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页岩气多级压裂形成的复杂裂缝网络会改变其原有的气体渗流模式,形成多个独有的流动阶段。因此,常规的产能模型不能有效模拟其压力、流量变化规律。为了增加页岩气产能模拟精度和对压裂施工优化做出指导,在耦合三线性渗流和球形双重介质渗流模型的基础上,考虑解吸和滑脱等机理,建立了改进的三线性流产能预测模型,并进行了解析求解和数值反演。计算结果表明,页岩气的解吸对提高单井产能,延长稳产期具有重要意义;储层中的微裂缝能够通过控制气体在基质与人工裂缝之间的窜流最终影响页岩气井产能;人工裂缝导流能力对页岩气井产能的影响覆盖了整个生产周期的中前段,然而随着人工裂缝导流能力的增加,产能的增长幅度变缓,证明了页岩气藏不需追求高导流能力裂缝的理论,缝间距主要影响线性流时间的长短;汇聚效应在投产初期对产能具有不可忽视的影响。研究结果对于深化页岩气井生产动态认识和提高页岩气藏开发效率具有重要意义。
The complicated fracture network formed by multi-stage fracturing of shale gas will change its original gas seepage mode to form several unique flow stages. Therefore, the conventional capacity model can not effectively simulate the pressure and flow changes. In order to increase the shale gas productivity simulation accuracy and guide the optimization of fracturing construction, based on the coupled three-linear seepage and spherical dual medium seepage model, considering the mechanism of desorption and slippage, an improved prediction model of tri-linear flow capacity , And carried out analytic solution and numerical inversion. The calculated results show that desorption of shale gas is of great significance for improving single-well productivity and prolonging stable production period. The micro-fractures in reservoirs can ultimately affect the productivity of shale gas wells by controlling the gas cross-flow between the substrate and artificial fractures. The influence of fissure diversion ability on shale gas well productivity covers the middle section of the whole production cycle. However, with the increase of artificial fissure diversion capacity, the growth rate of productivity slows down, which proves that shale gas reservoir does not need to pursue high diversion The theory of capacity cracks, seam spacing mainly affects the length of linear flow time; convergence effect in the early production has a non-negligible impact on capacity. The research results are of great significance for deepening the dynamic understanding of shale gas production and improving the development efficiency of shale gas reservoirs.