Duong产量递减模型在窄河道致密砂岩气藏中的应用——以中江气田沙溪庙组气藏为例

Application of Duong Production Decline Model in Narrow Channel Tight Sandstone Gas Reservoir—By Taking Zhongjiang Gas Reservoir as an Example

摘要: 中江气田沙溪庙组气藏属窄河道致密砂岩气藏，大部分气井需压裂后测试获产，气井渗流通过较长时间达到边界流，用常规Arps方法进行气井产量预测误差较大。从理论角度，分析传统Arps方法和适用于页岩气产量递减分析模型——Duong方法的内在联系，结合中江气田气井生产实践，拓展研究Duong模型的使用条件及适用性。研究结果表明，Duong模型是Arps模型的非线性扩展，本质上是在双对数坐标下的趋势预测，可用于致密砂岩气藏气井产量预测；在Duong模型研究的基础上，进一步验证该模型也适用于以径向流为主导的气井；对于连续生产、多次调产、压恢井三种情况下的气井，要重新选取初始点进行拟合。通过实例验证，Duong模型对于致密砂岩气藏处于非稳态流气井产量预测具有较强的实用性。

Abstract: Sha Ximiaoformation of Zhongjiang gas field belongs to narrow channel tight sandstone gas re-servoir. Most gas wells need to be fractured for production. It takes a long time for gas well see-page to reach the boundary flow, so the conventional Arps method has a large error in predicting gas well production. Compared with Duong and Arps production decline model, the intrinsic relation between the two models is demonstrated theoretically. Combined with the production practice of gas Wells in Zhongjiang gas field, the application conditions and applicability of Duong production decline model are analyzed. The Duong production decline model is a nonlinear extension of the Arps decline model, which can be applied to gas wells dominated by fracture flow as well as radial flow. The applicability of Duong production decline model under three gas wells conditions such as continuous production, production regulation and pressure recovery, is analyzed in close combination with the field practice, which provides a theoretical basis for better use of Duong model in tight sandstone gas reservoirs. It provides a new method for calculating reasonable production and reserves of gas wells, which has important practical value.