深层页岩气井气水两相产能预测

Production forecast of deep shale gas wells based on gas-water two-phase flow

王西凤 黄世军 赵凤兰 张娇娇

WANG Xifeng HUANG Shijun ZHAO Fenglan ZHANG Jiaojiao

中国石油大学(北京)石油工程学院

School of Petroleum Engineering, China University of Petroleum (Beijing), Beijing 102249, China

气水两相流动对深层页岩气井产能具有重要影响，研究气水两相生产动态对于评估增产效果具有重要意义。考虑压裂液侵入区域(水侵层)和裂缝的气水两相流动，建立了深层页岩气多段压裂水平井的产能预测模型，并结合物质平衡方程，采用逐次迭代方法获得模型的半解析解。利用商业数值模拟器和矿场生产数据验证了模型的可靠性与实用性，并分析了水侵层敏感性参数(水侵层宽度、含水饱和度和渗透率)对产能的影响。研究结果表明：所建立模型能够合理预测深层页岩气井产能；水侵层宽度及含水饱和度越高，页岩气产量越低，但水侵层渗透率越高，页岩气产量越高，水侵层对页岩气产能的影响是多个参数协同作用的结果；水侵层宽度对页岩气20年累积产气量及产水时间影响最大，而对初期产气量影响最大的是水侵层含水饱和度。新模型为深层页岩气井产能预测精度的提高提供了理论基础和科学依据。

Two-phase flow of gas and water is vital for the production capacity of deep shale gas wells, and it is of great significance to investigate the two-phase production performance of gas and water, for evaluating the reservoir stimulation effects. The production forecast model of multi-stage fractured horizontal wells of deep shale gas was built, considering the two-phase gas-water flow in the fracturing fluid-invaded zone (water invasion zone) and fractures. The presented model was combined with the material balance equation, and the semi-analytical solutions of this model were obtained via the successive iteration approach. The liability and practicability of this model were validated using both the commerical numerical simulator and field production data, and the effects of the sensitive parameters of the water invsion zone (width, water saturation and permeability of the water invasion zone) on production capacity of wells were analyzed. The results showed that the built model can deliver reasonable prediction of production capacity of deep shale gas wells. The shale gas production drops with the expanding width and increasing water saturation of the water invasion zone, and yet climbs up, with the growing permeability of the water invasion zone. The shale gas production capacity is subjected to the joint effects of the multiple parameters of the water invasion zone. Specifically, among the width, water saturation and permeability of the water invasion zone, the water invasion zone width has the largest effects on the 20-year cumulative gas production and water production time, while the intial gas production is most affected by the water saturation of the water invasion zone. The new model provides a theoretical basis and scientific basis for improving the accuracy of productivity prediction in deep shale gas wells.

10.13639/j.odpt.202302067