致密油藏水力压裂复杂缝网单井产能预测

致密油藏压裂裂缝的非线性扩展特征具有统计自相似性，可以采用类分形分叉树状网络来表征压裂复杂裂缝网络系统。基于流体扩散理论和压降叠加原理，采用半解析方法建立了相应的油藏渗流和裂缝渗流数学模型，通过迭代求解，对压裂井的不稳定产能进行预测，并分析了产能影响因素：基质渗透率越小，分支缝产量贡献比越大；生产初期，分支缝产量贡献较小，拟稳态阶段，分支缝产量占总产量比例迅速增加，稳产时间延长；裂缝系统越复杂，有效裂缝接触面积越大，产量越高；分支缝导流能力越大，产量越高；复杂缝网和分支缝导流能力的提高，有利于致密油藏压裂井的高产、稳产。

Productivity Prediction of Fracturing Well with Complex Hydraulic Fracture Network in Tight Oil Reservoir

The nonlinear fracture extension in tight oil reservoir by hydraulic fracturing is characterized by statistic self-similarity, and the complex hydraulic fracture system can be described by the fractal bifurcate tree network theory. Based on fluid diffusion theory and pressure drop superposition principle, this paper uses semi?analytical method to estiblish the corresponding mathematic models for reservoir seepage and fracture seepage, and predicts the unstable productivity of a fracturing well through iterative algorithm, including influencing factors analysis of the productivity. The results show that the smaller the matrix permeability, the greater the contribution ratio of production rate from branch fractures, and the more favorable for generating complex fracture network. During the early production, the production rate from branch fractures is lower; up to quasi?steady state period, the production rate from branch fractures is increased rapidly, and the stable production stage is prolonged. The more complex the hydraulic fracture system, the larger the effective contact area of hydraulic fractures and the higher the production rate; also, the higher the branch fractures flow conductivity, the higher the production rate is. So, additional complex hydraulic fracture networks and incremental branch fractures flow conductivity are favorable for high and stable production of a fracturing well in tight oil reservoir