生产数据分析技术，结合双孔隙度气体行为。双孔隙气体系统控制方程的线性化和解析求解一直是一个突出的问题。本研究应用基于伪压力的孔隙度流动方程推导出基于密度的速率瞬态分析方法，以准确预测产气速率并估计系统的原始天然气量 (G i )。该方法还通过使用无量纲耗尽驱动参数解耦压力相关效应来转换其液体对应物的响应来预测气体生产率。首次，推导了双孔隙气藏基于密度的流动物质平衡方法。不仅如此，还推导出了双孔隙度系统所缺少的创新压裂产能方程。这项研究为过去基于密度的双孔隙率瞬态分析中使用的模型和关系提供了详细的推导。严格推导出双孔隙度产能方程以及平均基质假压力与平均裂缝假压力之间的关系。双孔液体溶液和双孔气体溶液之间的重标度关系也得到了详细论证。使用适当的气体孔隙度流动方程。基于此，