考虑裂缝导流能力时效性的多级压裂水平井产能半解析模型

目前多级压裂水平井产能计算模型研究较多，但大部分产能模型都没有考虑裂缝导流能力时效性对产能的影响。而室内实验和矿场实践表明，在实际生产过程中，裂缝导流能力随时间不断变化。本文利用源函数法求解油藏渗流模型，利用有限差分方法离散求解考虑裂缝导流能力随时间变化的裂缝渗流模型，并通过裂缝和油藏接触面处的流量和压力相等这一边界条件，将这两者进行了耦合，得到了考虑裂缝长期导流能力的多级压裂水平井产能半解析模型。模型计算结果表明，导流能力随时间的降低，在产能预测分析中是不可忽略的因素，这一因素会改变油藏的渗流场分布，改变裂缝内的流量和压力分布，会使更多的流体通过井筒附近的裂缝流入井内。本文建立的模型和计算结果对于储层产能预测研究和实际生产都有较大的指导意义。

Semi-analytical model of multi-stage fractured horizontal well productivity considering time-dependent fracture conductivity

At present, the models for calculating the productivity of multi-stage fractured horizontal well are researched more, but few productivity formulas consider the effect of the timeliness of fracture conductivity on the productivity. Laboratory experiments and field practice show that the fracture conductivity changes continuously over the time in the process of actual production. In this paper, the reservoir seepage model was solved by means of the source function method, and the reservoir seepage model considering the change of fracture conductivity over the time was solved discretely by means of the finite difference method. Then, both of them were coupled based on the boundary condition that the flow rate and pressure at the contact plane of fracture and oil reservoir are equal. In this way, the semi-analytical model of multi-stage fractured horizontal well productivity considering long-term fracture conductivity was established. The simulation calculation results show that the flow conductivity decreases over the time and it is a nonnegligible factor in the productivity prediction and analysis, for it can change the distribution of seepage field in oil reservoirs and the distribution of flow rate and pressure inside the fractures to make more fluid flow into the well through the fractures near the wellbore. This newly established model and the calculation results in this paper play an important role in guiding reservoir productivity prediction and actual production.