多段压裂水平井三线性流模型适用性研究

Study on applicability of trilinear flow model for multistage fractured horizontal well

三线性流模型是目前求解多段压裂水平井试井模型的常用方法之一。采用正交试验、极差分析法和方差分析法,分析了裂缝半长、内区宽度、储层半长、无因次裂缝导流能力、内区渗透率对三线性流模型与数值模型压力及压力导数双对数曲线拟合的影响。研究表明,影响两种模型压力及压力导数双对数曲线拟合程度的排序为:无因次裂缝导流能力(F_(CD))>内区渗透率(k_I)>裂缝半长(x_f)>储层半长(x_e)>内区宽度(y_e)。无因次裂缝导流能力对两种模型压力特征曲线的拟合有显著影响,当无因次裂缝导流能力小于1时,曲线拟合效果差,线性流模型不适用;当无因次裂缝导流能力大于1时,曲线拟合效果较好,线性流模型适用。

A trilinear flow model is one of the common methods solving the well test models for the multistage fractured horizontal wells.By the orthogonal test,the range analysis method and the variance analysis method,we analyzed the influence of the half frac-ture length,the half reservoir thickness,the width of the inner zone,the dimensionless fracture conductivity and the permeability in inner zone on the double log curves fitting of the pressure and the pressure derivative of the trilinear flow model and numerical mod-el.According to this analysis,the factors affecting the curves of the pressure characteristic curves of two models ranged from more to less are the dimensionless fracture conductivity(FCD),the permeability in inner zone(kI),the half fracture length(xf),the half reservoir thickness(xe)and the width of inner zone(ye).The fracture conductivity affect obviously on the fitting of the pressure char-acteristic curves of two models.When the fracture conductivity is less than 1,the curve fitting effect is poor,so the linear flow mod-el is not applicable.Otherwise,when the fracture conductivity is greater than 1,the curve fitting effect is good,so the linear flow model is suitable.